Alternating between low- and high-intensity workouts may be helpful when recovering from a heart attack, based on a recent study that links interval training to weight loss in cardiac rehab patients. Findings were presented at the American College of Cardiology’s 68th Annual Scientific Session and highlight the benefits of interval training in cardiac rehab programs.
Cardiac rehab is recommended for patients recovering from heart attack and other heart problems. It typically includes supervised exercise, help with managing medications and counseling to help patients quit smoking, eat well and reduce stress. Together, these steps help patients recover their health and prevent future heart problems.
However, experts wonder if certain types of exercise training in cardiac rehab may be more effective than others.
To learn more, researchers tested two exercise programs in a 12-week cardiac rehab at the Mayo Clinic. The first was considered standard for cardiac rehab programs, while the second included training that alternated between low and high-intensity exercise.
The study included 120 cardiac rehab patients with an average age of 67 who were recovering from a recent heart attack. A total of 90 patients chose to participate in the interval training, while 30 participated in the standard regimen.
Patients on interval training alternated between one-minute periods of high-intensity exercise (for example, running at a pace that makes it very difficult to talk) and three- to five-minute periods of low-intensity exercise (such as walking at a casual pace) during their sessions. They completed four to eight of these alternating intervals in a session. Patients on moderate intensity training performed 30 continuous minutes of moderate exercise, such as walking or cycling at a pace that is challenging but sustainable.
In total, participants completed three exercise sessions per week for twelve weeks. By the end of the study, patients in the interval training lost about 4 more pounds of body fat, gained about a pound and a half more lean muscle mass, and trimmed about an inch more off their waists, on average, than patients who did the standard regimen. However, there was no significant difference between the two groups in terms of total body weight or BMI.
Findings are promising, as the amount and distribution of body fat affects risk for heart problems, according to authors.
“These findings support the use of high-intensity interval training (HIIT) as an essential treatment tool to improve body composition in heart attack patients enrolled in early outpatient cardiac rehabilitation,” said Yaoshan Dun, MD, PhD, a cardiac rehabilitation specialist at the Mayo Clinic and Xiangya Hospital of Central South University in Changsha, China, and the study’s lead author. “Our data suggest that, compared to moderate-intensity continuous training, supervised HIIT results in greater improvement in these patients. HIIT may contribute to better outcomes for patients with abdominal obesity who have cardiovascular risk factors or established heart disease.”
As the first study to look at the impact of interval training on body composition, authors also note the potential of this regimen for cardiac rehab.
“A considerable amount of research on HIIT has been done in athletes to demonstrate its ability to improve total exercise capacity and sports performance,” Dun said. “Scientists and clinicians are just beginning to recognize the power that HIIT may have in clinical populations to prevent a second heart attack in patients who’ve already had one.”