300 cards from all 30 topics. Pick a group, answer each claim and see how much you really know. Every answer links back to the topic page with the full research.
Read each claim and pick an answer: the card flips to show the verdict and why. Not sure? Use “Just reveal”.
Low fitness is linked to as much extra risk of death as smoking.
Low fitness is linked to as much extra risk of death as smoking.
In Mandsager 2018 (122,007 treadmill tests) being in the lowest fitness group carried a risk comparable to smoking, diabetes or heart disease.
After age 60 your VO2 max can't go up any more.
After age 60 your VO2 max can't go up any more.
Trials in people in their 60s, 70s and even 80s show VO2 max rises with training. Older adults gain a smaller absolute amount, but it matters more for staying independent.
Every 1-MET (3.5 mL/kg/min) gain in fitness is linked to roughly 13% lower risk of death.
Every 1-MET (3.5 mL/kg/min) gain in fitness is linked to roughly 13% lower risk of death.
That is the pooled result of Kodama 2009, a meta-analysis of 33 studies and about 103,000 people.
Losing weight raises your VO2 max.
Losing weight raises your VO2 max.
The number is measured per kilogram, so losing fat lifts it on paper. Your heart and lungs only actually get stronger with training.
Your smartwatch gives you an exact VO2 max.
Your smartwatch gives you an exact VO2 max.
Watches estimate it from heart rate and pace and can be several points off. Treat it as a trend line, not a lab result.
Short hard intervals like 4×4 minutes raise VO2 max more than the same work done at an easy steady pace.
Short hard intervals like 4×4 minutes raise VO2 max more than the same work done at an easy steady pace.
Helgerud 2007 found about a 7% rise after 8 weeks of 4×4 intervals; moderate steady running at matched work barely moved it.
In most healthy people, the heart's pumping power is the main limit on VO2 max.
In most healthy people, the heart's pumping power is the main limit on VO2 max.
Lungs, blood and muscle all play a part, but the amount of blood the heart can push out per beat usually sets the ceiling.
VO2 max is mostly genetic.
VO2 max is mostly genetic.
Family studies (HERITAGE) suggest about half the variation comes from genes. But almost everyone improves when they train.
Only elite athletes get a big health benefit from fitness.
Only elite athletes get a big health benefit from fitness.
The biggest drop in risk comes from moving out of the least-fit group into below average or average.
Without training, VO2 max falls by about 10% each decade after 30.
Without training, VO2 max falls by about 10% each decade after 30.
The decline speeds up after 70. Training slows it and can set you back years on the curve.
A resting heart rate that creeps up over several days can be an early sign of illness or overtraining.
A resting heart rate that creeps up over several days can be an early sign of illness or overtraining.
Wearable studies show RHR often rises a few beats before symptoms of infection appear, and after poor sleep, alcohol or hard training.
A resting heart rate of 50 always means something is wrong.
A resting heart rate of 50 always means something is wrong.
Fit people often sit in the 40s or 50s because each beat moves more blood. It's only a concern if you also feel dizzy, faint or breathless.
Measuring right after waking, before getting up, gives the most consistent reading.
Measuring right after waking, before getting up, gives the most consistent reading.
Caffeine, standing, food and stress all push heart rate up. The same quiet moment each day makes trends easy to see.
Normal resting heart rate is 60 to 100 beats a minute.
Normal resting heart rate is 60 to 100 beats a minute.
That is the textbook range, but large studies find risk starts rising above about 70–80, even inside the 'normal' band.
Regular aerobic exercise usually lowers resting heart rate.
Regular aerobic exercise usually lowers resting heart rate.
Training enlarges the heart's stroke volume, so it needs fewer beats to move the same blood. Drops of 5–10 bpm are common.
Your resting heart rate is fixed by your genes.
Your resting heart rate is fixed by your genes.
Genes set a starting point, but fitness, sleep, alcohol, stress, illness and medicines all move it within weeks.
One evening of drinking can raise your overnight heart rate.
One evening of drinking can raise your overnight heart rate.
Alcohol speeds the heart and lowers HRV during sleep; many wearable users see it plainly the next morning.
A lower resting heart rate is always better.
A lower resting heart rate is always better.
Lower is usually a sign of fitness, but a very slow rate with symptoms, or caused by medicine or heart block, needs checking.
Dehydration and heat can raise your resting heart rate.
Dehydration and heat can raise your resting heart rate.
With less fluid in the blood vessels, the heart beats faster to keep blood pressure up.
You need a gadget to measure resting heart rate.
You need a gadget to measure resting heart rate.
Two fingers on your wrist or neck, count for 30 seconds and double it. Repeat on a few mornings and take the average.
Higher heart rate variability usually means your 'rest and digest' nervous system is more active.
Higher heart rate variability usually means your 'rest and digest' nervous system is more active.
HRV reflects the vagus nerve gently slowing and speeding the heart with each breath. More variation tends to mean better recovery.
You should compare your HRV with your friends' numbers.
You should compare your HRV with your friends' numbers.
HRV varies hugely between people and with age, sex and device. Compare yourself only with your own normal range.
Slow breathing at about six breaths a minute can raise HRV in the moment.
Slow breathing at about six breaths a minute can raise HRV in the moment.
Slow breathing lines up heart rhythm with breathing (resonance), which increases beat-to-beat variation.
A low HRV reading means you should skip training today.
A low HRV reading means you should skip training today.
One low morning is a hint, not a rule. Several days below your normal range, plus feeling rough, is a better reason to go easy.
HRV naturally falls with age.
HRV naturally falls with age.
On average it drops steadily from your twenties onwards, so age-based comparison matters if you look at any norms.
A higher HRV is always healthier.
A higher HRV is always healthier.
Some heart rhythm problems, such as frequent extra beats or atrial fibrillation, can make HRV look falsely high.
Alcohol in the evening reliably lowers overnight HRV.
Alcohol in the evening reliably lowers overnight HRV.
Studies and large wearable datasets show a dose-dependent drop that can last into the next night.
Smartwatches measure HRV accurately.
Smartwatches measure HRV accurately.
Chest straps and overnight readings are fairly good. Wrist readings taken during the day while moving are much less reliable.
Regular aerobic exercise tends to raise resting HRV over time.
Regular aerobic exercise tends to raise resting HRV over time.
Trials show modest increases after weeks of endurance training, along with a lower resting heart rate.
HRV is the same thing as heart rate.
HRV is the same thing as heart rate.
Heart rate counts beats per minute. HRV measures how much the gap between beats changes, in milliseconds.
You need 10,000 steps a day for any health benefit.
You need 10,000 steps a day for any health benefit.
The 10,000 figure came from a 1960s Japanese pedometer ad. Death risk drops steeply from about 2,500 up to around 7,000–9,000 steps.
Even about 4,000 steps a day is linked to lower risk of death than 2,000.
Even about 4,000 steps a day is linked to lower risk of death than 2,000.
Large meta-analyses (Paluch 2022, Banach 2023) find benefits start well below 10,000 steps.
Guidelines recommend 150–300 minutes of moderate or 75–150 minutes of vigorous activity a week.
