Study: Better Athletes Have More Heart Arrhythmias

Irregular heartbeats were more common among the top performers in an extreme cross-country ski race.
RTXC7RSmain.jpg
Athletes compete in the world's longest cross-country ski race. [Reuters]

PROBLEM: Extreme endurance athletes, like long-distance runners, bikers, and even cross-country skiers, tend to have enlarged hearts. Also known as "Athlete's Heart," the condition may be associated with an increased risk of heart problems. Within this already elite group, are those who push themselves the hardest even more at risk?

METHODOLOGY: Researchers based in Uppsala and Stockholm studied almost 53,000 cross-country skiers (mostly men) who managed to complete the Vasaloppet -- the longest cross-country ski race in the world -- between 1989 and 1998, and followed up with them through 2005 using national health registry data. They grouped the participants into quartiles based on the number of races they'd completed and their finishing time, excluded anyone with a history of cardiovascular disease, and controlled for age and other factors.

RESULTS: Those who completed five or more races in a ten-year period, or who placed among the top 25 percent of finishers, increased their risk of developing some form of cardiac arrhythmia -- either an irregular, abnormally fast, or too slow heartbeat -- by 30 percent. 

Between each quartile for the number of races completed (from one to five or more), the risk of arrhythmia increased by 10 percent. A similar trend occurred as finishing time decreased, although this did not reach statistical significance. 

IMPLICATIONS: The Vasaloppet's participants, compared, to "average Swedes," have "lower incidence of physical and mental illness, tobacco consumption, fat intake, and higher fiber consumption." But compared to one another, the top performers were more likely to experience heart irregularities than other, still-extreme-but-less-so athletes.

The researchers didn't find any evidence for the athletes being at an increased risk of the most serious forms of heart failure, like cardiac arrest, and don't necessarily recommend that people cut back on the number of 90 kilometer cross-country megaraces they compete in. Nonetheless, the correlation between increased physical activity and increased heart health may not be as straightforward as we'd like to assume. 


The full study, "Risk of arrhythmias in 52 755 long-distance cross-country skiers: a cohort study" is published in the European Heart Journal.

Presented by

Lindsay Abrams is an assistant editor at Salon and a former writer and producer for The Atlantic's Health Channel.

The Man Who Owns 40,000 Video Games

A short documentary about an Austrian gamer with an uncommon obsession

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register.

blog comments powered by Disqus

Video

The 86-Year-Old Farmer Who Won't Quit

A filmmaker returns to his hometown to profile the patriarch of a family farm

Video

Riding Unicycles in a Cave

"If you fall down and break your leg, there's no way out."

Video

Carrot: A Pitch-Perfect Satire of Tech

"It's not just a vegetable. It's what a vegetable should be."

Video

An Ingenious 360-Degree Time-Lapse

Watch the world become a cartoonishly small playground

Video

The Benefits of Living Alone on a Mountain

"You really have to love solitary time by yourself."

More in Health

Just In