Just as women go through hormonal changes with aging, men’s bodies change in important ways, too. Testosterone is known as the primary male hormone, and it is responsible for development of the male sex characteristics and the male sex organs. Normal testosterone levels impact virtually every organ in the body, including the brain where it influences libido (sex drive) and mood, and the muscles, where it leads to increased size and strength. Testosterone also plays a critical role in our metabolism, including our risk of diabetes. Low testosterone is defined as a clinical syndrome characterized by low testosterone levels in the blood coupled with symptoms that doctors think are attributable to those low blood levels.
Some of the specific signs of low testosterone that may be easier to identify include low libido, erectile dysfunction (ED), reduced genital stimulation or orgasm, hot flashes, osteoporosis, and reduced male pattern hair growth. Less specific signs of low testosterone include decreased energy, depression, reduced muscle strength, poor concentration or memory, sleep disturbance, and increased body fat. Sometimes these latter symptoms are the key to early identification of a problem.
Low blood levels of testosterone—defined by a blood test showing a value less than 300 nanograms per deciliter of blood (ng/dL)—are believed to be quite common and under-diagnosed. In one study, researchers estimated that low testosterone affects 39 percent of men ages 45 and older who present for primary care checkups. Low testosterone becomes more common with age as well as with other medical conditions like obesity, diabetes, high blood pressure, and dyslipidemia (high triglycerides, low HDL cholesterol). Exercise may increase testosterone a little bit. Men who have the symptoms we discussed should have a testosterone blood test. I also believe that men age 35 and older should probably have a baseline testosterone with their cholesterol profile. I think this is important, because studies show that men with undiagnosed low testosterone tend to die earlier than those with normal values. It is better to identify this early. Doctors can help patients decide if treating low testosterone is the right thing to do.
Low testosterone has been linked to cardiovascular disease. A recent study showed that low testosterone in men with high blood pressure was associated with a higher likelihood of heart attack and stroke. Low testosterone may also signal a need to improve lifestyle habits, particularly by exercising more and losing weight. The experts in the field agree that a normal testosterone level is an integral part of good overall sexual, metabolic, and cardiovascular health.
