Researchers in Copenhagen have found that weightlifting may offer more protection against heart disease than cardio exercise does. Their study found that both types of exercise reduced heart fat among obese individuals, but that resistance training was more likely to reduce a certain type of dangerous heart fat that has been linked to cardiovascular disease.
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The team found that a type of heart fat called pericardial adipose tissue was reduced among participants who did weighted exercises such as lunges with dumbbells or weighted push-ups, but not among those who did endurance training with aerobic exercise.
Both types of exercise did reduce levels of another type of heart fat called epicardial adipose tissue, which has also been associated with cardiovascular disease.
Epicardial and pericardial fat drives heart disease
Cardiovascular disease is caused by the accumulation of fatty plaques in arteries (atherosclerosis), something which can be prevented by increasing physical exercise and following a healthy diet.
Obesity, which is caused by a poor diet and lack of exercise, can lead to a build-up of the fatty material or adipose tissue around the heart.
Both epicardial adipose tissue and pericardial adipose tissue are recognized as drivers of heart disease. Epicardial adipose tissue has been shown to promote the build-up of fatty plaques in atherosclerosis and to restrict blood flow around the body.
Less is known about the impact pericardial adipose tissue has on heart function, but the authors of the current study say it has been exclusively associated with cardiovascular risk factors, coronary calcification, and the incidence of coronary heart disease.
According to the World Health Organization, heart disease kills one in three people every day worldwide, which equates to 17.9 million per year.
To reduce the risk of developing cardiovascular disease, the NHS recommends following a healthy diet and engaging in exercise, since both of these lower blood pressure and reduce cholesterol levels.
Cardio versus weightlifting
To investigate the impact that different types of exercise may have on heart fat, Regitse Hojgaard Christensen from Copenhagen University Hospital and team randomly assigned 32 individuals who were obese and did not exercise to 12 weeks of weight training, aerobic exercise, or no change in physical activity. None of the participants had existing heart problems or diabetes.
Each person underwent an MRI scan of their heart at baseline and at the end of the study to assess both epicardial adipose tissue mass and pericardial adipose tissue.
Compared with the control group who did not exercise, the aerobic exercise reduced epicardial adipose tissue mass by 32% and weight training reduced it by 24%. However, any impact on pericardial adipose tissue was only seen in the weight training group, which saw a reduction of 31% compared with the control group.
The resistance exercise training in this study was designed as a 45-minute interval type, medium load, high-repetition, time-based training. Participants performed three to five sets of 10 exercises and the sessions were supervised. This specific exercise intervention alone was effective in reducing both fat depots of the heart.”
Regitse Hojgaard Christensen
The researchers did not try combining the two forms of exercise but emphasized that either type was more beneficial than not exercising at all.
“We did not combine resistance and endurance training, which would have been interesting to reveal their potential additive effects,” they say.
The study does not explain why weight training may be more effective than endurance training, but the authors say that other studies have shown that resistance training is better at increasing muscle mass and basal metabolism.
“We, therefore, speculate that participants doing resistance training burn more calories during the day - also in inactive periods-compared to those engaged in endurance training,” says Christensen.
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A combination of weightlifting and endurance training is best
“Nevertheless, both exercise modalities were associated with reduced epicardial adipose tissue, suggesting that people with specific training preferences or requirements can benefit from both training modalities,” writes the team in the journal JAMA Cardiology.
Chadi Alraeis, director of Interventional Cardiology at Detroit Medical Center’s Heart Hospital, says that while plenty of studies have previously looked at the impact of reducing abdominal obesity, the new study is interesting because it looks specifically at the relationship between exercise and fat around the heart.
Based on the new findings, Alraeis suspects that the optimal way to reduce levels of heart fat is to combine both weight training and endurance training:
Along with the time you spend on the treadmill, you might want to add some work with dumbbells, or some lunges, sit-ups or push-ups. It might even be enough to bring some weights to the office so you can use them there. “
Chadi Alraeis, Detroit Medical Center
Christensen and team say the data highlight the potential preventive importance of different exercise modalities as a means to reduce cardiac fat in individuals with abdominal obesity.
Alraeis concludes by pointing out that although the findings are interesting, it is not known what the implications would be ten years later: “We don’t know if outcomes are really being changed. We need some long-term studies to look at that.”
How much exercise should people do?
The NHS recommends that to stay healthy and reduce cardiovascular disease risk, people should try to be active on a daily basis and do the following:
- Engage in at least 150 minutes per week of moderate-intensity aerobic activity such as cycling or brisk walking. Alternatively, complete 75 minutes of vigorous-intensity aerobic exercise such as running or combine moderate- and vigorous-intensity exercise, for example, by performing 2 x 30-minute runs with 30 minutes of brisk walking, which equates to 150 minutes of moderate-intensity aerobic exercise. A good rule of thumb is that one minute of vigorous-intensity exercise is as beneficial as two minutes of moderate-intensity exercise.
- Carry out resistance training that works on all major muscles (in the legs, arms chest, shoulders hips, back, and abdomen) at least two days per week.
Christensen RH, Wedell-Neergaard A, Lehrskov LL, et al. Effect of Aerobic and Resistance Exercise on Cardiac Adipose Tissues: Secondary Analyses From a Randomized Clinical Trial. (2019). JAMA Cardiol. doi:10.1001/jamacardio.2019.2074.