Fast Beating Hearts Sound Trouble

Cardiovascular risk factors increase in those with high resting heart rates

(RxWiki News) Regular exercise can help lower your resting heart rate and keep your heart working efficiently. High resting rates may mean the heart is overworked and health problems may lie ahead.

Your heart is a muscle and it needs a good workout to stay healthy. Those who exercise typically have lower weight, lower levels of circulating blood fat, lower blood pressure and lower resting heart rates.

Scientists have recently observed that the higher the resting heart rate, the higher the risk of death—even if a person happens to have a high level of fitness.

"Exercise regularly to maintain a healthy heart."

Magnus Thorsten Jensen, MD, in the Department of Cardiology at Copenhagen University Hospital Gentofte in Hellerup, Denmark, and his colleagues wanted to see if heart rate had any bearing on an individual's risk of death, no matter their level of cardiorespiratory fitness.

Dr. Jensen and his team tracked the health of just under 3,000 men for 16 years. Subjects were all part of the Copenhagen Male Study, which was set up in 1970-71 to monitor the cardiovascular health of middle-aged men at 14 large companies in Copenhagen.

At the start of the study, all patients were given a checkup and interviewed about their health and lifestyle, including smoking and exercise status. Doctors assessed their cardiorespiratory fitness using a cycling test that was set at three different levels of exertion.

In 1985-86, just under 3,000 of these original participants were given a further checkup, which included measurements of height, weight, blood pressure, blood fats and blood glucose. Resting heart rate was also recorded.

In 2001, about 16 years later, the researchers checked national Danish registers and discovered that almost four out of 10 of the men (39 percent, or 1,082 participants) had died by that year.

Compared to men with normal resting heart rates, those who had a resting heart rate between 51 and 80 beats per minute had a 40 to 50 percent increased risk of death, according to the authors. A rate of 81 to 90 beats per minute doubled the risk, and more than 90 beats per minute tripled the risk.

A normal resting heart rate for adults ranges from 60 to 100 beats a minute, according to the American Heart Association.

Based on the data, scientists estimated that every 10 to 22 additional beats per minute in resting heart rate increased the risk of death by 16 percent, overall.

When smoking was factored in, they observed that every 12 to 27 additional heartbeats per minute increased a smoker's risk of death by 20 percent.

The researchers were not surprised to find that those who weren’t very active generally had higher resting heart rates, and men who were physically active tended to have lower resting heart rates.

They concluded, however, that regardless of the level of physical fitness, subjects with high resting heart rates fare worse than subjects with lower heart rates.

“This suggests that a high resting heart rate is not a mere marker of poor physical fitness, but is an independent risk factor," the authors wrote.

The study was published online April 17 in Heart and Education in Heart, an international peer-reviewed journal for health professionals and researchers in all areas of cardiology. The Copenhagen Male Study was supported by grants from the King Christian X Foundation, the Danish Medical Research Council, the Danish Heart Foundation and the Else and Mogens Wedell-Wedellsborg Foundation.

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Review Date: 
April 17, 2013