Guidelines recommend 150–300 minutes of moderate or 75–150 minutes of vigorous activity a week.
This is the WHO and US guideline. More than the upper end still brings some extra benefit.
Brisk walking counts as exercise.
Brisk walking counts as exercise.
Yes, if it's brisk enough to make talking a little harder. A slow stroll still helps but counts less.
Weekend warriors who fit all their activity into one or two days get similar benefits to daily exercisers.
Weekend warriors who fit all their activity into one or two days get similar benefits to daily exercisers.
In UK Biobank and US survey data, total weekly activity mattered more than how it was spread out.
Exercise doesn't count unless you do at least 10 minutes in a row.
Exercise doesn't count unless you do at least 10 minutes in a row.
Newer guidelines dropped the 10-minute rule. Short bouts, like brisk stairs, add up.
Short bursts of vigorous everyday activity, like climbing stairs fast, are linked to lower death risk.
Short bursts of vigorous everyday activity, like climbing stairs fast, are linked to lower death risk.
Wrist-worn accelerometer data (Stamatakis 2022) found 3–4 one-minute bursts a day linked with about 40% lower risk.
Faster walking pace matters more than step count.
Faster walking pace matters more than step count.
Both matter. Pace (cadence) adds benefit on top of steps, but total steps still carry most of the effect.
Sitting for long hours is linked to higher risk even if you exercise.
Sitting for long hours is linked to higher risk even if you exercise.
About 30–40 minutes of moderate activity a day appears to cancel out most of the extra risk from long sitting.
Cardio burns away muscle.
Cardio burns away muscle.
Moderate cardio doesn't cost muscle if you also do strength work and eat enough protein.
High blood pressure usually causes no symptoms at all.
High blood pressure usually causes no symptoms at all.
That's why it's called a silent killer. The only way to know is to measure it.
Headaches and nosebleeds are reliable signs of high blood pressure.
Headaches and nosebleeds are reliable signs of high blood pressure.
Most people with high blood pressure have neither. Only very high readings in a crisis tend to cause headaches.
Cutting salt lowers blood pressure in most people, especially those whose pressure is already high.
Cutting salt lowers blood pressure in most people, especially those whose pressure is already high.
Trials like DASH-Sodium show clear drops; swapping to a potassium salt substitute also cut strokes in the SSaSS trial.
Home readings are often more useful than one reading at the clinic.
Home readings are often more useful than one reading at the clinic.
'White coat' pressure can be high at the doctor. An average of home readings over a week is closer to your real level.
A reading of 130/85 is fine.
A reading of 130/85 is fine.
It used to be called normal. Current US guidelines call 130–139 systolic stage 1 high; European ones call it high-normal. Either way it's worth acting on.
Once your blood pressure is normal on pills, you can stop them.
Once your blood pressure is normal on pills, you can stop them.
The pills are usually what's keeping it normal. Stop only with your doctor, and usually after lifestyle changes have done real work.
Isometric exercise like wall sits and plank holds lowers blood pressure well.
Isometric exercise like wall sits and plank holds lowers blood pressure well.
A 2023 meta-analysis (Edwards, BJSM) ranked isometric training as the most effective exercise type for lowering resting pressure.
Sitting with your arm unsupported or legs crossed can push the reading up.
Sitting with your arm unsupported or legs crossed can push the reading up.
Sit back, feet flat, arm resting at heart level, and rest 5 minutes before measuring.
Coffee raises blood pressure.
Coffee raises blood pressure.
It causes a short rise for a few hours, especially in people who don't drink it often. Regular moderate coffee isn't linked to long-term high pressure.
Blood pressure naturally goes up with age, so it's nothing to worry about.
Blood pressure naturally goes up with age, so it's nothing to worry about.
It's common, but not harmless. Every 20 mmHg higher systolic pressure roughly doubles heart disease and stroke risk.
Grip strength predicts risk of death better than blood pressure in some large studies.
Grip strength predicts risk of death better than blood pressure in some large studies.
In the PURE study (Leong 2015, nearly 140,000 people) each 5 kg lower grip was linked to 16% higher death risk.
Lifting weights makes women bulky.
Lifting weights makes women bulky.
Women have far less testosterone; building big muscle takes years of focused effort. Most women get stronger and leaner.
Adults lose roughly 3–8% of muscle per decade after 30 without strength training.
Adults lose roughly 3–8% of muscle per decade after 30 without strength training.
The loss speeds up after 60 (sarcopenia) and is a major driver of falls and frailty.
You can build muscle in your 80s and 90s.
You can build muscle in your 80s and 90s.
Fiatarone 1990: nursing-home residents aged 86–96 nearly doubled their strength after 8 weeks of training.
You need heavy weights to build muscle.
You need heavy weights to build muscle.
Light weights work too if you take sets close to failure. Heavy loads build maximal strength better.
Just 30–60 minutes of strength training a week is linked to lower death risk.
Just 30–60 minutes of strength training a week is linked to lower death risk.
Momma 2022 meta-analysis: the benefit peaked around 30–60 minutes a week.
Muscle turns into fat when you stop training.
Muscle turns into fat when you stop training.
They're different tissues. Muscle shrinks and fat may grow, but one never turns into the other.
Soreness the next day means it was a good workout.
Soreness the next day means it was a good workout.
Soreness mostly reflects new or unfamiliar exercise, not how much muscle you'll build.
Strength training improves blood sugar control.
Strength training improves blood sugar control.
Muscle is the biggest place your body stores glucose. More muscle and regular training improve insulin sensitivity.
Strength training is bad for your joints.
Strength training is bad for your joints.
Done with good form and gradual progress, it usually reduces joint pain, including in knee osteoarthritis.
Not being able to stand on one leg for 10 seconds in midlife is linked to higher death risk.
Not being able to stand on one leg for 10 seconds in midlife is linked to higher death risk.
Araujo 2022 (BJSM) found people aged 51–75 who failed the test had about 84% higher risk of death over 7 years.
Tai chi reduces falls in older adults.
Tai chi reduces falls in older adults.
Several trials and meta-analyses show tai chi cuts falls by roughly 20–40%.
Balance gets worse with age and nothing can be done.
Balance gets worse with age and nothing can be done.
Balance training works at any age. Falls drop by about a quarter in exercise trials (Sherrington, Cochrane 2019).
The sit-to-rise test (getting down to the floor and up without using hands) predicts survival.
The sit-to-rise test (getting down to the floor and up without using hands) predicts survival.
Brito 2014: each point on the 10-point test was linked to about 21% lower risk of death.
Stretching every day prevents injury.
Stretching every day prevents injury.
Static stretching before exercise does little to prevent injury. A dynamic warm-up and strength work do more.
Strong legs and hips are key to good balance.
Strong legs and hips are key to good balance.
Balance depends on the strength to correct a wobble, not only on the inner ear and nerves.
Closing your eyes makes no difference to balance.
Closing your eyes makes no difference to balance.
Vision does a lot of the work. Eyes-closed balance drops much faster with age, which is why it's a useful test.
