Walking for the Management of Obesity

Walking during weight reduction leads to modest weight loss, abdominal fat loss, and total fat loss. The response is barely observable at a prescribed level of 150-200 min/wk. Hence, 250-300 min/wk (or 35-45 min daily) seems more suitable for weight reduction purposes. The walking can be split into shorter (10-20 min) periods. There is a dose response between the amount of completed physical activity and weight-loss maintenance. An exercise energy expenditure of 9-10 MJ/wk (2200-2400 kcal), corresponding to walking 70-80 min/day, seems to be associated with stable weight after weight reduction. A smaller amount of walking may slow down, although not prevent, weight regain. Walking studies among people with obesity do not clearly show improvements in lipids or insulin sensitivity. Meta-analyses, including all kinds of physical activities, have shown positive changes in high-density lipoprotein-cholesterol (HDL-C) levels and insulin sensitivity. The amount of exercise, in the absence of weight loss, corresponding to improvements of insulin sensitivity, is around 4.2 MJ/wk (walking 150-180 min/wk). A greater amount of exercise may be needed to improve lipoprotein profiles. The minimum recommended amount of walking for the management of obesity, which is 150-200 min/wk (25-30 min/day or 3500 steps/day added above the basal, sedentary daily activity of 5000-7000 steps/day), may improve insulin sensitivity and cardiorespiratory fitness; however, a significant effect on weight should not be expected. Increasing the duration of walking to 250-300 min/wk (35-45 min/day or 5000 added steps/day) should lead to beneficial changes in weight and HDL-C. Much more than 300 min/wk of walking may be needed to prevent weight regain after substantial weight loss. Cross-sectional studies suggest that a combination of walking and vigorous exercise activity is optimal for weight management and the prevention of cardiovascular deaths. Moreover, individuals who are able to maintain their weight loss long-term expend almost 30% of physical activity energy in vigorous activities. Perhaps high-intensity activities are also needed to increase the total physical activity to efficacious levels for the management of obesity.