Regular aerobic exercisers can turn back the heart's clock, according to a study that provides "MRI" evidence of reversible changes in left ventricular mass.
NEW ORLEANS — April 2, 2011 — Regular aerobic exercisers can turn back the heart’s clock, according to the one of the first studies that provides “MRI” evidence of reversible changes in left ventricular mass (LVM), researchers reported here today in news conference at the American College of Cardiology’s (ACC) 60th Annual Scientific Session and ACC.i2 Summit.
“Aging causes the heart to atrophy and stiffen, but regular exercise can reverse that,” said Paul Bhella, M.D., director of echocardiology at John Peter Smith Hospital Fort Worth, and adjunct professor of medicine at University of Texas Southwestern, Dallas, who presented the study, Lifelong Exercise Training Demonstrates a Dose Dependent Effect on MRI Derived Left Ventricular Mass: Implications for Defining Population Norms and Left Ventricular Hypertrophy.
“The key finding of our work is that as we age, we lose muscle mass, and in contrast, if we engage in regular exercise, we build up the function and prevent heart failure. This is an important finding for an aging population,” said Dr. Bhella. The study is “good news” for physicians and will “remind them of the benefits of exercise on LV mass,” he said.
The study found those who exercised the most—six to seven times per week—throughout their adult life “were not only able to preserve this mass, but also build on it, showing heart masses greater than healthy young subjects between 25 and 34 years. If you were sedentary and then later in life, you engage in exercise six to seven times a week, you can have a healthy preservation of left ventricular function (LVF),” Dr. Bhella said.
“If we can identify people in middle age, in the 45-50 year range, and get them to exercise four-to-five times a week, this may go a long way in preventing some of the major conditions of old age, including heart failure,” reported Benjamin Levine, M.D, the lead investigator of the study.
In an observational study that enrolled 121 participants, 59 were recruited from the Dallas Heart Study, which is a Framingham-type study of residents in Dallas County. The second cohort included 62 lifelong exercisers from the Dallas Cooper Clinic Aerobics Center Longitudinal Study, following training patterns of men and women for 25 years.
Researchers counted the number of aerobic exercise sessions (instead of intensity or duration) per week of the exercisers, who were all 65 years or older, and stratified them in to four groups: non-exercisers; casual exercisers (2-3 times a week), committed exercisers (4-5 times a week) and master athletes (6-7 times a week).
All participants had an MRI to measure cardiac mass and also measurements of peak oxygen uptake (Peak VO2.) Average peak VO2 (ml/kg/min) was about 42 for the 25 patients who exercised more six times per week vs about 32 for the 14 subjects exercising two times or less per week.
LVM (g/m2) was about 66 vs 55 for the individuals less active (less than two times per week).
To get a larger picture of how exercise affects the heart, Dr. Bhella said that he would study other measurements such as the “fibrotic content and stiffness.”