A Canadian researcher has suggested that as men age, their dropping testosterone levels, 2 percent a year, affect their ability to have deep sleep.

It has been reported that 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.

Deep sleep, Phases III and IV of the slumber cycle, is when recuperation of body and mind is optimal, Sekerovic has said.

It was also reported that 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.

He found no link between the male hormone and sleep phase I and II, or paradoxical sleep, when most dreaming occurs, says Sekerovic.

Sekerovic further says, "The loss of deep sleep is a serious problem that could be treated with testosterone. But hormone therapy can have secondary effects. Therefore, it will be essential to better understand the mechanisms leading to the loss of deep sleep." (With Inputs from Agencies)