How Exercise Helps Us Tolerate Pain
Written by Editor   
Friday, August 22, 2014 04:53 PM

Regular exercise may alter how a person experiences pain, according to a new study. The longer we continue to work out, the new findings suggest, the greater our tolerance for discomfort can grow.

For some time, scientists have known that strenuous exercise briefly and acutely dulls pain. As muscles begin to ache during a prolonged workout, scientists have found, the body typically releases natural opiates, such as endorphins, and other substances that can slightly dampen the discomfort. This effect, which scientists refer to as exercise-induced hypoalgesia, usually begins during the workout and lingers for perhaps 20 or 30 minutes afterward.

A new study this month found that after six weeks, volunteers in the control group showed no changes in their responses to pain.  But the volunteers in the exercise group displayed substantially greater ability to withstand pain. Their pain thresholds had not changed; they began to feel pain at the same point they had before. But their tolerance had risen. They continued with the unpleasant gripping activity much longer than before. Those volunteers whose fitness had increased the most also showed the greatest increase in pain tolerance.

The results “suggest that the participants who exercised had become more stoical and perhaps did not find the pain as threatening after exercise training, even though it still hurt as much,” an idea that fits with entrenched, anecdotal beliefs about the physical fortitude of athletes.

The study cannot explain just how exercise alters our experience of pain, although it contains hints. Pain thresholds and tolerances were tested using people’s arms, while the exercisers trained primarily their legs. Because the changes in pain response were evident in the exercisers’ upper bodies, the findings intimate that “something occurring in the brain was probably responsible for the change” in pain thresholds.

The results remind us that the longer we stick with an exercise program, the less physically discomfiting it will feel, even if we increase our efforts, as did the cyclists here. The brain begins to accept that we are tougher than it had thought, and it allows us to continue longer although the pain itself has not lessened.

The study also could be meaningful for people struggling with chronic pain. Although anyone in this situation should consult a doctor before starting to exercise, he said, the experiment suggests that moderate amounts of exercise can change people’s perception of their pain and help them, he said “to be able to better perform activities of daily living.”