Falls are the leading cause of injury death in adults over 65.
Falls are the leading cause of injury death in adults over 65.
In many countries falls top the list, which is why balance training counts as a longevity habit.
Flexibility is only for yoga fans.
Flexibility is only for yoga fans.
You don't need splits, but enough range in hips, ankles and shoulders keeps everyday movements and balance easy.
Practising balance on one leg while brushing your teeth is a real training method.
Practising balance on one leg while brushing your teeth is a real training method.
Small daily doses add up; progression (eyes closed, soft surface) keeps it challenging.
Waist size predicts health risk better than weight or BMI alone.
Waist size predicts health risk better than weight or BMI alone.
Fat around the organs (visceral fat) drives most of the risk, and waist size tracks it better than total weight.
Keeping your waist under half your height is a simple, useful target.
Keeping your waist under half your height is a simple, useful target.
A waist-to-height ratio under 0.5 is recommended by the UK's NICE for adults of all ethnicities.
Sit-ups burn belly fat.
Sit-ups burn belly fat.
You can't spot-reduce fat. Belly fat goes down with overall fat loss from food, activity and sleep.
BMI is useless.
BMI is useless.
It's a rough population tool that misses muscle and fat distribution, but very high BMI is still clearly linked to harm.
Visceral fat responds well to exercise, even without much weight loss.
Visceral fat responds well to exercise, even without much weight loss.
Trials show aerobic exercise cuts visceral fat noticeably, sometimes with little change on the scales.
Thin people can't have unhealthy fat levels.
Thin people can't have unhealthy fat levels.
'Normal weight obesity' and fat around the liver happen in slim people too, especially with little muscle.
Poor sleep is linked to gaining more belly fat.
Poor sleep is linked to gaining more belly fat.
Short sleep raises hunger hormones and cravings, and studies link it to more visceral fat over time.
Body fat scales tell you your exact body fat.
Body fat scales tell you your exact body fat.
Home bioimpedance scales can be off by several percent and swing with hydration. Use them for trends at best.
Men tend to store more fat around the organs than women before menopause.
Men tend to store more fat around the organs than women before menopause.
After menopause women's fat shifts more towards the belly too.
Measuring your waist means measuring at your trouser line.
Measuring your waist means measuring at your trouser line.
Measure at the midpoint between your lowest rib and the top of your hip bone, after breathing out.
Most adults need 7–9 hours of sleep a night.
Most adults need 7–9 hours of sleep a night.
That's the consensus of the American Academy of Sleep Medicine and Sleep Research Society. Very few people truly thrive on under 6.
You can fully catch up on lost sleep at the weekend.
You can fully catch up on lost sleep at the weekend.
Lie-ins help a little, but studies show weekday sleep loss still harms blood sugar control and alertness.
Keeping a regular wake-up time matters as much as total hours.
Keeping a regular wake-up time matters as much as total hours.
UK Biobank studies (2023–24) found sleep regularity predicted death risk even more strongly than sleep duration.
Alcohol helps you sleep.
Alcohol helps you sleep.
It helps you fall asleep faster, but breaks up the second half of the night and cuts REM sleep.
During deep sleep the brain clears waste products faster.
During deep sleep the brain clears waste products faster.
Animal studies of the glymphatic system show waste clearance rises in sleep; human work points the same way.
Older people need less sleep.
Older people need less sleep.
Older adults often sleep less well, but their need stays at about 7–8 hours.
Loud snoring with gasping or pauses can be a sign of sleep apnoea.
Loud snoring with gasping or pauses can be a sign of sleep apnoea.
It's very common, often undiagnosed and linked to high blood pressure, heart disease and daytime sleepiness. It's treatable.
CBT for insomnia works better long-term than sleeping pills.
CBT for insomnia works better long-term than sleeping pills.
Guidelines recommend CBT-I as first treatment; its benefits last after treatment ends.
Screens before bed ruin sleep because of blue light.
Screens before bed ruin sleep because of blue light.
Light matters a bit, but what you're doing (scrolling, stress, staying up later) seems to matter more.
If you can't sleep, staying in bed and trying harder is best.
If you can't sleep, staying in bed and trying harder is best.
If you're awake more than about 20 minutes, get up, do something calm in dim light and return when sleepy.
Autophagy is the cell's recycling system for broken proteins and parts.
Autophagy is the cell's recycling system for broken proteins and parts.
Its discovery in yeast won Yoshinori Ohsumi the 2016 Nobel Prize.
Autophagy switches on exactly after 16 hours of fasting.
Autophagy switches on exactly after 16 hours of fasting.
There's no known switch time in humans. Most timing data come from mice, which have much faster metabolisms.
Intermittent fasting is better for weight loss than normal calorie cutting.
Intermittent fasting is better for weight loss than normal calorie cutting.
Trials find similar weight loss when total calories match. It suits some people because it's easier to stick to.
We can't yet measure autophagy in a living person's organs with a simple test.
We can't yet measure autophagy in a living person's organs with a simple test.
Human studies rely on indirect markers in blood cells or muscle biopsies, which is why claims should be cautious.
A coffee or black tea ruins your fast.
A coffee or black tea ruins your fast.
Plain black coffee or tea has almost no calories. Whether it affects autophagy in humans is unknown.
Exercise can also trigger autophagy in muscle.
Exercise can also trigger autophagy in muscle.
Human muscle biopsy studies show autophagy markers rise after exercise.
Time-restricted eating helps blood sugar.
Time-restricted eating helps blood sugar.
Some trials show better insulin sensitivity, especially with an early eating window; others find little effect beyond weight loss.
Longer fasts are always better.
Longer fasts are always better.
Multi-day fasts carry risks like muscle loss, low blood pressure and refeeding problems, and aren't proven to extend human life.
People with diabetes on insulin or certain pills shouldn't fast without medical advice.
People with diabetes on insulin or certain pills shouldn't fast without medical advice.
Fasting can cause dangerous low blood sugar when combined with these medicines.
Fasting extends lifespan.
Fasting extends lifespan.
It does in many animals. In humans there's no direct lifespan evidence yet, only changes in risk markers.
Regular sauna use is linked to lower heart disease risk in Finnish men.
Regular sauna use is linked to lower heart disease risk in Finnish men.
Laukkanen 2015 (2,315 men): 4–7 sessions a week was linked to about 50% lower risk of fatal heart disease than 1 a week.
Sauna directly causes longer life.
Sauna directly causes longer life.
The big studies are observational in Finland, where sauna is part of daily life. Trials show better blood pressure and vessel function, but not lifespan yet.
You sweat out toxins in a sauna.
You sweat out toxins in a sauna.
Sweat is mostly water and salt. The liver and kidneys do the detox work.
A sauna session raises heart rate as much as moderate exercise.
A sauna session raises heart rate as much as moderate exercise.
Heart rate often reaches 100–150 bpm, which is part of why it's been called 'passive cardio'.
Drinking alcohol in the sauna is dangerous.
Drinking alcohol in the sauna is dangerous.
It raises the risk of low blood pressure, heart rhythm problems and fainting; many sauna deaths involve alcohol.
