Sports can influence testosterone levels.
A man’s testosterone levels rise when they’re competing, studies have shown.
For example, after a game, the winner’s testosterone will increase even more. And fans’ hormone levels seem to mirror those of their athletic idols. In a group of 21 men watching a Brazil vs. Italy World Cup match, the Brazil fans’ testosterone levels increased after their team won, but the Italy fans’ testosterone fell.
Fat can lower testosterone.
Obese men tend to have lower testosterone than thinner men, Dr. Dobs says. It’s not clear why, she adds, although one possible reason is that obesity promotes a state of widespread inflammation in the body.
“When there’s fat cells, there’s a lot of inflammatory factors,” she says. “These inflammatory factors have been associated with suppression of testosterone synthesis.”
Testosterone is not the fountain of youth.
It would be great if an aging man’s vigor, muscle power, and sex drive could be restored with testosterone.
But it is not clear whether therapy will do anything for the 75% to 80% of men over 65 who have normal levels of testosterone.
Men with below-normal levels, however, may get a boost in libido, sexual function, and bone mass from supplemental testosterone. And it may help diabetic men with low testosterone build lean muscle mass.
Taking testosterone doesn’t cause prostate cancer.
It has long been thought that taking testosterone increases the risk of prostate cancer. Testosterone treatment can boost levels of prostate-specific antigen, or PSA, a nonspecific marker for prostate cancer, which may lead to more prostate biopsies and more prostate-cancer diagnoses, Dr. Goodman says.
There are now, however, major questions about whether it’s worthwhile to treat—or even diagnose—prostate cancers in older men, given that they’re common and often slow-growing.
Low levels are linked to sleep apnea.
Men with sleep apnea are more likely to have low testosterone, and treating sleep apnea can help return it to normal.
But if a man with sleep apnea is diagnosed with low testosterone alone, taking the supplemental hormone can worsen sleep apnea. That’s why it’s crucial for men with low testosterone to get a thorough workup by an endocrinologist so underlying conditions that can cause low testosterone, such as sleep apnea or pituitary-gland tumors, don’t go undiagnosed, Dr. Goodman says.
Testosterone may hurt men’s hearts.
In 2010, researchers halted a study of testosterone therapy in older men because of a higher rate of cardiovascular problems such as heart attack in the group taking testosterone instead of placebo.
The reason isn’t clear, but caution should be used in prescribing testosterone to older men in poor health, Dr. Goodman says. Declining testosterone in men is associated with health problems, but this doesn’t mean giving older men testosterone will extend lifespans, he says.
Too much may kill brain cells.
It’s only known to happen in a petri dish, but Yale researchers showed that nerve cells exposed to high levels of testosterone were more likely to self-destruct. The hormone boosted a “cell suicide” mechanism known as apoptosis, which, under normal circumstances, is supposed to help the body wipe out cancerous or otherwise abnormal cells.
And the higher the testosterone level in the dish, the shorter lived the cells were. Exposure to low levels of testosterone, however, had no effect on the cells.