Fitness May be Key for Heart Disease Patients

Heart attack risk lower in coronary artery disease patients with higher physical fitness levels

(RxWiki News) Fitness is important to many people, but new research hints that it might be an issue of life or death to some patients with heart disease.

This new study measured the physical fitness of patients with coronary artery disease who were followed for a number of years.

The researchers found that heart disease patients who were more physically fit had a lower risk of dying than their less fit counterparts.

"Find ways to be active throughout the day."

In coronary artery disease (CAD), plaque builds up in the walls of arteries responsible for supplying blood to the heart. The arteries become hard and narrow and deliver less blood and oxygen to the heart. According to the National Institutes of Health (NIH), CAD is the most common type of heart disease and the leading cause of death in the US for both men and women.

Led by Rupert Hung, a medical student at the Johns Hopkins University School of Medicine, the new study relied on data from The FIT Project, which was executed from 1991 to 2009.  

A total of 9,852 CAD patients were identified by Hung and colleagues. The patients had an average age of 61, and 69 percent were male and 31 percent were African American. 

The researchers looked at whether or not the patients had undergone revascularization surgery, in which blocked arteries are opened up. The researchers also analyzed results of treadmill stress tests to determine physical fitness levels and exercise capacity.

Exercise capacity was measured in terms of metabolic equivalents (METS), a measurement of energy use during a physical activity, achieved during the stress test. Patients were separated into groups based on these scores of less than 6 METS, 6 to 10, 10 to 12 or greater than 12 METS. A higher METS score means a greater exercise capacity, and generally, increased physical fitness.

During the follow-up period, which lasted an average of 11.6 years, the researchers measured deaths, heart attacks and revascularization surgeries among the participants. A total of 3,824 deaths, 1,880 heart attacks and 1,930 revascularizations occurred during this time. 

After analyzing the data, the researchers found that the more physically fit patients faired better.

"We found that each 1 MET increase in a person’s exercise capacity was associated with a 13 percent reduction in risk of death, regardless of whether they had previously had a procedure to open a blocked artery," explained another researcher on the team, John W. McEvoy, also of Johns Hopkins University School of Medicine, in a news release. 

In the same news release, Hung noted that this accounted for a 75 percent lower risk of death among the most fit patients compared to the least fit patients, regardless of their history of revascularization surgery. 

The study authors concluded that their findings reinforce the value of exercise and fitness for both CAD patients who have had revascularization surgery and for those who have not.

"This study gives more credence to the importance of exercise for all of us, whether we have suffered a heart attack or not," Sarah Samaan, MD, cardiologist and physician partner at the Baylor Heart Hospital in Plano, Texas, told dailyRx News.

"Some people might believe that once a heart attack or blockage has occurred, exercise is not likely to be of use, and perhaps could even be harmful. However, this study should help encourage people to exercise and stay fit to the best of their ability," said Dr. Samaan, who was not involved in this study.

"A 75 percent reduction in heart attack risk was seen in the most fit vs the least fit individuals. To put that into perspective, the effect of exercise is more powerful at lowering heart attack risk than most prescription drugs," she explained.

"Anyone who has heart disease or who has been sedentary should check in with their doctor before starting an exercise program. Aim for at least 2.5 hours per week of moderate intensity exercise. If you're new to working out, start slowly and build up your endurance gradually," she said.

The study was presented November 17 at the American Heart Association’s Scientific Sessions in Dallas, Texas. It is important to note that studies presented at conferences are considered preliminary until published in a peer-reviewed journal.

Review Date: 
November 14, 2013