Effect of heart rate on the risk of developing metabolic syndrome.

High heart rate and metabolic syndrome are risk factors for cardiovascular morbidity and mortality. The relationship between heart rate and risk of developing metabolic syndrome has not been studied in a large cohort. We examined the relationship between heart rate and the risk of developing metabolic syndrome in individuals who participated in a health evaluation program from 1997 to 2002. Among the 7958 individuals who participated in the program, 1677 were excluded from our study because they were being treated for heart disease or had been diagnosed with metabolic syndrome at baseline examination. A total of 6281 individuals (3789 men and 2492 women, 20-89 years of age) were evaluated. They were categorized according to their baseline heart rate and were followed up for a mean of 47+/-16 months (range: 7-71 months). Over the 5-year period, 619 individuals (9.9%) developed metabolic syndrome. Men with elevated baseline heart rates were more likely to experience metabolic syndrome than were those with normal heart rates. This was not true for female patients. The odds ratio (95% confidence interval) of developing metabolic syndrome among men in the highest quartile for heart rate was 1.725 (1.282-2.320) compared with those in the lowest quartile. Each increase in the heart rate category led to an approximately 1.2-fold increase in the risk of developing metabolic syndrome for men only, even after adjusting for age and lifestyle. Elevated heart rate is a risk factor for developing metabolic syndrome in men.