Hot baths have similar benefits to sauna.
Hot baths have similar benefits to sauna.
Japanese studies link frequent hot baths to lower heart risk too, but the evidence is thinner.
Cold plunges after sauna are proven to add years to your life.
Cold plunges after sauna are proven to add years to your life.
Cold exposure can boost mood and alertness, but there's no good evidence it extends life.
Heat exposure triggers heat shock proteins that help repair damaged proteins.
Heat exposure triggers heat shock proteins that help repair damaged proteins.
This is well shown in cells and animals and is one proposed reason for sauna's benefits.
Sauna lowers blood pressure in the short term.
Sauna lowers blood pressure in the short term.
Trials show readings drop after a session, and regular use is linked to lower long-term risk of hypertension.
Sauna is unsafe for everyone with heart disease.
Sauna is unsafe for everyone with heart disease.
For people with stable heart disease it's usually safe in moderation, but unstable angina, recent heart attack or severe aortic stenosis are exceptions. Ask your doctor.
Muscles grow and adapt during rest, not during the workout itself.
Muscles grow and adapt during rest, not during the workout itself.
Training is the signal; repair and growth happen over the following 24–72 hours.
Ice baths right after strength training help you build more muscle.
Ice baths right after strength training help you build more muscle.
Roberts 2015 found regular cold water immersion after lifting blunted muscle and strength gains.
Sleep is the most powerful recovery tool.
Sleep is the most powerful recovery tool.
Sleep loss lowers strength, reaction time and muscle repair, and raises injury risk in athletes.
Stretching after exercise prevents soreness.
Stretching after exercise prevents soreness.
Reviews show stretching barely reduces soreness. It can still help flexibility over time.
A deload week every few weeks can help you keep improving.
A deload week every few weeks can help you keep improving.
Planned lighter weeks reduce fatigue and are common in structured training.
If you're not sore, you didn't work hard enough.
If you're not sore, you didn't work hard enough.
Soreness drops as your body gets used to a routine, but progress continues.
Light movement on rest days can speed recovery.
Light movement on rest days can speed recovery.
Easy walking or cycling increases blood flow without adding much stress.
Massage guns and foam rollers speed muscle recovery.
Massage guns and foam rollers speed muscle recovery.
They can reduce soreness and feel good, but effects on performance are small.
Rising resting heart rate and falling HRV over several days can signal you need more recovery.
Rising resting heart rate and falling HRV over several days can signal you need more recovery.
Many athletes use these trends, along with mood and sleep, to adjust training.
Overtraining only happens to elite athletes.
Overtraining only happens to elite athletes.
Anyone can overreach if training rises faster than sleep, food and rest allow, especially alongside work stress.
A walk of 10–15 minutes after a meal lowers the blood sugar spike.
A walk of 10–15 minutes after a meal lowers the blood sugar spike.
Studies show light walking after eating blunts the rise, because working muscles pull glucose out of the blood.
Only people with diabetes need to care about blood sugar.
Only people with diabetes need to care about blood sugar.
Prediabetes is very common and usually silent. Insulin resistance builds for years before a diagnosis.
Eating vegetables and protein before carbs can lower the glucose spike from a meal.
Eating vegetables and protein before carbs can lower the glucose spike from a meal.
Small trials show food order reduces the peak, especially in people with type 2 diabetes.
Fruit is bad because it contains sugar.
Fruit is bad because it contains sugar.
Whole fruit comes with fibre and is linked to lower diabetes risk. Fruit juice is a different story.
HbA1c shows your average blood sugar over about three months.
HbA1c shows your average blood sugar over about three months.
It measures how much sugar has stuck to red blood cells, which live around 120 days.
A single glucose spike on a monitor means a food is unhealthy for you.
A single glucose spike on a monitor means a food is unhealthy for you.
Spikes after meals are normal. What matters most is your overall average and how quickly levels come back down.
Type 2 diabetes can go into remission with large weight loss.
Type 2 diabetes can go into remission with large weight loss.
In the DiRECT trial, almost half of people who followed a diet programme were in remission after one year.
Artificial sweeteners help with blood sugar.
Artificial sweeteners help with blood sugar.
They don't raise glucose directly, but long-term benefits are unclear and the WHO advises against relying on them for weight control.
Poor sleep makes blood sugar control worse the next day.
Poor sleep makes blood sugar control worse the next day.
Even one night of short sleep reduces insulin sensitivity in healthy adults.
Brown sugar and honey are much healthier than white sugar.
Brown sugar and honey are much healthier than white sugar.
They're almost the same to your body: mostly glucose and fructose, with tiny amounts of minerals.
Most adults eat far less fibre than recommended.
Most adults eat far less fibre than recommended.
Guidelines suggest 25–30 g a day or more; many people eat around 15–20 g.
Eating 25–29 g of fibre a day is linked to 15–30% lower risk of death and heart disease.
Eating 25–29 g of fibre a day is linked to 15–30% lower risk of death and heart disease.
Reynolds 2019 (Lancet) pooled 185 studies and 58 trials; more fibre was even better.
Carbs are the main cause of weight gain.
Carbs are the main cause of weight gain.
Diets low in carbs or low in fat lead to similar weight loss when calories match (DIETFITS trial).
All ultra-processed foods are equally bad.
All ultra-processed foods are equally bad.
Sugary drinks and processed meats show the clearest harm. Some, like wholegrain bread or plain yoghurt, look neutral or even helpful.
Mediterranean-style eating cut heart attacks and strokes in a large trial.
Mediterranean-style eating cut heart attacks and strokes in a large trial.
PREDIMED found about 30% fewer major cardiovascular events with extra olive oil or nuts.
Frozen vegetables are less nutritious than fresh.
Frozen vegetables are less nutritious than fresh.
They're frozen soon after picking, so they often hold vitamins as well as or better than fresh ones stored for days.
Beans and lentils are among the best sources of fibre.
Beans and lentils are among the best sources of fibre.
One cup of cooked lentils has around 15 g of fibre, plus protein.
Eggs are bad for your cholesterol.
Eggs are bad for your cholesterol.
For most people, eating an egg a day has little effect on heart risk. People with diabetes or high LDL may want to be more careful.
Processed meat is classed as a cause of bowel cancer.
Processed meat is classed as a cause of bowel cancer.
The WHO's cancer agency (IARC) classified it as Group 1 in 2015; each 50 g a day raises risk by about 18%.
Eating late at night automatically makes you gain weight.
Eating late at night automatically makes you gain weight.
Total intake over the day matters more, though late eating can hurt sleep and blood sugar for some people.
Strong social relationships are linked to about 50% better odds of survival.
Strong social relationships are linked to about 50% better odds of survival.
Holt-Lunstad 2010 pooled 148 studies and over 300,000 people.
Loneliness is linked to higher risk of heart disease and stroke.
Loneliness is linked to higher risk of heart disease and stroke.
Valtorta 2016 found about 29% higher heart disease risk and 32% higher stroke risk.
Loneliness only affects older people.
Loneliness only affects older people.
Surveys find young adults report some of the highest rates of loneliness.
