By: Reed Humphrey, Ph.D, PT
One of the most important messages that is clear from the scientific literature is that increasing the amount of exercise yields health benefits, including losing weight. Health and fitness professionals also understand that the inverse is true; weight loss attempts without exercise are both less healthful and more likely to fail, when the outcome measure is sustained weight loss. It is, of course, important to ensure the client is expending sufficient calories through exercise to experience enough weight loss to keep them motivated. As a result, moderate intensity exercise is usually the focus of the cardiovascular exercise recommendations, in order to advise a higher overall volume of exercise. This is particularly important for clients for whom lower intensity exercise may be important, and certainly, in the initial phases of weight loss, ensuring regular exercise without risking orthopedic injury is paramount.
Of course, the motivation for weight loss varies between clients. While most clients would include improved health as a desired benefit of their program, most would agree, that achieving an improved aesthetic appearance through a lower body weight is likewise a high priority, and somewhat regrettably, the most important priority in the view of the client. But if health is indeed a priority, and health and fitness professionals have a clear responsibility to communicate that message to clients, fitness also matters.
|There is very compelling emerging science that shows even in the absence of weight loss in the overweight population, improved fitness results in markedly improved health and reduced risk of chronic disease.|
It has been well established that there is a strong relationship between mortality and obesity , and how this is influenced by fitness. (1) In addition, the risk of cardiovascular disease and unstable symptoms increase as a function of elevated body mass index. (2) The effect of fitness on reducing mortality increases linearly with body mass index, (3) and Blair and colleagues showed that death rates are significantly lower in those who are overweight and fit than those who are lean but sedentary. (4) Wessel and colleagues have published impressive data showing that in women, the risk of a major cardiovascular event is reduced in those who are fitter, regardless of whether they were obese or not obese, but this effect was even greater in the obese. (5) In other words, fitness is a much more powerful determinant of health than body weight.
That is not to suggest physical activity without focused improvement in fitness is not important.
An analysis of the data collected in the National Health and Nutrition Examination Survey of nearly 9800 subjects published by Fang in 2003 clearly shows that as physical activity is increased, cardiovascular disease mortality rate by recreational physical activity, and overweight/obesity status is markedly reduced, when adjusted for age and gender. (6) The studies cited here make an important point about the importance of fitness even in the absence of weight loss. Of course, weight loss should naturally occur with regular exercise. It is usually recommended – and emphasized – in most sensible weight loss programs that exercise should be comfortable and at a low to moderate effort level to optimize calories expended, by avoiding fatigue and possible injury. The weekly caloric expenditure should approach 12,000-13,000 calories, and be modified as necessary to meet weight loss goals. Eventually though, there is a logical crossroads between the amount of exercise and increasing the exercise effort, to more efficiently burn calories while improving fitness.
In other words, should one focus on adding more time or distance, or pick up the pace?
The benefit of fitness could be offset by the risk of fatigue and a lower overall caloric expenditure from exercise. Health and fitness professionals should help their clients monitor weight loss but stay in control of their program to minimize this risk while providing significant health benefits. To summarize the important scientific literature, what matters for those trying to lose weight is that once physical activity is a regular part of the plan, eventually tinkering with the program to improve fitness should be a serious consideration to maximize health benefits.
(1) Wei M, Kampert JB, Barlow CE, et al. Relationship between low cardiorespiratory fitness and mortality in normal weight, overweight, and obese men. JAMA 1999;282:1547.
(2) Wolk R, Berger P, Lennon RJ, et al. Body mass index: a risk factor for unstable angina and myocardial infarction in patients with angiographically confirmed coronary artery disease. Circulation 2003;108:2206-2211.
(3) Barlow CE, Kohl HW 3rd, Gibbons LW, Blair SN. Physical fitness, mortality and obesity. Int J Obes Relat Metab Disord Oct 1995;19 Suppl 4:S41-4.
(4) Blair SN, Kohl HW 3rd, Barlow CE, et al. Changes in physical fitness and all-cause mortality. A prospective study of healthy and unhealthy men. JAMA Apr 1995;273(14):1093-1098.
(5) Wessel TR, Arant CB, Olson MB, et al. Relationship of physical fitness vs body mass index with coronary artery disease and cardiovascular events in women. JAMA Sept 2004;292(10):1179-1187.
(6) Fang J, Wylie-Rosett J, Cohen HW, et al. Exercise, body mass index, caloric intake, and cardiovascular mortality.Am J Prev Med 2003;25:283-289.