As men age, their testosterone levels drop -- a whopping 2 percent a year -- which can affect their sleep quality, a Canadian researcher suggests. More specifically, low testosterone levels can inhibit deep sleep, the time when the body and mind do the most recuperation.
Zoran Sekerovic, a graduate student at the University of Montreal, discovered a link between testosterone levels in men age 50 and older and their quality of sleep, while under the supervision of Julie Carrier, a professor of psychology at the University of Montreal and director of the Chronobiology Laboratory at the Hopital du Sacre-Coeur de Montreal.
Sekerovic says deep sleep -- Phases III and IV of the slumber cycle -- is when recuperation of body and mind is optimal.
Young men have 10 percent to 20 percent of their total sleep in deep sleep, but by age 50 it's down to 5 percent to 6 percent and in men age 60 and older it can disappear altogether.
Sekerovic says he found no link between the male hormone and sleep Phases I and II, or paradoxical sleep, when most dreaming occurs.
"The loss of deep sleep is a serious problem that could be treated with testosterone," Sekerovic says. "But hormone therapy can have secondary effects. Therefore, it will be essential to better understand the mechanisms leading to the loss of deep sleep."
The findings were presented at the annual conference of the association francophone pour le savoir.





