This article is more than 5 years old. Information may no longer be current.
Running a marathon linked to transient myocardial tissue, function changes
Click Here to Manage Email Alerts
Strenuous exercise, such as running a marathon, can cause reversible myocardial changes including decreased function, diminished perfusion and localized myocardial edema, according to a study published in the Canadian Journal of Cardiology.
Researchers evaluated 20 recreational distance runners aged 18 to 60 years with no known CVD who were scheduled to participate in the Quebec City Marathon. The runners were studied during peak training 6 to 8 weeks before and 48 hours and 3 months after the marathon. All participants also underwent MRI and blood sampling at baseline and 48 hours after the race. Patients who demonstrated decreased left ventricular ejection fraction upon completing the race underwent a third MRI at 3 months.
During peak training, participants exercised an average of 8.1 ± 2.3 hours and ran 62 ± 18 km per week, with a mean maximal oxygen consumption of 53.2 ± 8.3 mL/kg/min.
After the race, global LVEF and right ventricular EF decreased in approximately half of the runners. Those who experienced this decrease had poorer peak training distance, training time and fitness levels than those who did not. Myocardial edema developed in 36% of segments, while 53% of patients had decreased function and 59% had decreased resting perfusion. Among the 10 patients who experienced decreases in LVEF, all had returned to normal levels at the 3-month evaluation.
The researchers concluded that less-fit runners were more susceptible to localized myocardial edema, diminished perfusion and decreased function. Although these changes were reversible, they may contribute to increased cardiac risk during sustained, strenuous exercise, the researchers noted.
“The changes are more widespread among those with lower fitness levels and less training,” Eric Larose, DVM, MD, FRCPC, FAHA, of the Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Canada, said in a press release. “Although no permanent injury was observed in this group of runners, the findings suggest that there may be a minimum fitness level needed beyond which the heart can bounce back from the strain of training and running a long race. Furthermore, these results emphasize the need for proper preparation before recreational distance runners engage in a marathon race.”
Disclosure: The researchers report no relevant financial disclosures.
Click Here to Manage Email Alerts