How much does sleep really affect your testosterone?
More than almost any other single input you control. In one controlled study, a week of sleeping under five hours a night lowered daytime testosterone in healthy young men by 10 to 15 percent.
That 10 to 15 percent is worth sitting with. Testosterone drifts down by roughly one percent a year with age. So a rough week of sleep can do to your numbers what a decade of ageing would.[1]
The reason is simple. Most of a man's daily testosterone is released while he sleeps.[1] Cut the night short or break it up, and you shrink the window it is produced in. A second study found the same direction after just five nights.[2]
One bad night is not the story. The running pattern is. A full week of short sleep is what moved those numbers, and recovery sleep pulls them back.
Age sets the baseline. The week you just had sets the rest.
Sleep is the first of the four inputs The Climb tracks, and usually the one with the most leverage. Seeing seven nights of poor sleep laid against everything else is the whole point.
- 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.
- Reynolds AC, et al. Impact of five nights of sleep restriction on glucose metabolism, leptin and testosterone in young adult men. PLoS One. 2012;7(7):e41218.
The Climb puts sleep, alcohol, training and stress in one place, so you can see how your own week adds up.
Get the appThe Climb is not a medical device. It does not diagnose or treat any condition.