What Lifting Weights Does to the Harmful Fat Around Your Heart

As people exercise, start to eat more healthfully, and drop some pounds, they may experience slimming around the waistline, but there’s another kind of fat reduction that’s just as important—whittling down fat surrounding the heart.

Now, a new study published in JAMA Cardiology suggests that strength training may be one of the best ways to do it.

First, a quick anatomy review: You have two main kinds of cardiac fat tissue. Epicardial fat tissue surrounds the heart muscle and the coronary arteries. Pericardial fat tissue is outside of that on-the-heart epicardial tissue.

Even though they’re snuggled up together, each tissue type has different properties. For example, the epicardial kind shares blood supply with the heart. Pericardial gets its blood boost from other blood vessels.

Because of its direct contact with the heart and shared blood supply, epicardial fat tissue has been consistently associated with increased risk of cardiovascular disease. Less is known about the risks associated with pericardial fat, since it lacks direct contact with the heart, but experts believe it may affect coronary and heart function in a more indirect—but likely still significant—way.

Which brings us back to the new study.

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Researchers in Denmark held a randomized clinical trial involving 50 people with abdominal obesity, to find out if both endurance and resistance training could affect epicardial and pericardial fat tissue.

Participants were separated into three groups: High-intensity interval training (HIIT) three times a week, resistance/strength training three times a week, or no exercise. The program ran for 12 weeks.

Both exercise groups bettered their VO2 max, while only the resistance training group increased their strength. Those in the endurance and resistance training groups also significantly reduced epicardial fat tissue by 32 percent and 24 percent, respectively.

As for pericardial fat? Endurance training had no effect on it, but resistance training sure did: Participants in that group saw a 32 percent reduction in that kind of heart fat.

While the findings seem exciting, it’s too early to turn the research into specific clinical guidelines, according to lead study author Regitse Højgaard Christensen, M.D., Ph.D.(c) of Copenhagen University Hospital.

But, she added, the study is interesting since it provides new evidence that different exercise types can affect cardiac fat tissue in different ways, especially without any diet changes undertaken at the same time.

The reduction of both types of cardiac fat seen with resistance training but not with endurance training was a surprise, Christensen said.

One explanation might be that resistance training stimulates more muscle mass and increased basal metabolism, or the number of calories needed to keep your body functioning at rest, she noted. And more muscle means more calorie burn for an extended period after working out. It’s possible this could act as a kind of cardiac fat burner, set on simmer.

The best strategy, though, would be to combine the two to some degree on a consistent basis—on one hand, endurance training showed more significant increase in the reduction of epicardial fat, but resistance training, which decreased both kinds of fat, also increased strength, too.

“The takeaway message is that people should be motivated to engage in any type of exercise as a preventive measure, given that cardiac adipose tissue is an emerging cardiovascular risk factor,” Christensen said.

From: Runner’s World US

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