The approach with the strongest evidence for poor sleep appears on almost no tip list: cognitive behavioural therapy for insomnia, or CBT-I. In a meta-analysis of 20 randomised trials, participants fell asleep about 19 minutes faster and spent 26 minutes less time awake at night (PMID 26054060).
What bothers me about most articles on how to sleep better: 20 or 36 tips stacked up with no ranking at all. A blackout curtain gets the same space as a therapy backed by dozens of trials.
That is not advice. That is a list.
Below, the same measures are ordered by how strong the evidence behind them is. Including the ones that are weaker than their popularity suggests.
How can you sleep better?
The three measures with the most support are simple ones: a fixed rising time, caffeine only in the first half of your day, and less alcohol in the evening. If your complaints last longer than three months, CBT-I carries the strongest evidence. The rest is an add-on, not a foundation.
The order in the table below follows the quality of the research, not the popularity of the tip.
| Approach | How strong is the evidence | Roughly what to expect |
|---|---|---|
| CBT-I (cognitive behavioural therapy for insomnia) | Strong: meta-analysis of 20 randomised trials | Falling asleep about 19 minutes faster and 26 minutes less time awake at night (PMID 26054060) |
| A fixed wake-up time, seven days a week | Fairly strong: a core component of CBT-I, rarely tested alone | A steadier sleep rhythm after two to three weeks; the gain builds slowly |
| Stopping caffeine eight hours before bed | Strong mechanism, small experimental study | 400 mg of caffeine six hours before bed still cost over an hour of sleep (PMID 24235903) |
| Limiting alcohol in the evening | Fairly strong: consistent sleep research | Falling asleep faster, but less REM and more wakefulness after the first half of the night (PMID 23347102) |
| Exercise during the day | Moderate: meta-analysis with small to medium effects | Slightly faster sleep onset and slightly better sleep efficiency (PMID 25596964) |
| A cool, dark bedroom | Weak to moderate: much assumption, little comparative research | A comfort gain; rarely the answer in long-standing insomnia |
| Over-the-counter melatonin | Weak: measured effects are small and vary widely | Usually a difference of a few minutes in sleep onset; questions about it belong with your GP or pharmacist |
The effects in the third column are group averages from research. For you it can be more or less, and sometimes a measure does nothing at all.
What works best against poor sleep?
CBT-I, by a wide margin. It is not therapy about your childhood, but a four to eight week programme. Sleep restriction, stimulus control and tackling worry about sleep form the core. In the Dutch GP guideline, the NHG-Standaard Slaapproblemen en slaapmiddelen, that non-drug approach comes first, ahead of medication.
The meta-analysis by Trauer and colleagues pooled 20 randomised trials (PMID 26054060). Participants fell asleep about 19 minutes faster on average. The time they spent awake in the middle of the night dropped by roughly 26 minutes.
Their total sleep time barely moved, about 8 minutes. That looks disappointing, but it is exactly the point. CBT-I makes your time in bed denser, not longer.
Sleep efficiency rose by about 10 percentage points. That is the share of your time in bed you actually spend asleep.
Sleep restriction is the part where people drop out. You spend less time in bed than you are used to for a while, and the first week feels wrong. That is precisely why guidance helps here.
Thuisarts.nl, the patient information site Dutch GPs point to, describes in plain language how such a programme runs and what your GP can do.
How late can you drink coffee?
Earlier than most people assume. In the study that tested this directly, 400 mg of caffeine six hours before bed still cost more than an hour of sleep (PMID 24235903). That is roughly four cups of coffee. An eight hour margin is therefore more realistic than the familiar rule of stopping after dinner.
Caffeine has a half-life of around five hours in adults. Drink your last cup at 4pm and part of it is still in your blood at midnight.
The most striking detail of that study sits in what the participants believed. In their sleep diaries they noticed little of the difference the measurements did pick up.
That makes caffeine deceptive. You do not feel the effect, so you blame your bad night on something else.
Tea, cola, energy drinks and pre-workout all count. If you want tips for falling asleep, this is the cheapest one: move your last caffeine two hours earlier and watch what happens over two weeks.
Does alcohol help you fall asleep?
For falling asleep yes, for staying asleep no. Alcohol shortens sleep onset and deepens the first hours of your night. After that it suppresses REM sleep and fragments the second half of the night (PMID 23347102). You wake more often between three and six in the morning.
That effect is dose-dependent. It also shows up in people who otherwise sleep fine.
The nightcap is a trade: asleep sooner, worse at staying asleep. Anyone who mostly lies awake in the second half of the night usually recognises this pattern at once.
What REM sleep and deep sleep do sits in our article on deep sleep and how much you need. On that early waking we wrote a separate piece: waking up at night.
