Make sure your ticker's in shape before going any further. Each March, more than 15,000 cross-country skiers race 56 miles across the Swedish cou...
Each March, more than 15,000 cross-country skiers race 56 miles across the Swedish countryside. The winner claims a prize worth about $10,000—and a higher risk of irregular heartbeat, according to a new study in the European Heart Journal.
Researchers followed over 50,000 skiers who had completed the race. Compared with those at the back of the pack, skiers who finished fastest had a 30 percent greater risk of developing either bradycardia (a slow heartbeat) or atrial fibrillation (fast and irregular movements in the heart’s top chambers). And athletes who’d done five or more races had a 30 percent greater risk of these conditions than those who’d skied the route only once.
The results confirm what docs have known for a while: “When athletes train heavily in endurance sports, the heart muscle dilates and the pumping chamber thickens,” says Kevin Campbell, M.D., a cardiologist at Wake Heart & Vascular in Raleigh, North Carolina. This enlargement can cause the heart’s atria—or top chambers—to quiver irregularly. And training increases the heart’s efficiency, leading to slower beats.
These types of heart rhythm changes do have dangers. Atrial fibrillation may increase the risk of stroke, chest pain, or heart failure, and bradycardia can cause you to pass out, Dr. Campbell says.
But this is important: The findings shouldn’t deter you from exercising, especially since the skiers had no increase in rates of more dangerous forms of arrhythmia or of sudden death, the study authors say. That said, if you’re highly competitive—or new to serious endurance training—ask your doctor about screenings to check for underlying heart risks, Dr. Campbell recommends.
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