Being physically fit may not only reduce your risk of having a heart attack but can also improve your chances of surviving if you do have one, a new study suggests.
The findings, based on an examination of medical records of more than 2,000 men and women, are published online by the journal Mayo Clinic Proceedings.
“We knew that fitter people generally live longer, but we now have evidence linking fitness to survival after a first heart attack,” says Michael Blaha, assistant professor of medicine at Johns Hopkins University School of Medicine.
“It makes sense, but we believe this is the first time there is documentation of that association.”
“Our data suggest that doctors working with patients who have cardiovascular risk factors should be saying, ‘Mr. Jones, you need to start an exercise program now to improve your fitness and chances of survival, should you experience a heart attack,’” says Clinton Brawner, a clinical exercise physiologist at Henry Ford Health System.
The scientists studied medical records of individuals who had taken a treadmill stress test before their first heart attack.
They used each patient’s metabolic equivalent score (MET) as a quick, although not perfect, measure of energy consumption at rest and during physical activity. The higher the MET score, the more physically fit the participants are considered to be.
MET scores range from 1 to 12, where 1 is considered the equivalent of sitting on the couch, 3 aligns with walking, 7 with jogging, 10 with jumping rope, and 12 with sprinting.
The 634 people with MET scores of 10 or higher had about 40 percent fewer deaths after a first heart attack than the rest of the patients.
One-third of the 754 patients with a MET score of 6 or less died within a year of their first heart attack.
Overall, the results show an 8 percent reduction in death risk for each whole-number increase in MET score after a first heart attack.
The researchers used data from the Henry Ford Exercising Testing Project, the so-called FIT Project, following patients who took exercise stress tests between 1991 and 2009 at Henry Ford Hospital in Detroit.
Henry Ford Health System adopted electronic medical record-keeping much earlier than most health systems, says Blaha, and included pharmacy and insurance information in the data.
The 2,061 patients in the study were an average of 62 years old; 38 percent were female and 56 percent were white.
The investigators noted that their study design has limitations, including the fact that they could not assess whether improving fitness levels as measured by MET scores can decrease the risk of death from a heart attack.
Also, Blaha says, they didn’t determine if people who are fitter have less damaging heart attacks, or if they have same-sized heart attacks as those who are unfit but survive them better.
Decades of research show that cardiovascular fitness does increase blood flow to the heart and may aid in healing, which is a likely contributing factor to lower mortality rates.
In a 2013 study, Blaha and his colleagues at Henry Ford linked physical fitness to improved overall survival and heart attack prevention in people with already established coronary artery disease, including prior heart attacks.