Being alone is the same as being lonely.
Being alone is the same as being lonely.
Social isolation (few contacts) and loneliness (feeling disconnected) overlap, but you can feel lonely in a crowd or content alone.
Volunteering is linked to better health and longer life.
Volunteering is linked to better health and longer life.
Studies of older volunteers link it to lower death risk and better mood, partly through purpose and connection.
Online contact is worthless for wellbeing.
Online contact is worthless for wellbeing.
Video and voice calls can help, especially when they support in-person ties. Passive scrolling tends not to.
The Harvard Study of Adult Development found relationship quality at 50 predicted health at 80.
The Harvard Study of Adult Development found relationship quality at 50 predicted health at 80.
Satisfaction with relationships was a better predictor than cholesterol levels.
You need lots of friends to be healthy.
You need lots of friends to be healthy.
Quality matters more than quantity. A few close, reliable relationships carry most of the benefit.
Chronic loneliness is linked to higher dementia risk.
Chronic loneliness is linked to higher dementia risk.
Meta-analyses find around 30% higher risk, though some of the link may be early dementia causing withdrawal.
The US Surgeon General declared loneliness a public health epidemic in 2023.
The US Surgeon General declared loneliness a public health epidemic in 2023.
The advisory compared its risk to smoking up to 15 cigarettes a day.
Active adults and older people benefit from about 1.2–1.6 g of protein per kg of body weight a day.
Active adults and older people benefit from about 1.2–1.6 g of protein per kg of body weight a day.
The basic 0.8 g/kg recommendation prevents deficiency; strength gains in trials plateau around 1.6 g/kg.
Your body can only use 30 g of protein from one meal.
Your body can only use 30 g of protein from one meal.
A 2023 trial (Trommelen) found the body kept building muscle for 12 hours after 100 g. Spreading it out is still sensible.
High-protein diets damage healthy kidneys.
High-protein diets damage healthy kidneys.
In people with healthy kidneys, studies haven't shown harm. People with kidney disease should follow medical advice.
Older adults need more protein per meal to trigger muscle building.
Older adults need more protein per meal to trigger muscle building.
Ageing muscle responds less ('anabolic resistance'), so around 30–40 g in a meal works better than 20 g.
Plant protein is incomplete and can't build muscle.
Plant protein is incomplete and can't build muscle.
Single plants can be low in some amino acids, but mixing sources (beans plus grains) or eating a bit more works well.
Protein keeps you fuller than the same calories of carbs or fat.
Protein keeps you fuller than the same calories of carbs or fat.
It's the most filling macronutrient, which helps with weight control.
You need protein shakes to build muscle.
You need protein shakes to build muscle.
They're convenient, not essential. Food works just as well if you get enough total protein.
Leucine is a key amino acid for turning on muscle building.
Leucine is a key amino acid for turning on muscle building.
Whey, eggs, meat and fish are rich in it; soy is a good plant source.
You must eat protein within 30 minutes after training.
You must eat protein within 30 minutes after training.
The 'anabolic window' is much wider; total daily protein matters far more.
Eating enough protein while losing weight helps protect muscle.
Eating enough protein while losing weight helps protect muscle.
Trials show higher protein plus strength training keeps more lean mass during a calorie deficit.
Creatine is one of the most studied and effective supplements for strength.
Creatine is one of the most studied and effective supplements for strength.
Hundreds of trials show it boosts strength and muscle gains with training, and it's safe for healthy people at 3–5 g a day.
Multivitamins help healthy people live longer.
Multivitamins help healthy people live longer.
Large studies, including a 2024 analysis of almost 400,000 US adults, found no lower risk of death.
Vitamin D supplements help people who are actually low in it.
Vitamin D supplements help people who are actually low in it.
In people with deficiency, supplements improve bone health; in people with normal levels, trials like VITAL found little benefit.
Fish oil prevents heart attacks.
Fish oil prevents heart attacks.
Ordinary doses showed little benefit in big trials. A high-dose prescription form (REDUCE-IT) cut events in high-risk patients.
Supplements aren't tested like medicines before they're sold.
Supplements aren't tested like medicines before they're sold.
In the US and many countries, makers don't need to prove they work or contain what the label says before selling.
Natural supplements can't interact with medicines.
Natural supplements can't interact with medicines.
St John's wort, for example, weakens the pill, blood thinners and many other drugs.
Very high doses of some vitamins can cause harm.
Very high doses of some vitamins can cause harm.
Too much vitamin A, D or B6 over time can damage the liver, kidneys or nerves.
Magnesium improves sleep.
Magnesium improves sleep.
It may help people who are low in magnesium; evidence in people with normal levels is weak.
Folic acid before and in early pregnancy reduces neural tube defects.
Folic acid before and in early pregnancy reduces neural tube defects.
This is one of the strongest supplement findings, which is why it's recommended for anyone who might become pregnant.
If a little is good, more is better.
If a little is good, more is better.
Most vitamins have a sweet spot. Beta-carotene in smokers raised lung cancer risk in trials.
There's no level of drinking that's completely risk-free for cancer.
There's no level of drinking that's completely risk-free for cancer.
The WHO says risk starts at the first drink; alcohol causes at least seven cancers, including breast and bowel.
A glass of red wine a day is good for your heart.
A glass of red wine a day is good for your heart.
Older studies suggested it, but they compared drinkers with ex-drinkers who quit due to illness. Newer, better studies show little or no benefit.
Quitting smoking at any age adds years of life.
Quitting smoking at any age adds years of life.
Stopping by 40 avoids about 90% of the extra risk; even quitting at 60 adds years.
Vaping is completely harmless.
Vaping is completely harmless.
It's far less harmful than smoking and helps people quit, but it isn't harmless, especially for non-smokers and young people.
Alcohol disrupts sleep even when it makes you drowsy.
Alcohol disrupts sleep even when it makes you drowsy.
It cuts REM sleep and causes more waking in the second half of the night.
Heavy drinking raises blood pressure.
Heavy drinking raises blood pressure.
Cutting back lowers it within weeks in people who drink more than two drinks a day.
Light smoking (a few a day) is basically safe.
Light smoking (a few a day) is basically safe.
Even one to four cigarettes a day nearly triples the risk of heart disease death.
Beer is less harmful than spirits.
Beer is less harmful than spirits.
The harm comes from the alcohol itself, whatever the drink. Spirits just pack it into a smaller volume.
Nicotine replacement plus support more than doubles the chance of quitting.
Nicotine replacement plus support more than doubles the chance of quitting.
Combining patches with gum or lozenges and behavioural support works best.
Drinking water or coffee sobers you up faster.
Drinking water or coffee sobers you up faster.
Only time clears alcohol. The liver processes roughly one drink an hour.
Short-term stress can sharpen focus and performance.
Short-term stress can sharpen focus and performance.
Acute stress hormones help in the moment; the problem is stress that never switches off.
Chronic stress is linked to higher blood pressure and heart disease.
Chronic stress is linked to higher blood pressure and heart disease.
The INTERHEART study found psychosocial stress raised heart attack risk about as much as high blood pressure.
