The level of testosterone decreases annually by two percent when a male reaches 30 years. At the same time the quality of sleep also decreases day by day after the age of 40. Zoran Sekerovic the graduate trainee from University of Montreal has represented this fact and has said that there is a link between sleep and testosterone level.

Doctor Sekerovic has managed to find out a relationship between testosterone levels and the class of sleep of males. He has said there are few people who actually have the deep sleep after the age of 40. He has also said that deep sleep occurs when the revitalization of body and mind is at its best. Deep sleep characterizes to only 10 to 20 % of entire sleep.

But by the age 50, it reduces to 5 to 7 %. For a person over 60 of age, it can vanish overall. The scientists have clarified that men of age 20 don't have any relationship because their neuronal circuits are unharmed at this period of time. As the age increases the destruction of neurons starts and the management of intellectual activity does not remain well settled.