In brief:Evidence suggests that none of the currently used tranquilizer drugs can be used without risking side effects and/or addiction. Many people have contended that physical exercise relieves anxiety, but until recently no experimental evidence has supported this subjective conclusion. Dr. deVries examined this hypothesis by reviewing available data and surveys of expert opinion and controlled psychological and physiological experiments. He believes that appropriate types, intensities, and durations of exercise can produce a significant tranquilizer effect. Rhythmic exercise such as walking, jogging, cycling, and bench stepping for 5 to 30 minutes at 30% to 60% of maximum intensity was most effective.