But researchers say some men in their 80s manage to maintain testosterone levels usually seen in young men. The reasons behind the large variation in testosterone levels aren’t understood, and researchers say their findings suggest sleep may play a role.
"The results of the study raise the possibility that older men who obtain less actual sleep during the night have lower blood testosterone levels in the morning," says researcher Plamen Penev, MD, PhD of the University of Chicago, in a news release.
Less Sleep, Lower Testosterone
In the study researchers measured morning testosterone levels in 12 healthy men between ages 64 and 74. Their sleep was also monitored over the course of about a week.
The results showed that the amount of sleep the men got was a significantly related to the amount of testosterone in morning blood samples. The more sleep the men got, the higher their testosterone level, and those with less sleep had lower testosterone levels (the range of sleep was four hours to eight hours with an average of six hours).
"Although the findings suggest that how long a person sleeps may be an indicator of age-related changes in important hormone signals in the body, future studies are needed to determine the importance of these relationships for the health of older adults," says Penev.
Sleep experts recommend that adults get between seven and eight hours of sleep per night to maintain optimum health.
The findings appear in the April issue of Sleep.