Why Zebras Don't Get Ulcers: The Acclaimed Guide to Stress, Stress-Related Diseases, and Coping

by Robert M. Sapolsky

Exercise enhances mood and blunts the stress-response only for a few hours to a day after the exercise session. Exercise is stress reducing so long as it is something you actually want to do. Let rats voluntarily run in a running wheel and their health improves in all sorts of ways. Force them to, even while playing great dance music, and their health worsens. The studies are quite clear that aerobic exercise is better than anaerobic exercise for health (aerobic exercise is the sustained type that, while you’re doing it, doesn’t leave you so out of breath that you can’t talk). Exercise needs to occur on a regular basis and for a sustained period. While whole careers are consumed figuring out exactly what schedule of aerobic exercise works best (how often, for how long), it’s pretty clear that you need to exercise a minimum of twenty or thirty minutes at a time, a few times a week, to really get the health benefits. Don’t overdo it. Remember the lessons of chapter 7—too much can be at least as bad as too little.