Intense aerobic exercise modulates testosterone levels. Testosterone is the primary male sex hormone. It plays critical roles in reproductive health and contributes to bone and muscle mass accretion. A recent review summarizes the effects of aerobic exercise on testosterone levels.
Aerobic exercise can be defined as physical activity that increases aerobic metabolism – the body’s energy-producing processes that require oxygen. Examples of aerobic exercise include walking, running, swimming, dancing, and other activities that increase heart rate and respiration. Exercise intensity – the physiological demand it creates on the body – is a critical modulator of exercise-induced changes in testosterone concentrations. Intensity is often captured as a percentage of a person’s maximal oxygen consumption (VO2max).
The reviewers highlighted the findings of studies that focused on exercise intensity and testosterone response. In one study, investigators assessed changes in testosterone after low, moderate, or high intensity aerobic exercise on an exercise bike and found that only high-intensity exercise increased testosterone. Another group of investigators found that exercise intensity was the critical determinant in whether testosterone levels increased, especially if the number of repetitions remained constant. The group conducted another study in which runners using a treadmill experienced incremental increases in exercise intensity, ranging from 60 to 100 percent of the runner’s VO2max. They found that the runners' testosterone levels began to increase when the runners reached 90 percent of their VO2max and remained high at 100 percent VO2max. About one hour post exercise, the runners' testosterone returned to baseline levels. The reviewers also described research demonstrating that duration and hydration status influence testosterone levels, as well.
The findings presented in this review suggest that intense aerobic exercise promotes increases in testosterone levels, ultimately influencing reproductive and musculoskeletal health. Learn about other beneficial health effects of aerobic exercise in our overview article
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