According to researchers, male testosterone levels start declining by 1-2% annually at 30 years. On the other hand, male's quality of sleep starts to fall By 40.

Could there be any relationship between diminished testosterone level and reduced sleep?

Zoran Sekerovic, graduate student at the University of Montreal (UM) Department of Psychology, found a connection between testosterone levels in males aged over 50 and their sleep quality - specifically less deep sleep, that is, Phases III and IV of the slumber cycle.

"Deep sleep is when the recuperation of body and mind is optimal," Sekerovic said.

In youngsters, deep sleep makes up 10-20% of total sleep. By 50 years, it comes down to just 5-7%. For males aged over 60, it can disappear altogether.

The research didn't locate any link with other parts of the sleep cycle: Falling asleep, Phases I and II, or paradoxical sleep, when most of dreaming occurs.

Zoran explained that males in their 20s don't have such a link as their brain cell circuits are intact.

"With age, there is neuronal loss and the synchronisation of cerebral activity isn't as good, which is why there is a loss of deep sleep. Because deep sleep requires great synchronization. Low levels of testosterone intensify the lack of synchronisation and can explain 20 percent of men's inability to experience deep sleep," he maintained.

Sekerovic also said that falling testosterone levels impact sleep, not vice-versa, as other studies have suggested.

Sekerovic carried out the study under the supervision of Julie Carrier, UM professor of psychology.

Sekerovic presented his study results at the annual conference of the Association francophone pour le savoir (ACFAS). (With Inputs from Agencies)