Seemingly healthy marathon runners older than 50 may harbour early signs of heart disease that are difficult to distinguish from the effects of endurance training on the heart.
Using magnetic resonance imaging (MRI) scans, German researchers found that these older athletes had heavier left ventricles than the general population. The left ventricle is the main pumping chamber of the heart. Its mass typically increases in response to endurance training, but in some runners this can be an early sign of heart disease.
“It was difficult to differentiate an athlete’s heart from one that had disease,” says Dr. Stefan MÃ¶hlenkamp, the lead study author and a cardiologist at University Hospital in Munich.
In fact, other tests showed the heart’s pumping ability was impaired in these runners, and that deposits had built up in the arteries feeding the heart.
The researchers performed MRI scans on 108 male volunteers between the ages of 52 and 72 years who had completed at least five marathons in the last three years and had no current symptoms or history of heart disease, high blood pressure or diabetes. The scans showed that average left ventricular mass was 141 grams, compared with a normal weight of about 76 grams.
According to MÃ¶hlenkamp, pre-training screening of new endurance athletes doesn’t typically account for problems specific to older runners. Conventional screening only involves a blood pressure check, questions about heart disease in the family or chest pain, listening to the heart and lungs, and possibly an electrocardiogram. But these techniques can miss early potentially life-threatening cardiovascular disease, he says. “You need additional tests to determine this (such as MRI and computed tomography scans).”
MÃ¶hlenkamp adds that exercise is still the best thing anyone can do to prolong and improve their quality of life, but more research is needed on how doctors can safely declare an older person fit for endurance sports.