Get High for Health
During the running craze of the 1970s, you heard a lot about something called the runnerís highóitís a feeling of euphoria and relaxation that occurs shortly after a run. Sports scientists attributed the effect to the bodyís increased production of natural painkilling chemicals called endorphins. Later studies, however, repudiated that theory. Those studies often used drugs such as naltrexone, to block the effects of endorphins, but the runnerís high continued to appear after exercise. Scientists then decided that the runnerís highóa concept later extended to weight trainingówas the result of an increased release of catecholamines, such as norepinephrine.
If you secrete more catecholamines during an intense workout, your tolerance for pain will be higher, and so will your ability to train harder. A recent study with rats found that endorphins not only are beneficial for mental and painkilling effects but also may be a major factor in the cardiovascular benefits offered by exercise.†
The rats ran on a treadmill for four days, with one day of highly vigorous exercise. Another group of rats didnít exercise. Heart attacks were then induced in the rats, and the heart damage in the exercised rats was half that of the sedentary rats. The protective effect of exercise was gone five days after the exercise. When rats were injected with a drug that blocks endorphins, the heart-protective effect of exercise disappeared. Exercise also increased the amount of several opiate, or endorphin, genes in the heart, along with genes that regulate inflammation and muscle cell death in the heart.
The conclusion was that much of the protection against cardiovascular disease offered by exercise was due to an increase of endorphin activity in the heart and that the protection was short-lived in the absence of regular exercise.