Echocardiography shows that short-term cardiac changes after marathon running are reversible, according to findings published December 10 in JAMA Cardiology.
Researchers led by Michael Schindler, MD, from the University of Zurich in Switzerland, found no significant links between increases in marathon-induced acute troponin T and right ventricular ejection fraction (RVEF) after 10 years of endurance training and competition. While left ventricular ejection fraction (LVEF) and left ventricular diastolic function changed significantly, these values remained within normal limits.
“These data suggest that repetitive strenuous exercise training and endurance competitions did not induce long-term deterioration of right ventricular function in most recreational male endurance athletes,” Schindler and co-authors wrote.
While moderate to vigorous physical activity is beneficial for health and longevity, emerging research suggests that high-volume exercise workloads can have negative cardiac effects. These include right ventricle-associated fatigue, dysfunction, and tissue injury.
Schindler and colleagues pointed out that these studies were cross-sectional in design and contained limited longitudinal data. The researchers studied right ventricular remodeling by using real-time 3D echocardiography on volunteers immediately after a marathon and after 10 years of repeated high-level exercise for endurance training. Their goal included determining associations between this level of exercise and marathon-induced increases in troponin T level.
Final analysis included 152 male runners with an average age of 43 years. The runners underwent complete echocardiography exams that included the following: M-mode, B-mode, color, pulsed, continuous wave, and tissue Doppler analysis.
RVEF declined significantly from the prerace to immediate postrace (median, 52.4% and 47.6%, respectively; p < 0.001) assessment and one-day postrace (median, 50.7%; p = 0.001). However, it recovered at three days postrace (median, 51.3%; p = 0.18). RVEF also recovered to the prerace level even at the 10-year follow-up (median, 51.9%; p = 0.15).
LVEF decreased from a median 59.6% to 57.6% immediately postrace (p < 0.001), while the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity (as an index of left ventricular filling pressure) increased from a median 5.1 to 5.4 (p < 0.001) at the 10-year follow-up.
The researchers also reported no association between exercise-induced troponin T increase after the marathon with RVEF and LVEF changes at 10-year follow-up. This included Pearson correlation coefficients of −0.10 for RVEF (p = 0.35) and −0.09 for LVEF (p = 0.35).
Based on their findings, the authors suggested that exercise-associated increases in plasma troponin T “appear to be more benign in general and similar to those in skeletal muscle injury.”
As for the mild decline in LVEF, the authors suggested that this is age-related, considering that diastolic function was also altered at the long-term follow-up.
Read the full study here.