And those conditions take toll on the heart, study says
THURSDAY, Dec. 11 (HealthDay News) -- A too-fast heartbeat in early adulthood is a warning sign for increased risk of cardiovascular problems decades later on, a Japanese study suggests.
The study of 614 residents of a rural farming community in southwestern Japan found that a heart rate greater than 80 beats a minute during a first examination in 1979 predicted the development of obesity and diabetes, which contribute to heart problems.
The findings, from Kurume University School of Medicine, were published online Dec. 11 in the American Journal of Hypertension.
A fast heart rate is a signal from the sympathetic nervous system, a part of the autonomic nervous system, which is the body's automatic pilot that governs instinctive responses, explained Mercedes Carnethon, assistant professor of preventive medicine at Northwestern University's Feinberg School of Medicine. She found the same rapid heartbeat association in a group of Americans she studied.
"If someone has a consistently fast heart rate, it is because of increased input from the sympathetic part of the nervous system because the body is preparing to respond to stress," Carnethon said. "There is an increase in levels of blood glucose -- essentially because the body is storing energy to prepare for fight or flight, so that predisposes to diabetes."
Carnethon's study followed Chicago residents even longer than the Japanese researchers. "Over a 33-year follow-up, we showed that people with a higher heart rate were more likely to have Medicare claims for diabetes-related conditions," she said.
There's a possible clinical use for the findings, Carnethon said, since doctors routinely listen to the heart rate.
"It is a very simple measure, regularly taken in clinical practice, that could be potentially useful because it suggests where there might be a higher inc
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