What do screens and blue light do to your sleep rhythm?
More than tire your eyes, but less than is often suggested. Participants who read on a light-emitting eReader for four hours saw their melatonin start about one and a half hours later than readers of a printed book. They got less REM sleep and were groggier the next morning (PMID 25535358).
In that same study melatonin output was more than halved. Falling asleep took about 10 minutes longer.
Now the detail that almost never gets mentioned. That was four hours of reading, five evenings in a row, on a screen at full brightness.
Ten minutes of scrolling is a far smaller stimulus than that. I think the late hour itself is the culprit more often than the colour of the light.
A blue light filter therefore probably helps less than putting your phone down half an hour earlier.
Does exercise during the day help against poor sleep?
Yes, but modestly. A meta-analytic review of physical activity and sleep found small to medium improvements in sleep onset, sleep duration and sleep efficiency (PMID 25596964). Regular activity did more for perceived sleep quality than one isolated workout. The gain is real, but smaller than most tip lists promise you.
The effect on deep sleep was clearest after a single bout of exercise in that review.
What too little sleep does to your body over the longer term is covered in our piece on sleep deprivation.
What do sleep hygiene and over-the-counter sleep aids deliver?
A good foundation and a weak treatment. Sleep hygiene, the collective name for fixed times, a cool dark room and no screens in bed, performs worse than CBT-I in head to head research on long-standing insomnia. Something similar holds for an over-the-counter sleep aid: the measured effect stays small.
On bedroom temperature, 16 to 19 degrees is the figure people repeat. Solid comparative research in people with genuine insomnia is thin on the ground.
Melatonin is sold without prescription in the Netherlands, which creates the impression that it is both harmless and effective. The measured difference in sleep onset usually stays within a few minutes. Timing and dose also matter a great deal.
I deliberately do not write here what you should or should not take.
Questions about melatonin, valerian or any other over-the-counter sleep aid belong with your GP or pharmacist. They can also check for interactions with medication you already use.
What strikes me here: being sold over the counter says nothing about the strength of the evidence. The NHG-Standaard Slaapproblemen en slaapmiddelen is in fact restrained about sleep medication.
When is poor sleep a reason to test your blood?
When your sleep hygiene is already right and you stay tired anyway. Persistent tiredness despite enough hours in bed sometimes has a measurable side: thyroid values, iron and ferritin, blood sugar and inflammation markers. A blood test makes no sleep diagnosis. It can make visible causes that a stricter evening routine will not shift.
Picture two people who both sleep 6 hours and are both tired: one has a ferritin of 18 ug/L, the other 95 ug/L.
In the first, a low iron store may play a part in the tiredness. In the second the explanation probably lies elsewhere. Same number of hours, a very different conversation with your GP.
An underactive thyroid, a disturbed blood sugar or low-grade inflammation can also drag your energy down without sleep being the real problem.
Which values matter here is set out in our overview of causes of persistent fatigue and in the article on poor sleep and your blood values. If you sleep enough and are still tired, read tired despite enough sleep.
To have this measured, the fatigue test looks at the values that most often play a role. The extended health checkup looks wider and includes blood sugar and inflammation markers.
A good night of sleep cannot be forced with a gadget. Part of what makes people tired can simply be measured.
Something concrete for the next two weeks. Set your alarm at the same time seven days a week, and note your last caffeine plus your estimated sleep onset. If nothing changes and you stay tired during the day, take those notes to your GP. That is a sharper question than "I can't sleep".
References
- Trauer JM, Qian MY, Doyle JS, Rajaratnam SMW, Cunnington D. Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis. Ann Intern Med. 2015;163(3):191-204. PMID 26054060.
- Drake C, Roehrs T, Shambroom J, Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013;9(11):1195-1200. PMID 24235903.
- Kredlow MA, Capozzoli MC, Hearon BA, Calkins AW, Otto MW. The effects of physical activity on sleep: a meta-analytic review. J Behav Med. 2015;38(3):427-449. PMID 25596964.
- Chang AM, Aeschbach D, Duffy JF, Czeisler CA. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proc Natl Acad Sci U S A. 2015;112(4):1232-1237. PMID 25535358.
- Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB. Alcohol and sleep I: effects on normal sleep. Alcohol Clin Exp Res. 2013;37(4):539-549. PMID 23347102.
- NHG-Standaard Slaapproblemen en slaapmiddelen, with the accompanying patient information on Thuisarts.nl.
This article is informational and does not replace medical advice. Blood values are a snapshot and say nothing about a diagnosis on their own. Every result at Vitalcheck is reviewed by a BIG-registered doctor. If your symptoms persist or get worse, contact your GP.
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