SNOWMASS, COLO. – Physical activity is potent medicine, and it doesn’t take all that much of it to derive the maximum cardiovascular benefit: namely, the equivalent of a brisk hour-long walk 5 days/week or jogging at a 10-minute-per-mile pace for half an hour twice weekly, Robert A. Vogel, MD, asserted at the annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
“I’m not telling you to run marathons.said Dr. Vogel, a cardiologist at the University of Colorado at Denver, Aurora, with a longstanding interest in preventive cardiology.
He presented selected highlights from the massive evidence base underlying the recommendations put forth in the current comprehensive U.S. Department of Health & Human Services Physical Activity Guidelines for Americans.
One particularly compelling chunk of evidence comes from a Taiwanese government–funded prospective cohort study of more than 416,000 individuals followed for an average of 8 years. A key finding: 15 minutes of moderate-intensity physical activity daily was associated with a 14% reduction in the relative risk of all-cause mortality and a 19% reduction in death caused by cardiovascular disease, compared with that of inactive individuals. Moreover, each additional 15 minutes of daily moderate exercise further reduced mortality by 4%. These benefits extended across the full age spectrum of both sexes and applied to patients with cardiovascular disease (Lancet. 2011 Oct 1;378:1244-53).
“That’s a very impressive result for modest physical activity,” the cardiologist commented.
Data on more than 50,000 adult participants in the Aerobics Center Longitudinal Study based at the Cooper Clinic in Dallas show that vigorous exercise in the form of running at 6 mph for half an hour twice weekly, or a total of 10 metabolic equivalent of task hours (MET-HR) per week, was associated with a roughly 40% reduction in cardiovascular disease mortality. Importantly, 20, 40, or 50 MET-HR/week of vigorous exercise conferred no further survival benefit (J Am Coll Cardiol. 2014 Aug 5;64:472-81). The same group showed that the sweet spot for moderate physical activity in terms of reduced cardiovascular mortality was brisk walking for an hour daily 5 days/week, for a total of 20 MET-HR, which was also associated with roughly a 40% risk reduction compared to inactivity. At that point the benefit plateaued, with no further mortality reduction noted with additional MET-HR of moderate exercise.
“For more than that, we have no evidence of additional cardiovascular benefit. It’s not going to get you to the Tokyo Olympics, but that’s what we need to be doing,” Dr. Vogel observed.
In another report from the Aerobics Center Longitudinal Study, investigators found that moderate-level cardiorespiratory fitness as defined by METs was associated with a 44% reduction in the risk of sudden cardiac death in men and women after adjustment for potential confounders, while high-level cardiorespiratory fitness was associated with a closely similar 48% reduction in risk. This applied to individuals who were hypertensive, overweight, and/or had poor health status, as well as to others (Mayo Clin Proc. 2016 Jul;91:849-57).