Is marathon heart damage a myth?
A 10-year-long study debunks the idea that endurance athletes are at risk of long-term heart issues
For years, the long-distance running world has had this nagging question hovering over it: are we slowly wearing out our hearts? The worry didn’t come from thin air. After big endurance efforts, some runners show temporary changes on echocardiograms, and some have a spike in a blood marker called troponin—a protein released into the bloodstream when heart muscle cells are stressed or injured, and one doctors use when they’re assessing possible heart attacks. A new long-term follow-up study, published in JAMA Cardiology, finally tested the part about whether those finish-line blips turn into lasting damage years down the road.
What the new study tracked
Researchers followed 152 male recreational marathon runners (mean age 43) and measured heart function and biomarkers before the race, immediately after, at one day and three days, and again at 10 years.
What happened to the right ventricle
Right after the marathon, something called right-ventricular ejection fraction (RVEF) dropped—the finding that has fuelled concern. The median value went from 52.4 per cent pre-race to 47.6 per cent immediately after finishing. By the next day, it had improved to 50.7 per cent, and by day three it was essentially back (51.3 per cent). Ten years later, it was still stable at 51.9 per cent. The dip showed up, it resolved within days, and it didn’t drift downward across a decade.
Troponin looked scary, but didn’t predict long-term dysfunction
Troponin T rose after the marathon, but the key point is what it didn’t do. The study found no meaningful association between the post-race troponin response and right- or left-ventricular ejection fraction 10 years later. That refutes the idea that a common post-marathon troponin bump is a warning sign of future ventricular damage, at least in runners like the ones studied.
Small changes on the left side stayed within normal ranges
Left ventricular measures shifted slightly in ways that were statistically significant, but the values stayed within normal physiological ranges. It’s a reminder that “changed” doesn’t necessarly mean “damaged.”
The takeaway
This is the kind of long follow-up runners have been missing. In this cohort of recreational marathoners, the heart’s post-race changes were temporary and didn’t translate into progressive ventricular dysfunction over a decade of continued running.
