The benefits of the drug semaglutide, sold under the brand names Ozempic and Wegovy, seem to go beyond controlling diabetes and helping people shed pounds. New research shows that the drug also has cardiovascular benefits and may lead to a better quality of life for people with heart problems who are also overweight.

In a trial of more than 500 patients with obesity and heart failure in 13 countries, those who got a weekly injection of semaglutide over the course of a year reduced symptoms such as fatigue, shortness of breath, and swelling. They also had notable improvements in their physical abilities and exercise function. The findings were published in late August in the New England Journal of Medicine.

Heart failure is a condition in which the organ struggles to pump enough blood to meet the body’s needs, because it is either too weak or not elastic enough. The patients in this study had a common type of heart failure in which the heart pumps normally but is too stiff to fill properly.

The prevalence of this medical condition has been rapidly rising, says Mikhail Kosiborod, a cardiologist at Saint Luke’s Mid America Heart Institute in Kansas City and lead investigator of the trial. “In addition to increasing the risk of death and hospitalization, it’s a real burden on patients in terms of debilitating symptoms,” he says. People get tired easily and often have trouble doing everyday activities, such as taking a shower, getting dressed, going to the supermarket, and walking.

Kosiborod says there’s growing evidence that obesity is not just coincidental in these patients, but may be the root cause of their heart failure. So researchers turned to semaglutide to see if the drug could alleviate the symptoms by targeting their weight. “What we observed was quite remarkable,” Kosiborod says.

On a 100-point scale commonly used to assess symptoms and quality of life for patients with heart failure, trial subjects taking semaglutide had a nearly 17-point improvement compared to a placebo group, which had an almost 9-point improvement. Patients taking semaglutide lost an average of 13.3 percent of their body weight, compared to a 2.6 percent reduction in the placebo group. They were also able to walk 20 meters (65 feet) farther in a six-minute test used to assess endurance and had fewer hospitalizations and emergency visits during the year-long study period.

Obesity may lead to heart failure in a few different ways. Too much weight gain can cause inflammation, including in the heart. That inflammation can make the heart stiffer and increase the risk of failure. Greater body weight also means more blood volume, which can increase the pressure inside the heart and cause congestion. High blood pressure can also cause the heart muscle to thicken, which can lead to the heart being too stiff to pump enough blood to the body.

Kosiborod says weight loss explains some of the benefits of semaglutide for patients with heart failure, but not all. He says it’s likely that semaglutide is working in other ways that researchers don’t yet fully understand.