The researchers have also looked at the differences between women and men.

A test group of 15 men and equal numbers of women participated in the study. After a completed Ironman, the researchers have taken various samples on the body. Before the race, extensive medical examinations were also done. What you have looked at are primarily the factors that explain cardiac and skeletal muscle breakdown after the race.

- It is a huge stress emergency, we do not know what happens if you run such a race often and for a long time. Previous data from participants in the Vasaloppet show that there is a small risk of getting different types of cardiac arrhythmias, says Patric Bergman, an associate professor of sports science at LNU and who is the project leader in the study.

Women's hearts are better protected

The new thing in the study is that it looks different for women and men.

- The study shows that women's hearts seem to be protected to some extent compared to men, they do a little less harm compared to men. Probably due to biological differences between the sexes, explains Patric Bergman.