To the Editor.
—Exercise promotion has become a major disease prevention goal, but unfortunately, many attempts to have various population segments initiate and maintain exercise and activity have had limited success.1 Partly in response to disappointing outcomes, and partly based on empirical studies, guidelines for activity and exercise have been reduced to the accumulation of 30 minutes of moderate activity five times per week. While seemingly well-intentioned, these new guidelines and the public health message they deliver may be problematic and potentially counterproductive from both scientific and public policy perspectives in several ways, including:1. The use of caloric expenditure as a standard. The revised guidelines are partly built around epidemiologic studies showing a relationship between gross measures of caloric expenditure in leisure-time activities and reduced morbidity and mortality.1 However, the most recent data from the Harvard Alumni Health Study clearly show that what is critical for risk
Winett RA. Physical Activity and Public Health. JAMA. 1995;274(7):534-535. doi:10.1001/jama.1995.03530070031017