Location matters with body fat. The accumulation of excess fat around the heart can increase the risk of cardiovascular disease. A study by researchers at the University of Copenhagen in Denmark assigned participants to resistance training, high-intensity interval endurance training (HIIT) or no exercise. Results showed that only people who lifted weights decreased the fat lying closest to the heart—specifically, inside the sac that encases the heart (the pericardium).

The scientists compared how the protocols affected two types of fat surrounding the heart. Participants were 50 previously inactive adults with abdominal obesity, and the interventions lasted for 12 weeks.

Adults in the weightlifting group trained for 45 minutes three times per week, doing 3–5 sets of 10 exercises. The cardio training group did 45-minute HIIT workouts three times per week on an indoor cycle. Fat deposits were measured by MRI scan.

By the end of the study, pericardial fat had decreased significantly (by 31%) in resistance-trained participants but not in the HIIT group. Fat outside the heart sac (epicardial fat) improved significantly for both groups—dropping by 32% in the cardio group and 24% in the resistance group.

Limitations of the study included its small size. Study authors suggested that future research could examine the combined effects of resistance and endurance training.

Find the study in JAMA Cardiology (2019; 4 [8], 778–87).