Can Walking 15 Minutes a Day Keep Obesity Away?

Some have recommended that even slight increases in daily physical activity might help prevent weight gain among adults. However, it hasn’t been known how much daily walking is needed to counteract weight gain. The typical basal metabolic rate of a Western adult is 4.2 kilojoules (kJ)/minute and walking slowly expends 3.1 times one’s basal metabolic rate. Thus, walking slowly for 15 minutes uses 197 kJ (100 kcal is 420 kJ).

Two Swiss clinicians used data from the Bus Sante’ survey, an ongoing, community-based surveillance project in Geneva, Switzerland. The survey is designed to monitor chronic disease risk factors among the city’s approximately 100,000 female and 100,000 male, nonhospitalized residents 35 to 74 years of age. Since 1997, the Bus Sante’ survey has included a validated, self-administered quantitative physical activity frequency questionnaire to measure total and activity-specific energy expenditures, with special attention on light- and moderate-intensity activities.

Epidemiologists Alfredo Morabia, MD, PhD, and Michael C. Costanza, PhD, of Geneva University Hospitals, used data from the 1997 to 2001 physical activity frequency questionnaire data to estimate the potential effects of a hypothetical public health campaign to persuade all adults in Geneva to walk at least 15 minutes per day at various recommended intensity levels on the total energy expenditure (Am J Public Health 2004; 94:437).

According to the authors, if the goal is increasing the energy use by 100/kcal per day, the duration of moderate of risk walking should be increased to 30 minutes per day and slow walking should be increased to 60 minutes per day. In addition, to meet the goal of a 100 kcal increase per day would require that at least 50% of the eligible adult population walk briskly each day.