London, Jul 4 (IANS): Just half an hour of morning walk can help heart bypass surgery patients get a sound sleep at night, says a study.

"Many patients have trouble sleeping after heart bypass surgery," said study author 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."

This study investigated the effect of exercise on both sleep and functional capacity. The study enrolled 80 patients aged 45 to 65 years who had sleep disorders six weeks after heart bypass surgery and also had reduced functional capacity.

The patients were randomly allocated to two exercise groups: aerobic exercise or a combination of aerobic and resistance exercise.

Both groups did 30 exercise sessions in the morning over a 10-week period.

During the aerobic exercise sessions, participants 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 circuit weight training, a form of light resistance exercise.

After 10 weeks, changes in sleep and functional capacity were compared between the two exercise groups.

Both exercise programmes -- aerobic exercise alone and combined aerobic/resistance exercise -- improved sleep and functional capacity over the 10-week period.

But isolated aerobic exercise was much more beneficial on sleep and function than the combined programme, according to the study presented on ACNAP Essentials 4 You, a scientific platform of the European Society of Cardiology (ESC).

"Our recommendation for heart bypass patients with difficulty sleeping and performing their usual activities is to do aerobic exercise only," said Atef.

"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."