Posted on May 09, 2013, 6 a.m.
A high heart rate may be an independent risk factor for mortality, among fit men.
A person’s resting heart rate – calculated as the number of heart beats per minute – is determined by an individual's level of physical fitness, circulating hormones, and the autonomic nervous system, with a rate at rest of between 60 and 100 beats per minute considered as normal. Researchers involved in the Copenhagen Male Study, established in 1970-71 to monitor the cardiovascular health of middle aged men at 14 large companies in Copenhagen, tracked the health of about 3,000 male subjects for 16 years. The researchers found that a high resting heart rate was associated with lower levels of physical fitness, higher blood pressure and weight, and higher levels of circulating blood fats. Importantly, the data showed that the higher the resting heart rate, the higher was the risk of death, irrespective of fitness level. After adjusting for confounding factors, a resting heart rate of between 51 and 80 beats per minute was associated with a 40 to 50% increased risk of death, while one between 81 and 90 beats per minute doubled the risk, compared with those with the lowest rate. A resting heart rate above 90 beats per minute tripled the risk. On the basis of their findings, the study authors calculated that every 10 to 22 additional beats per minute in resting heart rate increased the risk of death by 16%, overall.
“High heart rate is risk factor for death, not just a sign of poor fitness, study indicates.” BMJ 2013;346:f2429, 16 April 2013.