Exercising for health: the merits of lifestyle physical activity.

Abstract

Evelyn Jones (see box below) is similar to 60% of adults in the United States in that she is sedentary most of the time.1 Her cardiovascular health would clearly benefit from a weight-reduction and exercise program. Indeed, moderate weight loss of 5% to 15% of one's body weight produces significant health improvements in overweight and obese persons who are at risk for type 2 diabetes mellitus and coronary heart disease.2,3 The most effective method for long-term weight loss maintenance is a combination of caloric restriction achieved by dietary restriction and increased caloric expenditure through an exercise program. This article presents the health merits of lifestyle physical activity. The focus of this discussion is the value of Evelyn adopting a program of habitual physical activity to improve her cardiac and metabolic health. ​health. Table 1 Case study Evelyn Jones is a 45-year-old black woman who works as a secretary in a large law firm. She has 4 children aged 18, 21, 23, and 25 years. Since her divorce 15 years ago, she has been a single mother. Evelyn is concerned about her weight and her family history of high blood pressure and diabetes. She knows that exercising would be good for her, but she just doesn't have the time. Working full time and being a single parent leaves her feeling exhausted. Evelyn lives in an apartment in an unsafe neighborhood with 2 of her grown children. She is seeing you today for her annual physical examination. Medical history: Her mother died of a stroke at 60 years of age Physical examination: height 5′4″, weight 165 lb (gained 7 lb since last year); blood pressure 138/86 mm Hg (130/82 mm Hg on her last visit). Other findings are unremarkable. Laboratory findings: blood glucose, 126 mg/dL; total cholesterol, 225 mg/dL; high-density lipoprotein, 45 mg/dL; low-density lipoprotein, 142 mg/dL, and triglycerides, 190 mg/dL View it in a separate window THE SCIENTIFIC FOUNDATIONS OF LIFESTYLE PHYSICAL ACTIVITY The traditional exercise prescription of the 1970s and 1980s strove to improve physical fitness (as defined in table 1) by promoting participation in vigorous types of endurance exercise.4 The general belief was that if a person did not exercise within a given heart-rate range or exercise intensity, the benefits of the program would be minimal. In hindsight, it is not surprising that these recommendations did not inspire approximately 85% of American adults to become physically fit.1,2,3,5,6,7 Common barriers to achieving this task include lack of time, the program being “not fun” or “too hard,” and musculoskeletal injury.1,3,5 Consequently, 60% of the American public remains sedentary. Table 1 Physical fitness, physical activity, lifestyle physical activity, and exercise defined16,17,18 Over the last decade, it became apparent that the amount of exercise, especially exercise intensity, needed to produce health benefits is considerably less than the amount needed to improve physical fitness.1,3,6,7 Our work3,8,9,10 and that of others1,6,7,12,13,14 have shown that low-to-moderate intensity physical activity typical of everyday life (table 2) has favorable effects on cardiometabolic health3,15 (see figure 1 for the concept of cardiometabolic disease). These benefits include improved glucose homeostasis, blood lipid-lipoprotein levels, abdominal fat distribution, and blood pressure in the absence of significant gains in physical fitness or substantial weight loss. Figure 1 The Concept of Cardiometabolic Disease3,15 links the disorders of the metabolic syndrome that are predictive of cardiovascular disease and Type 2 diabetes mellitus Table 2 Exercise intensity for middle-aged adults: definitions and distinctions1,25 Physical activity differs from physical fitness in that it is a behavior rather than an attribute (table 1).16 People displaying this behavior engage in movement that expends a range of energy from low to high. Exercise is a subset of physical activity that is planned, structured, repetitive, and intended to enhance or maintain physical fitness; it is also likely to entail sports play. From the recent findings on the health merits of low-to-moderate physical activity has emerged the concept of lifestyle physical activity. Dunn and colleagues have defined lifestyle physical activity as, “the daily accumulation of at least 30 minutes of self-selected activities, which includes all leisure, occupational, or household activities that are at least moderate in their intensity and could be planned or unplanned activities that are part of everyday life.”17 Lifestyle physical activity has deviated from the traditional methods of exercise prescription by advocating accumulated, unstructured activities of daily living according to individual preference and convenience. Lifestyle physical activity may be more successful than structured, more vigorous exercise programs in motivating our predominantly sedentary and overweight society to become physically active on a regular basis. Preliminary findings indicate that lifestyle physical activity programs do indeed increase physical activity levels and are effective in optimizing the cardiometabolic health of middle-aged and older overweight men and women.3,8,9,10,11,12,13,17,18