Better sleep tips: what the studies really measure, ten habits and what a sleep scan shows

In this article you read which sleep habits have really been measured and how large the measured effect of each habit is. That matters, because tips for better sleep come as a list of equal points, while the research puts very different numbers behind them. More than a quarter of people in the Netherlands aged 12 and over said in 2024 that they sleep badly.⁠³ The BioProfile sleep scan measures how much trouble you have from those complaints, and gives you an indication of where you stand today in this area, as the first of the 11 health areas that the full scan assesses. This is not a diagnosis. It is insight, to see where you stand today. And to help you make better choices in your food and your lifestyle. What this scan does not do: point to a cause or make a diagnosis. Only a doctor can do that last one.

Which better sleep tips reach furthest: the same hour every day

In a cohort of 60,977 people who wore a movement monitor for 6.30 years on average, the four fifths with the most regular sleep all had a lower chance of dying than the most irregular fifth (hazard ratios 0.80, 0.75, 0.72 and 0.70), and regularity predicted that chance more strongly than sleep duration.⁠¹ In plain words: the moment you go to sleep weighed more heavily there than the number of hours you slept. Thuisarts gives the same advice, to bed at the same time and out of bed at the same time, with an hour outside a day, especially in the morning.⁠⁴

Coffee, and how early the last cup should be

In 24 studies caffeine gave 45 minutes less total sleep time, a 7% lower sleep efficiency and 12 minutes more lying awake in the night, and coffee with 107 milligrams per 250 millilitres would have to be drunk 8.8 hours before bedtime to avoid a shorter night.⁠² A cup of 125 millilitres contains about 60 milligrams, with 400 milligrams a day as the limit for adults.⁠⁵ So with a bedtime at eleven at night that last cup comes just after two in the afternoon; Thuisarts keeps to a shorter line of 6 hours,⁠⁴ and notes that 1 or 2 cups already give poorer sleep quality.⁠⁶

Alcohol, screens and exercise

In 27 studies in healthy adults, even a low dose of alcohol, up to 0.50 grams per kilogram of body weight or about two standard drinks, disrupted REM sleep, and the effect grew larger with the dose.⁠⁷ Reading on a lit screen about 4 hours before bed made 12 young adults fall asleep almost 10 minutes later than a paper book did, with 55.12% less melatonin in the evening and the start of the melatonin more than 1.5 hours later.⁠⁸ In everyday words: the evening drink costs you the dreaming half of the night, and the screen pushes the signal to go to sleep back.

A network meta-analysis of 86 randomised studies with 7,276 participants found better sleep quality than in the control group for aerobic training (SMD -1.21), strength training (SMD -1.12) and yoga (SMD -0.82), with an optimum at around 920 MET minutes a week, which is about an hour of exercise a few times a week.⁠⁹

Staying asleep, and waking at around three in the morning

A meta-analysis of 1.1 million people found that complaints about falling asleep and staying asleep (9.6 to 19.4% of adults) were more common than a short sleep duration (6.5% slept less than 6 hours).⁠¹⁰ So the broken night is reported more often than the short night, and none of the sources checked measures one single hour of the clock. Thuisarts names as causes stress and worries, evening habits such as the phone, coffee and alcohol, and mental health problems; the tips for sleeping better with stress and a busy head are going to bed and getting up at the same time and a calm last half hour.⁠^6,4

10 tips for better sleep

1. An hour outside a day, preferably in the morning.⁠⁴
2. To bed at the same time and out of bed at the same time.⁠^4,1
3. Spend at most 8 hours in bed.⁠⁴
4. No caffeine in the 6 hours before sleep,⁠⁴ and 8.8 hours to be sure.⁠²
5. Count milligrams instead of cups: 200 at a time is the limit for adults.⁠⁵
6. Screens away 1 or 2 hours before sleep.⁠^4,8
7. Television off half an hour before sleep.⁠⁴
8. No heavy meal in the 2 hours before, and a calm last half hour.⁠⁴
9. Exercise: aerobic, strength or yoga, around 920 MET minutes a week.⁠⁹
10. Keep the evening glass low: two glasses already disturb REM sleep.⁠⁷

What a sleep scan measures, and what the scan does not measure

The sleep scan asks about your nights over the past two weeks and gives you an indication of where you stand today, with the reading band your answers fall into. Repeat the scan in two weeks and you have two measurements instead of a memory. What a questionnaire cannot do is tell the causes apart: stress, evening habits, coffee, alcohol and mental health problems all read the same in a list of questions.⁠⁶ The scan is not a diagnosis. Are the sleep tips not helping enough? Then Thuisarts says: make an appointment with your GP.⁠⁴ If you already wake up tired, that is where it starts: why you wake up tired.

In summary

If you want to sleep better with tips, know that those tips do not all weigh the same. To bed and out of bed at the same hour reached furthest in the research, caffeine and alcohol are the two you can shift tonight, screen light in the evening pushes your timing back, and exercise shows up in sleep quality. A sleep scan gives you a starting value. It is not a diagnosis, and a doctor is the one you go to if the advice is not enough.