A new study looking at marathon runners, suggesting their hearts may be “stunned” while running the 26.2 miles:
The runners (41 men, 19 women) had normal cardiac function before the marathon, with no signs of troponin in their blood. Twenty minutes after finishing, 60 percent of the group had elevated troponin levels, and 40 percent had levels high enough to indicate the destruction of heart muscle cells. Most also had noticeable changes in heart rhythms. Those who had run less than 35 miles a week leading up to the race had the highest troponin levels and the most pronounced changes in heart rhythm.
