Response.

Abstract

Dear Editor-in-Chief: Our findings clearly showed that, among middle-age women, there were significant reductions in risk of hypertension and depressive symptoms among those who reported reaching recommended levels of physical activity through walking and moderate-intensity activities only (4). Risk reductions were slightly greater for the same volume of physical activity, when vigorous activities were reported, but the differences were only significantly greater at the highest volumes of activity. We concluded that, although the addition of vigorous activity may confer slightly greater benefit in terms of risk of these two outcomes, the difference is only significantly greater when the overall volume of physical activity is high. Although we clearly stated that we felt there were limited additional benefits of vigorous activity, in response to our article, Mediano et al. raise the issue of whether we should be prescribing vigorous activity in clinical practice, for three reasons. First, they cite a 17-fold increase in risk of sudden death during vigorous activity (1). Importantly, the absolute risk of death in this physicians’ health study was extremely low (one sudden death per 1.5 million episodes of vigorous exertion), and habitual vigorous exercise attenuated the risk even more. Although another article has shown that risk of a cardiovascular event during high-intensity interval exercise (two nonfatal cardiac arrests during 46,364 h of high-intensity interval training) was much higher than during moderate-intensity exercise (one fatal cardiac arrest during 129,456 exercise hours), the absolute risks were also very low in this cardiovascular rehab setting (6). Hence, we do not feel that vigorous activity should be excluded in a controlled setting or when patients have a history of vigorous exercise. Second, they discuss the risk of musculoskeletal injury, which increases with intensity and amount of exercise. However, the dose–injury relation varies considerably by activity and individual characteristics (3), and those who meet the current activity guidelines through moderate activities or walking have injury rates similar to those seen in inactive people. Hence, we recognize that being active incurs risk, especially in some competitive sports. Our view is that we must weigh up these risks against the multiple physical and mental health benefits of remaining active. Third, on the issue of adherence and compliance, there is evidence that people are more likely to comply with and stick to moderate exercise regimens than to vigorous ones (5). Our view is, however, that meeting patient preferences on how, where, and with whom they would like to be active, and on issues such as location, cost, supervision, time, type of activity, and being active alone or in a group or team, is just as important as meeting patient preferences on issues of intensity, in terms of maintaining activity on completion of controlled intervention studies (2). So should we be recommending vigorous exercise in clinical practice? Mediano et al. are correct in that practitioners must weigh up the risks and benefits. Getting inactive patients to do any exercise is likely to result in health benefits, and helping them to do what they would like to do, and what they can do, will probably reap the greatest rewards. Wendy J. Brown, PhD Toby Pavey, PhD Geeske M.E.E. Peeters, PhD School of Human Movement Studies The University of Queensland St. Lucia, Queensland, Australia Adrian E. Bauman, PhD School of Public Health University of Sydney Sydney, Australia