>Researchers at Baylor College of Medicine found that, in the fall and winter, men's estrogen levels rose while testosterone production fell off.
>The study, presented during a November meeting of the Sexual Medicine Society of North America, suggests that the hormonal balance is slightly skewed toward estrogen in cold winter months.
>The testes make testosterone, which is responsible for the development of male characteristics such as facial hair and a deep voice in addition to muscle and bone growth.
>A drop in production can cause a lack of concentration, low energy, poor sex drive, increased moodiness and sleep deprivation, said Dr. Michael Eisenberg, a study co-author.
He said the Baylor research suggests that men might go through a minor version of this each year as fewer hours of daylight and lower temperatures ramp up the process that converts male hormones to female hormones, or aromatization.
>He said men typically become more sedentary during colder months and put on weight.
>Fat cells, Schmidt said, contain a high concentration of aromatase, the enzyme that converts male hormones into female hormones.
How can negate the effects and what are the best possible ways to get and stay fit during winter?