A decrease in men’s testosterone level is a natural function of aging. For each year over age 30, the level of testosterone in men starts to slowly dip at a rate of around 1 percent annually (Mayo Clinic, 2012). According to the American Diabetes Association (ADA), over 13 million men have low testosterone levels (ADA, 2013).

What does this natural hormonal decrease really mean? What symptoms or side effects accompany a loss of the male hormone? Testosterone helps maintain a number of important bodily functions in men, including:

  • sex drive
  • sperm production
  • muscle mass/strength
  • fat distribution
  • bone density
  • red blood cell production

Because testosterone affects so many functions, its decrease can bring about significant physical and emotional changes.

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Sexual Function

One of the biggest worries faced by men with declining testosterone levels is the possibility that their sexual desire and performance will be affected. As men age, they can experience a number of symptoms related to sexual function that may be a result of lowered levels of this hormone. These include:

  • reduced desire for sex
  • fewer erections that happen spontaneously, such as during sleep
  • infertility

The Cleveland Clinic suggests that erectile dysfunction (ED) is not commonly caused by insufficient testosterone production (Cleveland Clinic, 2009). However, the ADA reports that 70 percent of men with low testosterone levels have erectile dysfunction, while 63 percent have a low sex drive (ADA, 2013). In cases where ED accompanies lower testosterone production, hormone replacement therapy may help rectify the ED (Cleveland Clinic, 2009).

Physical Changes

A number of physical shifts can accompany low testosterone levels. These include:

  • increased body fat
  • decreased strength/mass of muscles
  • fragile bones
  • decreased body hair
  • swelling/tenderness in the breast tissue
  • hot flashes
  • increased fatigue
  • effects on cholesterol metabolism

Sleep Disturbances

Despite that fact that it can cause decreased energy levels, low testosterone can also cause insomnia and other changes in your sleep patterns. Unfortunately, some therapies designed to treat low testosterone can contribute to sleep apnea, which is a serious sleep problem that causes your breathing to stop and start repeatedly.

Emotional Changes

In addition to physical changes, low levels of testosterone can affect you on an emotional level. The condition can lead to feelings of sadness or depression, and an overall decreased sense of well-being. Some people also have trouble with memory and concentration, and lowered motivation and self-confidence.

Don’t Assume

While each of the symptoms above may be a result of a lowered testosterone level, they may also be side effects of normal aging. Other reasons that you might experience some of these symptoms include:

  • a thyroid condition
  • side effects of medications
  • alcohol use

To determine what’s causing these symptoms for you, schedule an appointment with your physician and request a blood test. A blood test is the only sure way to determine your testosterone level. Harvard Medical School (HMS) recommends a goal of a testosterone level of 300 to 450 ng/dL (nanograms per deciliter) for men over 65 years of age, which is the midpoint of the normal range for the age group (HMS, 2004).