“Many patients have trouble sleeping after heart bypass surgery,” said study author Dr. Hady Atef of Cairo University, Egypt. “When this persists beyond six months it exacerbates the heart condition and puts patients at risk of having to repeat the surgery. It is therefore of utmost importance to find ways to improve sleep after bypass surgery.”
The study included 80 patients aged 45 to 65 years who had sleep disorders six weeks after heart bypass surgery and who also had reduced functional capacity. All participants were required to perform a six-minute walk test, which measures the distance patients are able to walk on a hard, flat surface. This is a validated way to assess functional capacity. Participants were also asked to complete the Pittsburgh Sleep Quality Index (PSQI) questionnaire, which asks about sleep disorders. An actigraph watch was also worn for 96 hours to monitor rest and activity and track any insomnia during the night.
Patients were then randomly put into two exercise groups. One group was required to do aerobic exercise, and the other was to do a combination of aerobic and resistance exercise. Both groups did 30 exercise sessions in the morning over a 10-week period.
Those in the aerobic exercise sessions walked on a treadmill for 30 to 45 minutes. During the aerobic and resistance exercise sessions, participants walked on a treadmill for 30 to 45 minutes and did a form of light resistance exercise, also known as circuit weight training.
After ten weeks of being on the exercise training protocol, patients were required to complete three assessments again—the six-minute walk test, the PSQI questionnaire, and wearing the actigraph watch for 96 hours. Changes in sleep and functional capacity were then compared between the two exercise groups.
Researchers found that both exercise programs (aerobic exercise alone and combined aerobic/resistance exercise) did improve sleep and functional capacity over the 10-week period. However, isolated aerobic exercise was found to be much more beneficial on sleep and function than the combined program.
Aerobic Exercise Only
“Our recommendation for heart bypass patients with difficulty sleeping and performing their usual activities is to do aerobic exercise only,” said Dr. Atef. “We think that resistance exercise requires a high level of exertion for these patients. This may induce the release of stress hormones which negatively affect sleep.”
“Aerobic exercise means physical activity that does not require a very high level of exertion,” he explained. “Choose an activity you enjoy like walking, cycling, or swimming. Aim for 30 to 45 minutes and do it in the morning because research shows this releases the hormone melatonin which helps us sleep well at night.”