Better sleep for athletes: what really drives your recovery

Better sleep is probably the cheapest performance gain available to you. When eleven Stanford basketball players extended their sleep by an average of 111 minutes a night for six weeks, their sprint time dropped from 16.2 to 15.5 seconds and their free-throw accuracy rose by 9 percent (PMID 21731144). No supplement, no new programme. Just more time in bed.

Yet sleep is the one training variable most lifters never track. You log your sets, your grams of protein and your steps. Not your night.

I think that is because sleep feels like something that happens to you. It is not. It is a variable you can steer, and one you partly see back in your blood.

How much sleep do you need when you train?

For adults, the Hersenstichting and Thuisarts, the Dutch brain foundation and GP information service, hold a range of roughly seven to nine hours a night. Train hard and you probably sit at the top of that range, because your body has more to repair. No single number fits everyone: your own need shows in how you function without an alarm.

The international consensus from the American Academy of Sleep Medicine is about long-term health, not about performance in the gym (PMID 26039963). For athletes the bar sits higher than "enough to function".

A practical test: set no alarm on your days off for a week and see how long you sleep. If you consistently sleep nine hours, you are probably running a deficit during the week.

What strikes me as a training partner: people who finally fix their sleep rarely complain about "unexplained" dips in the gym.

Is 6 hours of sleep enough?

For most people, no. Six hours sits below the range Dutch health organisations use, and research shows measurable shifts in metabolism and hormones at that duration. You can feel fine on six hours and still recover worse than you think.

That last part is the tricky bit. Sleep debt makes you worse at judging your own sleep debt. You get used to the feeling and start calling it your normal.

In a classic experiment, healthy young men slept just four hours a night for six nights. Their glucose tolerance fell and their evening cortisol rose (PMID 10543671). That was after six nights, not six months.

So six hours is not an immediate disaster. It is a choice you pay for somewhere, and usually not at the moment you make it.

What does poor sleep do to your recovery?

Poor sleep hits exactly the systems your training depends on: your hormones, your blood sugar regulation, your inflammation level and your nervous system. The effect stacks across days. One short night costs you little; a month of short nights probably costs you a training block.

In young men who slept five hours a night for a week, daytime testosterone values sat lower than in the rested condition (PMID 21632481). Testosterone is not the whole story, but it is the currency strength training pays in.

There is an injury side too. Young athletes sleeping under eight hours a night were about 1.7 times more likely to get injured than those getting eight or more (PMID 25028798). Tired muscles and a slower reaction time stop being abstract concepts when you are under a heavy bar.

Then there is the invisible part: your deep sleep. That is the stage where most growth hormone is released. How that works, and how you protect that stage, is in our piece on deep sleep.

Which sleep tips actually work?

The tips that get you furthest are boring: a fixed rhythm, morning light, no caffeine in the second half of your day, a cool bedroom and less alcohol. They work because they all turn the same dial, your body clock. The rest is decoration.

Thuisarts names regularity and exercise as the core of its sleep advice. Regularity is the most useful one and also the dullest. Nobody sells you a supplement for "get up at the same time every day".

Notice that no supplement appears in that table. That is not an accident.

What alcohol does to your recovery and your liver is covered separately in alcohol and your blood values.

Can you train in the evening without wrecking your night?

Usually yes. For most people an evening session is not a problem, as long as you do not run a heavy workout right before bed and you still get time to cool down. Training in the evening disturbs your night less than long assumed, and moving during the day improves your sleep quality.

The practice is simpler than the theory. Train at 21:00, get into bed at 22:15 with a raised heart rate and a head full of sets, and you will sleep worse. Not because training is bad, but because you skipped your wind-down.

Give yourself at least an hour, preferably ninety minutes, between your last set and your bed. Shower, eat, dim the lights.

If you are sensitive, look at your pre-workout too. A scoop with 200 milligrams of caffeine at 19:00 is still working at midnight for plenty of people.

Can you catch up on sleep at the weekend?

Partly. A long Saturday restores some of your alertness, but it probably does not repay everything you lost during the week, and it shifts your rhythm later. Catching up is an emergency brake, not a strategy.

