Easy Does It: When Too Much Exercise May Not Be Better

Moderate exercise may lower heart disease and stroke risk more than vigorous exercise

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) More of a good thing isn't always better. And that may apply to exercise and its effects on heart health.

Middle-aged women who got moderate exercise a few times a week were less likely to have a stroke or develop heart disease or blood clots, a new study found.

"Inactive middle-aged women should try to do some activity regularly," advised lead study author Miranda E. G. Armstrong, MPhil, PhD, of the University of Oxford in the UK, in a press statement.

"After reading the paper, my thoughts would be that middle aged women would benefit from just moderate physical activity such as walking, cycling,  gardening and doing household work, and would have a 20 percent decreased incidence of coronary heart disease, cardiovascular disease and vascular thromboembolic events, according to this prospective very well designed study," said Deepika Gopal, MD, a cardiologist at The Heart Hospital Baylor Plano, who was not involved in this research.

In an editorial about this study, Rachel R. Huxley, DPhil, said the study by Dr. Armstrong and team answered some important questions.

"Findings from the current [study] have brought some clarity with respect to the questions of how much, how often, and how hard middle-aged women need to do physical activity to accrue the greatest vascular benefits," Dr. Huxley wrote.

For this study, more than 1 million women aged 50 to 64 answered surveys from Dr. Armstrong and colleagues about how often they were physically active. Three years later, these patients were asked about what type of activity they did, such as time spent gardening, walking, cycling or doing housework.

Dr. Armstrong and team followed the women’s health for another nine years to collect data on whether they had a heart attack, stroke or blood clot.

Compared to women who were not active, those who did moderate activity two or three times a week had a 20 percent reduced risk of heart attack, stroke or blood clot. Walking, gardening and cycling were activities tied to this decreased risk. These researchers defined moderate activity as exercise that raised the heart rate or made the women in the study break a sweat.

Those women who exercised vigorously did not see more heart health benefits than women who got moderate exercise. In fact, very active women had an increased risk of blood clots and problems with blood vessels in the brain.

Dr. Gopal explained that the researchers accounted for body mass index (a measure used to indicate overweight and obesity), smoking and alcohol consumption — all factors that affect cardiovascular health. However, she noted, other factors might partly explain why those in the highest physican activity groups had the same or greater risk of cardiovascular diseases as those who did moderate amounts of physical activity.

"These findings may offer some hope — and perhaps a dash of inspiration — to the estimated 30 percent of adults worldwide who struggle to achieve the recommended levels of physical activity," Dr. Huxley wrote.

Dr. Armstrong and team noted that reductions in blood pressure and body weight, as well as boosting the body's ability to use insulin (the hormone that regulates blood sugar), might be ways in which exercise helps heart health.

The study and editorial were published Feb. 16 in Circulation.

Grants from the UK Medical Research Council and Cancer Research UK funded this research. The authors disclosed no conflicts of interest.

Review Date: 
February 13, 2015
Last Updated:
February 20, 2015