How Sleep Affects Testosterone: What the Research Shows
When I wrote about symptoms of low testosterone, poor sleep kept showing up as the lookalike. It makes you tired and flat, and it can also move the hormone itself. So here is the evidence, with its limits. I'm not a doctor, and this is not medical advice.
How does testosterone follow your sleep?
Testosterone is not flat across the day and night. A review in the Asian Journal of Andrology describes the pattern: levels begin to rise when you fall asleep and, in young men, peak around the first REM (dreaming) period. The review says the rise depends on sleep itself, not just on the clock, and that it needs at least about 3 hours of sleep with a normal pattern (Wittert, 2014).
Levels are also higher in the morning than later in the day, which is why guidelines call for an early-morning blood test. I cover that in my guide to getting tested.
What happens when you cut sleep short?
The best-known experiment is a 2011 study in JAMA by Leproult and Van Cauter (JAMA, 2011). Here is how it worked:
- Who: 10 healthy young men, average age 24.
- Rested phase: 3 nights with 10 hours in bed.
- Restricted phase: 8 nights with only 5 hours in bed (12:30 am to 5:30 am).
- Measured: blood testosterone, sampled around the clock on the last day of each phase.
Over the waking day, average testosterone was 16.5 nmol/L after sleep restriction versus 18.4 nmol/L when rested. In the afternoon and evening the gap was a little bigger, 15.5 versus 17.9. The authors summarize the drop as 10% to 15% and compare it with normal aging, which lowers testosterone by about 1% to 2% a year. The men also rated their own vigor lower as the restricted week went on.
The honest reading: this is a very small study of ten young men in a lab, and it ran for about a week. It shows that testosterone responds to sleep loss in that setting. It doesn't tell us what happens to a 45-year-old with a normal life and a few bad weeks.
The picture is not completely uniform either. Wittert's review notes that another study, which restricted sleep during the first half of the night, found no significant change in testosterone.
What about older men and everyday sleep?
A small observational study looked at 12 healthy men aged 64 to 74. Researchers measured their sleep in a lab with polysomnography and at home with a wrist monitor for 6 to 9 days, then pooled three morning blood samples. The amount of nighttime sleep measured in the lab was an independent predictor of morning total and free testosterone (Penev, 2007). In plain words, men who slept more tended to have higher morning testosterone.
The limits are the same, and one more: observational means we can't tell which way the arrow points. Lower testosterone could affect sleep too. And 12 men is a very small group.
Does sleep apnea lower testosterone?
Sleep apnea is when breathing repeatedly stops during sleep. Wittert's review concludes that sleep apnea itself is not the cause of low testosterone. After adjusting for age and body weight, the severity of apnea showed no independent link with testosterone. The link runs through obesity.
The same review found that CPAP, the breathing machine used to treat apnea, had no effect on testosterone in the studies it covered, while weight loss raised testosterone in obese men in proportion to the weight lost. That doesn't mean apnea is harmless. If you snore loudly, wake up gasping or feel sleepy all day, tell your doctor. It is worth checking for its own sake.
How much sleep is enough?
No study I found sets a "testosterone-ideal" number of hours. The general guidance comes from the American Academy of Sleep Medicine and the Sleep Research Society: adults should sleep 7 or more hours a night on a regular basis for good health. They also note that sleeping less than 7 hours regularly is associated with weight gain and obesity, diabetes, high blood pressure and other problems (Watson et al., 2015).
Weight is one possible route from short sleep to lower testosterone, since extra body fat goes with lower levels. That is my reading of the pieces above, not something these studies tested.
What should I do with this?
- Protect your sleep first. Aim for 7 or more hours. It costs nothing and helps with much more than testosterone.
- Don't assume extra sleep will fix a low level. The studies above show what happens when sleep is cut. They don't show that extra sleep raises a low number.
- If you are tired for weeks even with decent sleep, get a morning blood test and talk to your doctor. See how to get tested.
- Fix sleep before you buy a supplement. A booster can't make up for five-hour nights. See whether boosters work at all.
Frequently asked questions
Does lack of sleep lower testosterone?
In a small lab study, ten healthy young men limited to 5 hours in bed for 8 nights had daytime testosterone 10% to 15% lower than when rested. It is a small study in young men, so it shows a link, not what will happen to every man.
How many hours of sleep do I need for healthy testosterone?
No study I found gives a testosterone-specific number. The American Academy of Sleep Medicine recommends 7 or more hours a night for adults, and a review says the nighttime rise in testosterone needs at least about 3 hours of sleep with a normal pattern.
Can sleeping more raise my testosterone?
The studies in this article tested sleep loss, not extra sleep, so they can't say. If your level is low, the next step is a repeat morning blood test and a conversation with your doctor.
Does sleep apnea cause low testosterone?
A review concluded that sleep apnea itself is not the cause. The link runs through obesity: in the studies it covered, weight loss raised testosterone and CPAP did not. Still, tell your doctor if you snore loudly or feel sleepy all day.
Does one bad night of sleep lower testosterone?
The sleep-restriction study I cite used 8 nights of short sleep, so it can't tell us about a single night. Don't read much into one rough night.
Sources
- Leproult R, Van Cauter E. Effect of 1 week of sleep restriction on testosterone levels in young healthy men. JAMA. 2011;305(21):2173-2174. doi:10.1001/jama.2011.710
- Wittert G. The relationship between sleep disorders and testosterone in men. Asian J Androl. 2014;16(2):262-265. doi:10.4103/1008-682X.122586
- Penev PD. Association between sleep and morning testosterone levels in older men. Sleep. 2007;30(4):427-432. doi:10.1093/sleep/30.4.427
- Watson NF, 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;38(6):843-844. doi:10.5665/sleep.4716
Marcus Hale
Writer at The Male Ledger. Not a doctor.
I write about testosterone, energy and vitality after 40, and I link to the studies so you can check my work. Marcus Hale is a pen name; here is why.