What You Can Change _. And What You Can't - Martin E. Seligman [159]
31. R. Paffenbarger et al., “Physical Activity, All-Cause Mortality.” This paper is a classic, head and shoulders better in quality than the literature that precedes it.
32. M. McCarthy, “The Thin Ideal, Depression, and Eating Disorders in Women,” Behaviour Research and Therapy 28 (1990): 205–15. See Jeffrey et al., “Prevalence of Dieting Among Working Men and Women,” for dieting statistics. T. Wadden, A. Stunkard, and J. Smoller, “Dieting and Depression: A Methodological Study,” Journal of Consulting and Clinical Psychology 54 (1986): 869–71, find that dieting, when measured from the beginning to the end, decreases depression among obese women who lost forty-five pounds on average. But when looked at from week to week, depression fluctuated wildly, with half the women getting noticeably more depressed occasionally.
33. J. Girgus, S. Nolen-Hoeksema, M. Seligman, G. Paul, and H. Spears, “Why Do Girls Become More Depressed Than Boys in Early Adolescence?” Paper presented at the meeting of the American Psychological Association, San Francisco, August 1991.
34. A. Fallon and P. Rozin, “Sex Differences in Perceptions of Desirable Body Shape,” Journal of Abnormal Psychology 94 (1985): 102–5.
35. The closest any study has ever come concerns lowering blood pressure. If you are obese and your blood pressure is high, even a small amount of weight loss (10 percent of your weight) will probably lower it. See G. Blackburn and B. Kanders, “Medical Evaluation and Treatment of the Obese Patient with Cardiovascular Disease,” American Journal of Cardiology 60 (1987): 55g-58g. What is still unknown is: When the lost body weight returns, how much will blood pressure increase, and what will the health damage be then? In any case, blood pressure is quite a fallible predictor of health.
I find this study methodologically outdated. With what is known about the likelihood of weight regain after dieting, I believe that any claim about health benefit and weight loss can no longer be made on the basis of a “snapshot” study like Blackburn and Kanders’s. The question is not the momentary benefit after dieting, but the net health effect of dieting followed by regaining the weight.
36. S. Blair et al., “Physical Fitness and All-Cause Mortality;” J. Holloway, A. Beuter, and J. Duda, “Self-Efficacy and Training for Strength in Adolescent Girls,” Journal of Applied Social Psychology 18 (1988): 699–719; Paffenbarger et al., “Physical Activity, All-Cause Mortality.”
Again, this is probable but not certain, and I have used the qualifiers seems and probably to describe the beneficial effects on heart disease of taking up exercise. One study involving over eight thousand Swedish men found twice the risk for physically inactive men, which confirms the above studies. But when that study controlled for the factors correlated with exercise (occupation, diabetes, family history of coronary disease, and mental stress), the beneficial effect of exercise, in itself, disappeared. This finding is important because no one has yet done a large-scale random-assignment study of exercise and heart disease. So it is still unknown if exercising will prevent heart attack or if unchangeable factors that correlate with exercising prevent heart attack. See S. Johansson, A. Rosengren, A. Tsipogianni, et al., “Physical Inactivity as a Risk Factor for Primary and Secondary Coronary Events in Goteborg, Sweden,” European Heart Journal 9 (supplement L) (1988): 8–19.
Dr. Ralph Paffenbarger of Stanford University recently reported that it is never too late to take up exercise. Based on a study of 10,000 Harvard alumni, he finds that men who start exercising between ages 45 and 54 live ten months longer, on average, than sedentary men; taking up exercise between ages 55 and 64 adds nine months, starting between 65 and 74 adds six months, and starting between 75 and 84 adds two months. See “Exercise to Live Longer, by 10