Mary MacVean / Los Angeles Times

LOS ANGELES — Exercise might work just as well or better than drugs for people with coronary heart disease or recovering from a stroke, according to a review of evidence published Wednesday.

The scientists looked at the outcomes of 305 previous trials with 339,274 participants to try to determine whether physical activity was as effective as drugs at preventing death among people with four conditions: coronary heart disease, rehabilitation from stroke, treatment for heart failure and prevention of diabetes.

There was no difference between exercise and drug interventions for the people with coronary heart disease and for the prevention of diabetes. Exercise was more effective than drugs for recovery from stroke. And drugs, specifically diuretics, were more effective for treatment of heart failure.

Exercise should be considered as “viable alternative to, or alongside, drug therapy,” the researchers said.

The exercise in the research generally took place in structured rehabilitation programs to which patients had been referred by their doctors, said Huseyin Naci, an author of the study who is a fellow at the Harvard Medical School and a researcher at the London School of Economics. The patient’s condition would vary, he said, adding that for people with a prediabetic condition, an exercise program might be more informal.

Naci added in the interview: “The results of our study by no means imply that people should stop taking their medications, especially without consulting their doctors.”

Research is lacking on the potential for exercise to prevent death as compared with drugs, the researchers wrote. Still, they said their “analysis suggests that exercise potential had similar effectiveness to drug interventions with two exceptions. In the case of stroke rehabilitation, exercise seemed to be more effective than drug interventions. In heart failure, diuretics outperformed all comparators, including exercise.”

They called the lack of medical literature a “blind spot” that leaves doctors without evidence of when drugs or exercise or a combination is the best choice.

They called for additional research and noted that their study is limited by the scarcity of studies on exercise interventions and by any limitations of the studies they used.

They were inspired by the well-documented benefits of exercise, including improved health and less likelihood of such things as needing hospitalization.