From The Desk Of Clarence Bass
Endurance Training Work Differently
It’s a slow process, but resistance training continues to move toward parity with endurance training for building and maintaining fitness and health.
A study published July 3, 2019, in JAMA Cardiology found that the two forms of exercise burn fat in different parts of the heart.
Lead researcher Regitse Hojgaard Christensen, MD, (University of Copenhagen, Denmark) and 21 colleagues found that endurance and resistance training reduced epicardial (epi is "near") fat mass by 32% and 24%, respectively. While resistance training reduced pericardial (peri is "around") fat tissue by 32%, there was no effect of endurance training.
Epicardial is a layer of fat that surrounds the heart muscle and embeds the coronary arteries, while pericardial fat is located outside of the epicardial tissue.
“Even though the two adipose tissue depots are close, they are different,” Dr. Christensen told TCTMD/The HeartBeat. “They are of a different origin. …While the epicardial tissue shares blood supply with the heart muscle, the pericardial adipose tissue is supplied by other blood vessels in the thoracic [rib] cage.”
Investigating the effect of different forms of exercise on the two types of fat around the heart was an important inquiry.
Less is known about pericardial adipose tissue as a cardiovascular risk factor, said Christensen. Given its lack of direct contact with the heart, pericardial adipose tissue may impact heart function in a more indirect way.
“It is possible that the small study [50 subjects with abdominal obesity were randomly assigned to high-intensity interval training, resistance training, or a no exercise control groups] was the reason for lack of effect of endurance training on pericardial adipose tissue mass,” Christensen continued. Nonetheless, “we know from other studies that resistance training is a stronger stimulus for increased muscle mass and increased basal metabolism compared to endurance training and we speculate that participants doing resistance training burn more calories during the day—also in inactive periods—compared to those engaging in endurance training.”
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Comments from researchers not involved in the study add perspective.
The views of Aaron Baggish, MD (Massachusetts General Hospital, Boston) seem to be getting the most attention, while comments from Dr. Chadi Alraeis, director of Interventional Cardiology at Detroit Medical Center’s Heart Hospital, are more specific and practical. While Dr. Baggish is more disparaging, both of them find the new study interesting and an important addition to the literature.
Dr. Baggish suggests that the lack of meaningful reduction in pericardial fat with endurance training is likely because the study was underpowered. He says a finding one way or the other by one or two people might’ve changed the results. For him, the study should not discourage individuals from endurance activity, or to prioritize resistance training. “The bulk of the literature would suggest endurance activity is really the key,” he said. “Resistance activity is important but not to the level that you should ever choose it as opposed to aerobic-based work.”
Dr. Alraeis finds the study interesting because it looks specifically at the relation between exercise and fat around the heart. He suspects, based on the new study, that the best way to combat heart fat is to do both endurance and weight 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 pushups,” he says. “It might even be enough to bring some weights to the office so you can use them there.”
Finally, he adds that long-term studies are needed to look at the implications of these finding 10 years later. “We don’t know if outcomes are really being changed.”
I find the new study easy to believe. It is well established that RT builds muscle, and that muscle drives metabolism. As Dr. Christensen observes, RT increases muscle mass and stimulates metabolism more than endurance training. Calorie burn goes on longer after weight training than after aerobic training. Each pound of muscle tissue helps your body burn more calories at rest, and this burning process is not limited to the hours after your exercise session. As the size of your muscles increase, your body burns more calories every day.
Best all-around results come from doing both RT and HIIT, as I’ve been doing—and recommending—for decades. (Staying active between workouts is also important.)
See the unique benefits of strength training on the heart: https://www.cbass.com/heartmechanisms.htm
The Christensen study provides one more
reason to do both forms of training.
Dr. Kenneth Cooper, the father
of aerobics, now recognizes the importance of strength training,
September 1, 2019
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