Even Mild Exercise May Reduce Mortality in Stable CAD

Potentially giving patients with stable CAD added incentive to get up and move more, new findings show that they can live longer by doing so.

“In our study, regular exercise had a large impact on the risk of death in people with coronary heart disease,” lead author Ralph A.H. Stewart, MD (Auckland City Hospital, New Zealand), told TCTMD in an email. “The greatest benefits of increasing physical activity were in persons who take little or no exercise.”

Stewart and colleagues’ study, published in the October 3, 2017, issue of the Journal of the American College of Cardiology, looked at 15,486 patients with stable CAD from 39 countries who participated in the STABILITY study and completed questionnaires about their exercise habits. The investigators aimed to detect a dose-response relationship between the volume of exercise done on a regular basis and adverse outcomes occurring over a period of about 4 years.

What matters most is to choose a way of exercising which is enjoyed and can be part of usually daily activities. Ralph A.H. Stewart

Physical activity intensity was categorized as mild (easy walking, yoga, tai chi, or mild house work), moderate (fast walking, jogging, aerobics, gardening, bicycling, dancing, swimming, or house cleaning), or vigorous (running, lifting heavy objects, playing strenuous sports or doing strenuous work). Information was collected about how active patients were at work and during leisure time.

Lower All-Cause and CV Mortality

All-cause, cardiovascular, and noncardiovascular mortality declined with increased physical activity, as did MACE. After adjustment, patients in the most-active and intermediate-activity tertiles had 30% and 25% lower total mortality, respectively, than those in the least-active group. Increased exercise did not appear to affect the risk of MI or stroke, however.

Additionally, doubling the amount of exercise per week, even if it was only easy walking, was associated with lower all-cause mortality and cardiovascular mortality, but not MI or stroke. Moving up a category in exercise intensity, such as from mild to moderate, also was beneficial and contributed to lowering total mortality and CV mortality. Although all exercise was beneficial, any vigorous physical activity was associated with the greatest benefits, with those patients having lower all-cause mortality compared with those reporting only mild exercise (P = 0.02).

In subgroup analyses, the association between increased exercise and lower mortality was strongest among patients with dyspnea and in those with a high CHD risk score (a combination of risk factors and biomarkers), suggesting that high-risk patients may benefit the most from being more physically active, the researchers say.

Modest Exercise Better Than None

“The study shows there are likely to be benefits from increasing physical activity, even by a modest amount, particularly in people who are sedentary,” Stewart noted. When counseling patients, exercise should be individualized since many people will not wish to exercise vigorously or are unable to, he advised. “They need to know that more modest-intensity physical activity can be very beneficial, and taking no exercise is very hazardous for health.”

The study did not evaluate whether one type of exercise was more beneficial than another. According to Stewart, all exercise is likely to provide a benefit. 

“What matters most is to choose a way of exercising which is enjoyed and can be part of usually daily activities,” he said.

In an editorial accompanying the study, Thijs M.H. Eijsvogels, PhD, and Martijn F.H. Maessen, PhD (both Radboud University Medical Center, Nijmegen, the Netherlands), say the data provide important insight into preventive strategies for patients with CAD and “suggest that as little as 10 min/day of brisk walking (ie, 3.5 mph) is associated with a 33% risk reduction for all-cause mortality. For those unable to walk at a brisk pace, 15 to 20 min/day at a slower pace (2 to 2.5 mph) will yield similar benefits.”

Importantly, the findings imply that it is possible for patients with stable CAD to cut their mortality risk by being active at levels that are below current recommendations, Eijsvogels and Maessen observe.

“The low volume of this minimal effective dose may stimulate patients to incorporate feasible [physical activity] goals in their daily lives and may also eliminate barriers, such as insufficient time or self-confidence, to become physically active,” they write.