How sleep improves your health, and 7 habits that help you get more of it

Sleep is the first thing most of us cut when the day runs out, and the last thing we think of as health care. The research says that's backwards. This article covers how much sleep adults need, what happens when you run short, the habits with real evidence behind them, and the signs that poor sleep needs a doctor rather than a new pillow.

How much sleep do you need?

At least 7 hours a night, regularly. That's the joint recommendation of the American Academy of Sleep Medicine and the Sleep Research Society, reached in 2015 after reviewing the evidence on sleep and health. Some people need more, and very few people need less, however used to it they feel. Regularity matters too: going to bed and getting up at roughly the same times, weekends included, is part of good sleep, not a bonus.

What short sleep does

You catch more colds. In a 2015 study, healthy adults were given cold virus through nasal drops and watched for a week. Those who'd slept under 6 hours a night in the week before were about 4 times more likely to get a cold than those sleeping more than 7. We cover this in our immune system guide, because no food undoes it.

You get hungrier. When young men were limited to 4 hours in bed for 2 nights, their appetite-calming hormone leptin dropped by 18%, the hunger hormone ghrelin rose by 28%, and they reported 24% more hunger, with cravings leaning towards sweet and starchy foods. If you're trying to manage your weight, sleep is part of the plan.

Your mood and focus suffer. Irritability, poor concentration and a shorter fuse with stress are the most familiar effects, and they show up after a single bad night.

Over years, the risk adds up. A 2010 analysis pooling 16 studies and over 1.3 million people found that regularly sleeping too little was linked to a higher risk of dying over the follow-up period. Very long sleep was linked too, which is usually a sign of an underlying illness rather than a reason to sleep less. These are observational studies, so they show a link, not proof that sleep alone is the cause.

7 habits that help

A 2015 review of the research on "sleep hygiene" found that the individual habits have different levels of evidence, and that they work best together. These are the ones with the most behind them.

1. Keep the same wake-up time. Every day, weekends included. It anchors your body clock more than bedtime does.
2. Stop caffeine 6 hours before bed. In a 2013 trial, a large dose of caffeine (about 2 to 3 strong coffees' worth) taken 6 hours before bed still disrupted sleep measurably, and the researchers recommend at least 6 hours. For a 10 pm bedtime, that means no coffee after 4 pm.
3. Don't use alcohol as a sleeping aid. It helps you fall asleep, then breaks up the second half of the night. A 2013 review of the research found this pattern consistently.
4. Get daylight in the morning, and dim the lights at night. Light is the strongest signal your body clock has.
5. Keep the bedroom cool, dark and quiet. And use it for sleep. If you're lying awake for more than about 20 minutes, get up, do something calm in low light, and go back when you feel sleepy.
6. Move during the day. Regular exercise helps sleep; a hard session right before bed can do the opposite for some people.
7. Finish eating 2 to 3 hours before bed. Especially if you get reflux: lying down on a full stomach makes it worse. Our acid reflux guide covers this in more detail.

Sleep after 40

Many women find sleep changes in their 40s and 50s. Night sweats and hot flushes during perimenopause and menopause wake people up, and lighter sleep with more waking becomes common with age. The habits above still apply, and a cooler bedroom helps more than most people expect. If night sweats are waking you most nights, it's worth talking to your doctor: there are effective treatments, and you don't have to put up with it. Our menopause guide covers the wider picture.

When poor sleep needs a doctor

• Loud snoring with pauses, gasping or choking, or waking unrefreshed however long you sleep. These can be signs of sleep apnoea, which is common, under-diagnosed and treatable.
• Insomnia most nights for 3 months or more. The first-choice treatment isn't a sleeping pill: it's cognitive behavioural therapy for insomnia (CBT-I), a short course of structured sessions. A 2015 analysis of 20 trials found it produced clinically meaningful improvements. Ask your GP about a referral to a psychologist trained in it.
• Low mood, worry or racing thoughts keeping you awake. Sleep and mental health affect each other both ways. Our guides on reducing stress and nutrition and mental health are a start, but persistent symptoms need a professional.
• Restless, uncomfortable legs in the evening, or falling asleep during the day without meaning to.

Where collagen fits

Collagen is rich in glycine, an amino acid that has been studied for sleep quality in a few small trials. It's a modest, early-stage finding, not a sleeping aid, and it won't outdo the habits above. We go through what the studies did and didn't show in does collagen improve your sleep? If you already take collagen, an evening scoop in a warm drink is a pleasant way to use it.

Frequently asked questions

Can I catch up on sleep at the weekend?
Partly. A lie-in pays back some of the debt, but a big swing in wake-up time unsettles your body clock and can make Sunday night worse. An extra hour is better than an extra 3.

Are naps good or bad?
A short nap of 20 to 30 minutes early in the afternoon is fine for most people. Long or late naps can make it harder to fall asleep at night.

What should I eat before bed?
Ideally nothing heavy for 2 to 3 hours. If you're hungry, something small works: a glass of warm milk, a banana or a few nuts. No single food will fix poor sleep.

Should I take melatonin?
In South Africa, melatonin is a scheduled medicine: a pharmacist can supply a low dose for jet lag, and other uses need a prescription. It helps most with jet lag and body-clock problems, less with ordinary insomnia. Ask your pharmacist or doctor, especially if you take other medicines.

The sources

• Watson NF et al. (2015). Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep 38:843–844. View →
• Prather AA et al. (2015). Behaviorally assessed sleep and susceptibility to the common cold. Sleep 38:1353–1359. View →
• Spiegel K et al. (2004). Sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Annals of Internal Medicine 141:846–850. View →
• Cappuccio FP et al. (2010). Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 33:585–592. View →
• Irish LA et al. (2015). The role of sleep hygiene in promoting public health: a review of empirical evidence. Sleep Medicine Reviews 22:23–36. View →
• Drake C et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine 9:1195–1200. View →
• Ebrahim IO et al. (2013). Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research 37:539–549. View →
• Trauer JM et al. (2015). Cognitive behavioral therapy for chronic insomnia: a systematic review and meta-analysis. Annals of Internal Medicine 163:191–204. View →

Find out more

• Does collagen improve your sleep?
• How to reduce stress naturally: 5 habits that hold up
• Foods that support your immune system
• Fasting: what it can and can't do
• 6 health benefits of staying hydrated

This article is general information, not medical advice. If poor sleep is affecting your day-to-day life, or you have any of the warning signs above, see your doctor.

Also in Health