Stress is all in your head.
Stress is all in your head.
It changes heart rate, blood pressure, blood sugar, immunity and sleep through hormones and nerves.
A long, slow exhale calms the nervous system.
A long, slow exhale calms the nervous system.
Breathing out activates the vagus nerve; the 'physiological sigh' (two inhales, long exhale) reduced stress in a 2023 trial.
Exercise is a stress reliever.
Exercise is a stress reliever.
Regular exercise lowers stress over time, but very hard training adds stress if you're already exhausted.
Time in nature lowers stress.
Time in nature lowers stress.
About 2 hours a week in green space is linked to better wellbeing (White 2019, 20,000 people).
Venting anger by hitting a pillow helps release stress.
Venting anger by hitting a pillow helps release stress.
A 2024 meta-analysis found venting doesn't reduce anger; calming activities do.
Mindfulness programmes can reduce anxiety and stress.
Mindfulness programmes can reduce anxiety and stress.
Trials show modest benefits; an 8-week course was as effective as an anxiety drug in a 2022 trial (Hoge, JAMA Psychiatry).
Cortisol is the bad stress hormone.
Cortisol is the bad stress hormone.
Cortisol is essential: it wakes you up and controls inflammation. Problems come when it stays high for too long.
Some people just thrive on constant stress.
Some people just thrive on constant stress.
Some cope better, but long-term high stress still affects the body, even if people feel fine.
Exercise can treat depression about as well as therapy or medicine for many people.
Exercise can treat depression about as well as therapy or medicine for many people.
A 2024 BMJ meta-analysis (Noetel) found walking, jogging, yoga and strength training gave meaningful reductions.
Depression is just feeling sad.
Depression is just feeling sad.
It can also show up as low energy, poor sleep, lack of interest, poor focus, irritability and physical aches.
Talking therapy like CBT works for depression and anxiety.
Talking therapy like CBT works for depression and anxiety.
Many trials show CBT is effective and its benefits often last after therapy ends.
Antidepressants are just placebos.
Antidepressants are just placebos.
On average they work modestly better than placebo, with stronger effects in more severe depression.
Diet quality is linked to mood.
Diet quality is linked to mood.
The SMILES trial found a Mediterranean-style diet improved depression symptoms compared with social support alone.
Asking someone if they're thinking about suicide puts the idea in their head.
Asking someone if they're thinking about suicide puts the idea in their head.
Research shows asking directly does not increase risk and can help people open up.
Sleep problems and depression feed each other.
Sleep problems and depression feed each other.
Insomnia raises the risk of developing depression, and treating insomnia can improve mood.
Social media causes depression in teenagers.
Social media causes depression in teenagers.
Heavy use is linked to worse mood, especially in girls, but the effect sizes are debated and depend on how it's used.
Daylight in the morning can lift mood.
Daylight in the morning can lift mood.
Bright light therapy is an effective treatment for seasonal depression and helps some non-seasonal cases too.
Strong people don't get mental health problems.
Strong people don't get mental health problems.
Mental health conditions are common, affecting about one in four or five people in a given year, whatever their character.
About 45% of dementia cases may be preventable or delayed by tackling 14 risk factors.
About 45% of dementia cases may be preventable or delayed by tackling 14 risk factors.
The 2024 Lancet Commission added high LDL cholesterol and untreated vision loss to its list.
Treating hearing loss may lower dementia risk.
Treating hearing loss may lower dementia risk.
Hearing loss is one of the largest risk factors; the ACHIEVE trial suggested hearing aids slowed decline in higher-risk people.
Brain-training apps make you smarter in general.
Brain-training apps make you smarter in general.
You get better at the games, but improvements rarely transfer to everyday memory or intelligence.
Aerobic exercise can increase the size of the hippocampus.
Aerobic exercise can increase the size of the hippocampus.
Erickson 2011: a year of walking grew the memory centre by about 2% in older adults, reversing 1–2 years of loss.
We only use 10% of our brain.
We only use 10% of our brain.
Brain scans show activity across almost all of it, just not all at once.
Memory naturally declines a lot with age.
Memory naturally declines a lot with age.
Some slowing is normal, but large memory losses are not. Many people keep sharp minds into old age.
Controlling blood pressure in midlife protects the brain.
Controlling blood pressure in midlife protects the brain.
SPRINT MIND found tighter blood pressure control lowered the risk of mild cognitive impairment.
Learning new, challenging skills builds 'cognitive reserve'.
Learning new, challenging skills builds 'cognitive reserve'.
More education and mentally demanding activities are linked to resisting dementia symptoms longer.
Crosswords prevent dementia.
Crosswords prevent dementia.
Mentally active people tend to have lower risk, but it's unclear whether puzzles themselves cause the benefit.
You can't grow new brain cells as an adult.
You can't grow new brain cells as an adult.
Evidence suggests new neurons still form in the adult hippocampus, though how much in humans is debated.
Testosterone in men falls by roughly 1% a year from around age 40.
Testosterone in men falls by roughly 1% a year from around age 40.
The fall is gradual; obesity, poor sleep and illness lower it faster than age alone.
One week of sleeping 5 hours a night lowered young men's testosterone by 10–15%.
One week of sleeping 5 hours a night lowered young men's testosterone by 10–15%.
Leproult & Van Cauter 2011 found this in healthy men in their 20s.
Menopause only affects hot flushes.
Menopause only affects hot flushes.
Falling oestrogen also affects sleep, mood, bones, joints, heart risk, skin and the bladder.
Hormone therapy for menopause causes breast cancer.
Hormone therapy for menopause causes breast cancer.
Combined HRT slightly raises breast cancer risk with long use; oestrogen-only HRT barely does. For most women under 60 the benefits outweigh the risks.
Thyroid problems are much more common in women.
Thyroid problems are much more common in women.
Women are about 5–8 times more likely to have thyroid disease, especially an underactive thyroid.
Adrenal fatigue is a recognised medical condition.
Adrenal fatigue is a recognised medical condition.
Endocrine societies say there's no evidence for it. Tiredness has many other, testable causes.
Strength training and losing excess fat can raise low testosterone in men.
Strength training and losing excess fat can raise low testosterone in men.
Fat tissue converts testosterone to oestrogen, so weight loss often lifts levels.
Testosterone boosters from supplement shops work.
Testosterone boosters from supplement shops work.
Most have no good evidence. Zinc or vitamin D only help if you were deficient.
Insulin is a hormone, and insulin resistance is one of the most common hormone problems.
Insulin is a hormone, and insulin resistance is one of the most common hormone problems.
It affects metabolism, fat storage and, in women, is closely tied to PCOS.
Low libido is always caused by low hormones.
Low libido is always caused by low hormones.
Stress, sleep, mood, relationships and medicines are often bigger causes.
Your gut holds trillions of microbes, with roughly as many bacterial cells as human cells in your body.
Your gut holds trillions of microbes, with roughly as many bacterial cells as human cells in your body.
Estimates put the ratio near 1:1, not the older '10 to 1' claim.
