By Kermit Fernander, Guardian Lifestyles Reporter

kermit@nasguard.com

Is there a male menopause?

Once dubbed by the New York Times as "America's emotional tour guide," Gail Sheehy has done remarkable ground-breaking work in an area that tries to understand many of the changes both males and females undergo as they age.

She first gained notoriety in 1976 with the publication of her bestselling book, "Passages: Predictable Crises of Adult Life". It was such an instant success that it was published again in 1987.

Everyone had, naturally, heard of the menopause in women, but few realized that men have been known to undergo similar (though not identical) physical and emotional changes after the age of 45.

Today medical experts believe these changes in men are linked to the way in which their hormones are functioning or – in some cases – malfunctioning.

"In women, levels of the main female sex hormone, estrogen, remain high for most of their adult lives, and then around the age of 50, plunge over the course of five years. The lower levels of estrogen cause the physical and psychological changes of menopause, including the most obvious one, the cessation of menstrual periods."

With men, the situation is far more gradual and less dramatic. Levels of a man's main sex hormone, testosterone, may begin to drop as early as the age of 30. Instead of plunging over a few years, the levels drop about one percent each year for the rest of his life.

It is the common belief that by 50, 10 percent of all U.S. men have low levels of testosterone. By 70, more than half are testosterone deficient.

The question is, do the progressively lower levels of testosterone cause symptoms in a man that mimic those of lower levels of estrogen in a woman? It's possible, though it may be hard to tell. Here's why: It is said that men with certain rare conditions that cause extremely low levels of testosterone develop a loss of of testosterone develop a loss of muscle mass and bone strength, increased body fat, decreased energy, less interest in sex, erectile dysfunction, irritability and depression.

But before running off to their doctors requesting testosterone replacement therapy to boost sex lives, men need to be aware that while such therapy is advisable in some cases, it is not effective in all cases.

This is because there are many conditions that can cause symptoms associated with testosterone deficiency. They include alcohol abuse, thyroid and other hormonal disorders, liver and kidney disease, heart failure and chronic lung disease. Depression, incidentally, can also cause many of these symptoms in men with perfectly normal levels of testosterone.

Testosterone replacement therapy (TRT) sounds like a great option for men but it does not and cannot solve all problems.