A study published in the journal Sleep concluded that a correlation exists between quality and duration of nighttime sleep and morning levels of the quintessential male hormone: TESTOSTERONE.

The research, conducted by scientists from the University of Chicago, focused on a pool of men aged 64-74. Those who experienced the best and longest periods of quality sleep each night - as measured by polysomnography over 6-9 days - also tended to exhibit the highest blood testosterone levels in tests the following mornings.

No wonder we fellows are feeling randy after a good night's sleep.

As if you needed another reason to seek more restful slumber