Eating 30 different plants a week is linked to a more diverse gut microbiome.
Eating 30 different plants a week is linked to a more diverse gut microbiome.
The American Gut Project found this pattern; plants include vegetables, fruit, grains, nuts, seeds, beans and herbs.
Fermented foods like yoghurt and kefir increased microbiome diversity in a Stanford trial.
Fermented foods like yoghurt and kefir increased microbiome diversity in a Stanford trial.
Wastyk 2021: 10 weeks of more fermented foods raised diversity and lowered inflammation markers.
Everyone should take a probiotic every day.
Everyone should take a probiotic every day.
Benefits are specific to strains and conditions, like some antibiotic-related diarrhoea. Healthy people show little clear benefit.
Antibiotics wipe out your gut bacteria forever.
Antibiotics wipe out your gut bacteria forever.
They can sharply reduce diversity; most microbes return within weeks to months, but some species may not.
Colon cleanses and detox teas improve gut health.
Colon cleanses and detox teas improve gut health.
They have no proven benefit and can cause dehydration and salt imbalances.
Gut bacteria turn fibre into short-chain fatty acids that feed your gut lining.
Gut bacteria turn fibre into short-chain fatty acids that feed your gut lining.
Butyrate, one of these, is the main fuel for colon cells and helps control inflammation.
Home gut microbiome tests tell you what to eat.
Home gut microbiome tests tell you what to eat.
They show which microbes are present, but there's not enough evidence to turn that into reliable advice.
The gut and brain talk to each other through nerves and chemical signals.
The gut and brain talk to each other through nerves and chemical signals.
The vagus nerve and microbial chemicals link the two, though most mood findings come from animals.
Bloating always means a food intolerance.
Bloating always means a food intolerance.
It's often due to fibre changes, eating fast, constipation or stress; true intolerance is less common.
ApoB is a better measure of heart risk particles than LDL cholesterol alone.
ApoB is a better measure of heart risk particles than LDL cholesterol alone.
Each harmful particle carries one ApoB, so it counts the particles directly. Many experts now favour it.
Lipoprotein(a) is mostly genetic and worth testing once in your life.
Lipoprotein(a) is mostly genetic and worth testing once in your life.
About 1 in 5 people have high Lp(a), which raises heart risk; guidelines now suggest testing it at least once.
If your total cholesterol is normal, your heart risk is low.
If your total cholesterol is normal, your heart risk is low.
Total cholesterol mixes good and bad parts; LDL, ApoB, Lp(a), blood pressure and smoking matter more.
Biological age tests tell you how old your body really is.
Biological age tests tell you how old your body really is.
Epigenetic clocks predict risk in groups, but results for one person can vary between labs and tests.
HbA1c of 5.7–6.4% means prediabetes.
HbA1c of 5.7–6.4% means prediabetes.
Above 6.5% on two tests is the threshold for diagnosing diabetes.
hs-CRP is a marker of low-grade inflammation linked to heart risk.
hs-CRP is a marker of low-grade inflammation linked to heart risk.
Results above 2–3 mg/L, without an infection, suggest higher risk.
More blood tests are always better.
More blood tests are always better.
Testing lots of markers without a reason leads to false alarms and unnecessary follow-up.
A 'normal' lab range means your result is ideal.
A 'normal' lab range means your result is ideal.
Ranges describe the middle 95% of a population, which can include common but unhealthy levels.
Fasting for a lipid test is often no longer required.
Fasting for a lipid test is often no longer required.
Many guidelines accept non-fasting tests; only very high triglycerides need a fasting repeat.
Your VO2 max and grip strength are useful longevity biomarkers too.
Your VO2 max and grip strength are useful longevity biomarkers too.
They predict survival as strongly as many blood tests and are cheap to track.
Everyone needs exactly eight glasses of water a day.
Everyone needs exactly eight glasses of water a day.
Needs vary with size, heat and activity; food and other drinks provide a lot of fluid too.
Coffee and tea count towards your daily fluid intake.
Coffee and tea count towards your daily fluid intake.
At normal amounts their mild diuretic effect is small; they still hydrate overall.
Pale straw-coloured urine is a simple sign of good hydration.
Pale straw-coloured urine is a simple sign of good hydration.
Dark yellow suggests you need more; completely clear can mean you're drinking more than needed.
Thirst comes too late to be useful.
Thirst comes too late to be useful.
For most healthy people thirst works well. Older adults, people in heat and hard exercisers may need to drink before thirst.
Drinking too much water can be dangerous.
Drinking too much water can be dangerous.
Very large amounts in a short time dilute blood sodium (hyponatraemia), which has killed marathon runners.
Older people feel less thirsty and are more prone to dehydration.
Older people feel less thirsty and are more prone to dehydration.
The thirst signal weakens with age, so a regular routine of drinking helps.
Sports drinks are needed for any workout.
Sports drinks are needed for any workout.
For under an hour of exercise, water is enough. Electrolyte drinks help in long, hot or very sweaty sessions.
Even mild dehydration (1–2% of body weight) can affect focus and mood.
Even mild dehydration (1–2% of body weight) can affect focus and mood.
Studies show worse attention and more fatigue at this level, especially in heat.
Drinking more water helps you lose weight.
Drinking more water helps you lose weight.
Water before meals helped a little in some trials, mostly by replacing sugary drinks and adding fullness.
Alkaline water is healthier than ordinary water.
Alkaline water is healthier than ordinary water.
Your stomach acid and kidneys control pH; there's no good evidence it improves health.
Daily sunscreen slows visible skin ageing.
Daily sunscreen slows visible skin ageing.
Hughes 2013: adults who used sunscreen daily showed no detectable increase in skin ageing over 4.5 years.
UV light causes most visible skin ageing on exposed skin.
UV light causes most visible skin ageing on exposed skin.
Wrinkles, spots and sagging on the face and hands are mostly 'photo-ageing'.
You don't need sunscreen on cloudy days.
You don't need sunscreen on cloudy days.
Up to about 80% of UV passes through light cloud.
Retinoids are the best-proven topical treatment for wrinkles.
Retinoids are the best-proven topical treatment for wrinkles.
Tretinoin has decades of trials showing it boosts collagen and smooths fine lines.
Drinking more water gives you better skin.
Drinking more water gives you better skin.
It helps if you're dehydrated, but extra water won't clear wrinkles or acne in well-hydrated people.
Darker skin doesn't need sun protection.
Darker skin doesn't need sun protection.
Darker skin burns less, but can still be damaged, and skin cancer is often caught later.
Smoking speeds up skin ageing.
Smoking speeds up skin ageing.
It reduces blood flow and damages collagen; twin studies show smokers look older than non-smoking twins.
Collagen supplements improve skin.
Collagen supplements improve skin.
Some small, often industry-funded trials show better elasticity; independent evidence is still limited.
Checking moles with the ABCDE rule helps spot melanoma early.
Checking moles with the ABCDE rule helps spot melanoma early.
Look for asymmetry, irregular border, uneven colour, diameter over 6 mm and evolving changes.
A base tan protects you from sunburn.
A base tan protects you from sunburn.
