Strength training and aerobic exercise affect heart fat mass in different ways



Understanding how different types of exercise affect different fats can help shed light on the beneficial mechanisms of physical activity.

Aerobic exercise and resistance training with weights are both effective in reducing epicardial fat in people with abdominal obesity, but resistance training appears to be a better exercise for reducing body fat. pericardial, according to the results of a new study.

Compared to people who did not exercise, those who engaged in aerobic and resistance exercise had a significant 32% and 24% reduction in epicardial fat tissue mass, respectively. On the other hand, compared to the control group, endurance exercise had no significant effect on pericardial fat tissue mass after 12 weeks, but there was a 31% reduction in pericardial fat mass. in those who engaged in strength training (P

According to the authors, a better understanding of these two types of heart fat and how to target them may be important for risk management. Epicardial fat tissue is metabolically active and is thought to have a direct impact on coronary and heart function given its intimate relationship with heart muscle, while less is known about the effect of pericardial fat mass. on cardiac function.

“It is possible that the small study is the reason for the lack of effect of endurance training on pericardial fat tissue mass,” Regitse Højgaard Christensen, MD (University of Copenhagen, Denmark), told TCTMD. Nonetheless, “we know from other studies that resistance training is a stronger stimulus for increasing muscle mass and basal metabolism compared to endurance training and we assume that participants who do resistance training burn more calories during the day, including inactive periods, compared to those who engage in endurance training.

This theory explaining the differential effects on pericardial fat mass needs to be tested in a future study, however, Christensen said.

Overall, the study provides exploratory evidence that different exercise modalities performed under current exercise guidelines target cardiac fat tissue in addition to the other health benefits of exercise. “It was even without concomitant dietary restriction,” Christensen said. “Therefore, the study highlights that practicing physicians motivate patients at risk for cardiovascular disease to engage in any type of exercise as a preventative measure.”

Metabolically active epicardial adipose tissue

The study, which was published online on July 3, 2019, before being printed in JAMA Cardiology, is a secondary review of a larger randomized exercise intervention study in inactive subjects with abdominal obesity. In this substudy, 50 people were randomized to receive endurance training, resistance training, or the control arm, which did not involve any exercise. Endurance training included three weekly high-intensity interval training sessions on an ergometer for 45 minutes over a 12-week period. Resistance training was designed to include medium loads and high reps performed in three to five sets of 10 exercises. The mass of cardiac adipose tissue was measured by MRI. A total of 39 participants completed the study.

Epicardial fat mass – the layer of fat that surrounds the heart muscle and integrates the coronary arteries – remained unchanged in those who did not exercise, but was reduced by 8 and 6 g from baseline in the endurance and resistance training arms, respectively. Compared with the control group, the reduction with both training programs was statistically significant, but the effect of resistance training versus endurance training on epicardial fat mass was not different (P = 0.58).

Pericardial fat mass was reduced by 10, 15, and 43 g from baseline in the control, endurance, and resistance training arms, respectively. The reduction in pericardial fat mass with endurance training did not differ from the non-exercise group, while the reduction with resistance training was statistically significant compared to the control arm. Compared with endurance training, the pronounced reduction in pericardial fat mass with resistance exercise was statistically significant (P = 0.003).

At TCTMD, Christensen said epicardial adipose tissue, the inner layer of both fat deposits, is believed to secrete inflammatory adipokines that cause atherosclerosis as fat tissue builds up and expands. Recent studies, said Christensen, suggest that epicardial fat tissue may be a novel risk factor for cardiovascular disease and may add additional value when added to current risk prediction algorithms.

“Pericardial adipose tissue is located outside the epicardium. [tissue], “she said.” Even though the two fatty tissue depots are close, they are different. They are of different origin. Epicardial adipose tissue is highly metabolically active, and while epicardial tissue shares the blood supply along with the heart muscle, pericardial adipose tissue is supplied by other blood vessels in the rib cage.

Due to its lack of direct contact with the heart, pericardial fat tissue may impact heart function more indirectly, although less is known about pericardial fat as a cardiovascular risk factor. Christensen said.

Another mechanism for the benefits of exercise

Commenting on the paper for TCTMD, Aaron Baggish, MD (Massachusetts General Hospital, Boston), said the study adds to the list of mechanisms in which exercise confers health benefits. “Exercise is good for you, which we all know,” he said. “We know this moves the traditional cardiovascular disease risk factors in the right direction – blood pressure, cholesterol – but none of it really explains the whole story. So to add the epicardial and pericardial fatty part of the story, as well as the [reduction in] epigastric fat, this is a really interesting finding.

Satyam Sarma, MD (UT Southwestern Medical Center, Dallas, TX), who was also not involved in the research, said the study helps build on current knowledge about the beneficial effects of exercise. on ectopic fat deposits, and shows that “participation in a structured exercise program improves metabolic health”. Like Baggish, he noted that resistance training reduced abdominal fat and waist circumference, but how those reductions translate into improvements in fat distribution around the heart is not well understood.

“It could be that any form of exercise, be it strength training or endurance training, indiscriminately reduces fat in different depots,” Sarma told TCTMD in an email. “Alternatively, it may be that increasing lean muscle mass through endurance training helps promote specific endocrine pathways that preferentially reduce pericardial fat tissue.”

Baggish suggested that the lack of a significant reduction in pericardial fat with endurance training is likely a type 2 error because the study was malnourished. “They have such a small number that when you put some kind of statistical test on them, if one or two people are moving in the wrong direction, it will cause the P the value falls on the wrong side of 0.05 “ he said. “Honestly, after doing a lot of repeated measures studies, if I had a dime for every time the P the value was 0.06, I would be a rich man. If you look at the primary data, the results are pretty clear: any type of exercise, be it resistance or endurance training, does good things when it comes to fat deposition and so on. is a solid addition to the literature.

For Baggish, the study shouldn’t discourage individuals from engaging in endurance activity or prioritizing resistance training. “Most of the literature suggests that endurance activity is really the key,” he said. “Resistance activity is important but not at the level you should ever choose it as opposed to aerobic work.”


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