“We know from some very good epidemiological studies,” said Dr. Thompson, “that 150 minutes of moderate exercise each week is clearly associated with improved health outcomes,” including longevity and reduced risk of many diseases. What we don’t know, he added, is whether that will be the case if people rely solely on a few minutes of intense exercise a week.

Though less than half of all the patients were compliant with their blood pressure medication regimens, the patients who got the feel-good phone calls were 17% likelier to be adherent, the study found. These good-feelings exercises may be especially helpful for patients who don't trust the medical system, Dr. Ogedegbe says.