Physical exercise is well known to help to prevent obesity and to benefit cardiometabolic health. A new study in Nature Communications aimed to determine whether physical exercise could reverse cardiac dysfunction caused by a high-fat, high-calorie (HFHC) diet. “We originally wanted to observe a possible cardioprotective effect of physical exercise in HFHC-fed mice,” explains corresponding author Lang Hu. “Unexpectedly, we found a noticeably worse cardiac function in the HFHC-fed mice after undergoing exercise.”

Mice fed a HFHC diet for 8 weeks developed diastolic and systolic cardiac dysfunction, which was not seen in either chow-fed group. MIE exacerbated this dysfunction, and HFHC-fed mice that underwent MIE had worse exercise performance than sedentary HFHC-fed mice or chow-fed mice. MIE with HFHC feeding also led to greater cardiac hypertrophy and fibrosis than HFHC feeding alone.