Physical activity is potentially as effective as many drug interventions for patients with existing cardiovascular diseases and other chronic conditions.
In the few conditions where the life-saving benefits of exercise have been studied, physical activity was often found to be as effective as drugs at reducing the risk of death, according to the first study to aggregate and assess the comparative benefits of drugs and exercise for reducing mortality in a wide range of illnesses.
The study was published online in BMJ on October 1.
“We were surprised to find that exercise seems to have such powerful life-saving effects for people with serious chronic conditions,” said Huseyin Naci, an HMS visiting fellow in population medicine at the Harvard Pilgrim Health Care Institute, and a graduate student at the London School of Economics. “It was also surprising to find that so little is known about the potential benefits of physical activity for health in so many other illnesses.”
The study, conducted in collaboration with John Ioannidis, C.F. Rehnborg Professor in Disease Prevention and Director, Stanford Prevention Research Center, Stanford School of Medicine, found only four conditions where the effects of exercise on reducing mortality had been studied: prevention of severe illness in patients with coronary heart disease, rehabilitation from stroke, treatment of heart failure and prevention of diabetes.
In addition to providing guidance for patients and clinicians about the importance of discussing the potential benefits of exercise, the researchers highlighted the importance of continuing to research the value of exercise for health.
The researchers argue that more trials comparing the effectiveness of exercise and drugs are urgently needed to help doctors and patients make the best treatment decisions. In the meantime, they say exercise “should be considered as a viable alternative to, or alongside, drug therapy.”
“We’re not saying people who have had a stroke should go off their medication and head to the gym,” Naci said, “but having a conversation with their physician about incorporating exercise into their treatment might be beneficial in many cases.”
In the United States, 80 percent of people 18 and older failed to meet the recommended levels of aerobic and muscle-strengthening physical activity in 2011, according to the CDC. What’s more, the average number of retail prescriptions per capita for calendar year 2011 was 12.1, according to the Kaiser Family Foundation.
For the current study, the researchers analyzed the results of 305 randomized controlled trials involving 339,274 individuals and found no statistically detectable differences between exercise and drug interventions for secondary prevention of heart disease and prevention of diabetes.
Among stroke patients, exercise was more effective than drug treatment, while in congestive heart failure diuretic drugs were more effective than all other types of treatment, including exercise.
The authors point out that the amount of trial evidence on the mortality benefits of exercise is considerably smaller than that on the benefits of drugs, and this may have had an impact on their results. Of the nearly 340,000 cases analyzed, only 15,000 patients had had exercise-based interventions.
The researchers argue in the paper that this “blind spot” in available scientific evidence “prevents prescribers and their patients from understanding the clinical circumstances where drugs might provide only modest improvement but exercise could yield more profound or sustainable gains in health.”
Despite this uncertainty, the authors claim that based on the available data physical activity is potentially as effective as many drug interventions and more trials to address the disparity between exercise and drug-based treatment evidence are needed.
“What we don’t know about the benefits of exercise may be hurting us,” Naci said.