Picture two lifters, both 32. Both spend five weeknights with six hours in bed, and both sleep nine hours on Saturday and Sunday. On paper they average 6.9 hours a night. Yet one feels wrecked and the other feels fine, because the first pushes his clock two hours later every Monday and the second holds his wake time.

Sleep researchers call that two-hour gap in wake time social jetlag. It is the same effect as a short-haul flight, repeated every weekend.

My advice: take two extra hours spread across the week rather than seven hours on Sunday.

What does poor sleep show in your blood values?

Sleep leaves traces in measurable values. With consistently short nights, your cortisol may sit higher in the evening, your fasting glucose may look less favourable and your testosterone may come out lower. None of those values is a diagnosis on its own. Together they give context for what you feel.

Blood values do not tell you how you slept. They show what is happening in the systems around it, and that is exactly the information a tracker cannot give you.

That last row is not a footnote. A blood test is not a way to detect sleep apnoea. If you snore heavily and feel sleepy during the day, that conversation belongs with your GP, not with a panel.

If you want to see where you stand, our 360 health blood test measures cortisol, glucose and testosterone among others. It gives you a starting point, not a verdict.

How sleep works on your hormones and blood sugar is covered in what poor sleep does to your hormones and blood sugar. If your recovery has been flat for a while, also look at spotting overtraining in your blood values.

What does your tracker actually measure?

Less than the screen suggests. A Whoop, Oura or watch measures movement, heart rate, heart rate variability and skin temperature, then infers a sleep stage from that. In head-to-head research those devices are good at the question of whether you are asleep, and considerably weaker at which stage you are in (PMID 33378539).

That does not make them useless. It makes them a trend meter, not a laboratory.

The full comparison is in sleep tracker versus blood values. What your tracker says about your stages, and where those numbers come from, is in sleep stages explained.

Does sleep quality matter more than sleep duration?

You need both, but duration is the variable you can actually turn. You cannot steer your deep sleep directly; you can steer your bedtime. Eight hours of mediocre quality usually gives you more than six hours of good quality, simply because you complete more cycles.

An average sleep cycle runs about 90 minutes. Sleep six hours and you get roughly four of them. Sleep eight and you get five to six, and those extra cycles happen to be rich in dream sleep.

That is why I find it a shame that trackers put so much weight on your stage percentages. The number you can act on is right there too: what time you got into bed.

Start with the dial you can reach.

Where do you start?

Take two weeks and change one thing: get up at the same time every day, Saturday included. Nothing else. Log how your training feels on a scale of 1 to 10 and watch what happens.

If that works, build on it with light, caffeine and your evening training. If you still sleep badly after eight weeks despite a tight rhythm, that is worth a conversation with your GP.

What happens if you skip those two weeks is in sleep deprivation: the consequences for your training and recovery. And if you wake in the middle of the night for no clear reason, start with waking up at night.

References

1. Mah CD, Mah KE, Kezirian EJ, Dement WC. The effects of sleep extension on the athletic performance of collegiate basketball players. Sleep. 2011. PMID 21731144.
2. Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt on metabolic and endocrine function. Lancet. 1999. PMID 10543671.
3. Leproult R, Van Cauter E. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA. 2011. PMID 21632481.
4. Milewski MD, Skaggs DL, Bishop GA, et al. Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. Journal of Pediatric Orthopedics. 2014. PMID 25028798.
5. Van Cauter E, Leproult R, Plat L. Age-related changes in slow wave sleep and REM sleep and relationship with growth hormone and cortisol levels in healthy men. JAMA. 2000. PMID 10938176.
6. Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015. PMID 26039963.
7. Chinoy ED, Cuellar JA, Huwa KE, et al. Performance of seven consumer sleep-tracking devices compared with polysomnography. Sleep. 2021. PMID 33378539.
8. Hersenstichting. Sleep tips and the sleep cycle. Accessed 2026.
9. Thuisarts. I want to sleep better: sleep advice. Accessed 2026.

Disclaimer

Every blood test result includes a professional assessment by a BIG-registered doctor. This article gives general information and is not a substitute for medical advice. A blood test is a tool to walk into the conversation with your GP better informed, not a diagnosis in itself. For treatment decisions, discuss your results with your GP.