Many of the changes that define the aging process are a decline in qualities associated with youth and good health, such as endurance, speed and strength. In addition to these physical transformations, aging also brings about hormonal changes, including a reduction in the hormone testosterone.
Testosterone production begins during prenatal development. It is produced within the gonad glands (testes in males and ovaries in females) as well as the adrenal glands. In boys, testosterone levels increase significantly in early adolescence, an event that initiates and directs the process of puberty. Girls also increase their testosterone production at puberty, but to a much smaller degree. Throughout adulthood, men produce higher testosterone levels then women.
Men begin to experience a decline in testosterone levels during adulthood. Some researchers estimate that after age 30, men lose 1 percent of their testosterone every year. Women also produce less testosterone as they get older, particularly as they approach menopause.
For some men and women, testosterone levels can diminish enough to affect their health and quality of life. In aging males, the most common symptoms of low testosterone are:
Interestingly, many of these same symptoms are also associated with low testosterone in women, even though women require significantly less testosterone than men for optimal health.
Testosterone replacement therapy is an option for both men and women to increase their testosterone to normal levels using supplements of synthetic testosterone. This treatment can alleviate many of the symptoms caused by low testosterone, but the effectiveness varies from person to person.
A few studies have been conducted to determine if older men who already have testosterone levels within normal range can feel younger with testosterone replacement therapy. Some participants of these studies reported that the treatments helped them restore muscle tone and feel more energized. Overall, however, the benefits of such treatment in men with healthy testosterone levels are questionable. For these men, more testosterone is not always better.
The connection between aging and testosterone has been established for many years, but the link between diminishing testosterone and several other age-related diseases has only recently come to light. Specifically, men with low testosterone have a higher incidence of:
The reason that low testosterone is so frequently found alongside these other health conditions is currently not well understood.
Alzheimer's is another age-related disease that researchers have found is connected to low testosterone in men. Research data indicate that the risk for Alzheimer's increases as testosterone levels decline. This mechanism is still under investigation, but some studies suggest that low testosterone may promote neuron death in the brain.
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