A tan gives roughly SPF 3–4, and tanning itself is a sign of DNA damage.
Spending time outdoors lowers children's risk of becoming short-sighted.
Spending time outdoors lowers children's risk of becoming short-sighted.
Trials in Asia found extra outdoor time at school reduced new myopia; daylight seems to be the key.
Reading in dim light ruins your eyesight.
Reading in dim light ruins your eyesight.
It can tire your eyes, but it doesn't cause lasting damage.
The 20-20-20 rule can ease screen eye strain.
The 20-20-20 rule can ease screen eye strain.
Every 20 minutes, look at something about 20 feet (6 m) away for 20 seconds.
Glaucoma often has no symptoms until vision is lost.
Glaucoma often has no symptoms until vision is lost.
Regular eye tests, especially after 40 or with a family history, catch it early.
Carrots improve your eyesight.
Carrots improve your eyesight.
Vitamin A is needed for vision and prevents night blindness if you're deficient, but extra won't sharpen normal eyes.
Diabetes is a leading cause of preventable blindness.
Diabetes is a leading cause of preventable blindness.
Yearly eye screening and good blood sugar control greatly reduce the risk.
Wearing glasses makes your eyes weaker.
Wearing glasses makes your eyes weaker.
Glasses correct vision; they don't change how your eye develops in adults.
Smoking raises the risk of macular degeneration and cataracts.
Smoking raises the risk of macular degeneration and cataracts.
Smokers have about two to four times the risk of age-related macular degeneration.
Blue-light glasses protect your eyes from screens.
Blue-light glasses protect your eyes from screens.
A 2023 Cochrane review found little evidence they reduce eye strain or protect the retina.
Untreated vision loss is now counted as a dementia risk factor.
Untreated vision loss is now counted as a dementia risk factor.
The 2024 Lancet Commission added it to its list of 14 modifiable risks.
There's one perfect posture you should hold all day.
There's one perfect posture you should hold all day.
Your best posture is your next one. Moving and changing position matters more than a single 'correct' pose.
Most low back pain gets better within a few weeks.
Most low back pain gets better within a few weeks.
Staying active, with simple pain relief if needed, usually helps more than bed rest.
Bed rest is the best treatment for back pain.
Bed rest is the best treatment for back pain.
Bed rest tends to slow recovery; gentle activity is recommended.
Exercise is one of the best ways to prevent back pain coming back.
Exercise is one of the best ways to prevent back pain coming back.
Steffens 2016 (JAMA Intern Med): exercise, with or without education, cut recurrence by about a third.
Slouching causes back pain.
Slouching causes back pain.
Studies find little link between posture and pain. Staying still in any position for too long is more of a problem.
An MRI is needed to understand most back pain.
An MRI is needed to understand most back pain.
Scans often show changes like disc bulges in people with no pain at all, and rarely change treatment.
Lifting with a rounded back isn't as dangerous as once thought.
Lifting with a rounded back isn't as dangerous as once thought.
Research hasn't shown a clear link between lifting style and back pain; building strength matters more.
Standing desks fix back pain.
Standing desks fix back pain.
Alternating sitting and standing helps some people, but standing all day causes its own aches.
Stress and poor sleep can make back pain worse.
Stress and poor sleep can make back pain worse.
Pain is shaped by the nervous system; mood, sleep and worry affect how much it hurts.
Strong glutes and core help protect your back.
Strong glutes and core help protect your back.
They share the load of bending and lifting; trials show strengthening reduces pain in many people.
Smartwatch AF alerts can detect atrial fibrillation in people who don't know they have it.
Smartwatch AF alerts can detect atrial fibrillation in people who don't know they have it.
In the Apple Heart Study (over 400,000 people), about a third of those alerted had AF confirmed on a patch.
Smartwatches count calories burned accurately.
Smartwatches count calories burned accurately.
Heart rate is fairly accurate, but calorie estimates can be off by 20–40% or more.
Sleep trackers can tell exactly how much deep sleep you got.
Sleep trackers can tell exactly how much deep sleep you got.
They estimate stages from movement and heart rate; agreement with lab sleep tests for stages is moderate.
Step counters are generally accurate for walking.
Step counters are generally accurate for walking.
Most phones and watches are within about 10% of actual steps during normal walking.
Tracking trends over weeks is more useful than looking at one day's data.
Tracking trends over weeks is more useful than looking at one day's data.
Single readings are noisy; trends in resting heart rate, HRV and sleep reveal real changes.
AI chatbots can give reliable medical advice.
AI chatbots can give reliable medical advice.
They answer many textbook questions well but can be confidently wrong. Use them to prepare questions for a professional, not to replace one.
If your wearable says you're fine, you don't need check-ups.
If your wearable says you're fine, you don't need check-ups.
Wearables miss many problems, like high cholesterol, early cancers or blood pressure (most don't measure it accurately).
Continuous glucose monitors are proven to help people with diabetes.
Continuous glucose monitors are proven to help people with diabetes.
They improve control and cut low-sugar episodes; benefit for people without diabetes is less clear.
Wearing a tracker makes you more active.
Wearing a tracker makes you more active.
Trials show a modest increase in steps, around 1,000–2,000 a day, which can fade without goals.
Constant checking of health data can increase anxiety for some people.
Constant checking of health data can increase anxiety for some people.
'Orthosomnia' describes people losing sleep worrying about sleep scores.
Air pollution is one of the biggest environmental causes of early death worldwide.
Air pollution is one of the biggest environmental causes of early death worldwide.
Fine particles (PM2.5) are linked to heart disease, stroke, lung cancer and dementia.
Morning daylight helps set your body clock.
Morning daylight helps set your body clock.
Light in the first hours after waking strengthens your circadian rhythm and can improve sleep at night.
Indoor light is as bright as daylight.
Indoor light is as bright as daylight.
Indoor light is often 100–500 lux; outdoor daylight is 10,000 lux or more, even on cloudy days.
Bright light at night is linked to worse sleep and metabolism.
Bright light at night is linked to worse sleep and metabolism.
Large UK Biobank studies link more night light exposure to higher risk of diabetes and mental health problems.
Indoor air purifiers improve health.
Indoor air purifiers improve health.
HEPA filters reduce particles and may lower blood pressure slightly; long-term health effects need more study.
Living near green space is linked to longer life.
Living near green space is linked to longer life.
Studies across many countries link more greenery to lower death risk and better mental health.
Noise only matters if it wakes you up.
Noise only matters if it wakes you up.
Traffic noise at night raises stress hormones and blood pressure even when you sleep through it.
Gas cooking can raise indoor nitrogen dioxide levels.
Gas cooking can raise indoor nitrogen dioxide levels.
Good ventilation or extractor fans while cooking reduce exposure.
Extreme heat is mainly risky for older people.
Extreme heat is mainly risky for older people.
Older adults are most at risk, but heat also harms outdoor workers, athletes, babies and people with chronic illness.
Sunlight through a window gives you vitamin D.
Sunlight through a window gives you vitamin D.
Glass blocks most UVB, the rays your skin needs to make vitamin D.
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