Correlation between fasting heart rate and fasting plasma glucose level in rural Indians

Type of funding sources: None.

Diabetes mellitus is associated with abnormal autonomic function. Diabetes and impaired fasting glucose are associated with increased mortality, particularly from cardiovascular causes. Several factors, including fast heart rate, have been identified to be associated with an increased likelihood of having diabetes. Heart rate is a crude index of the autonomic nervous system tone, reflecting a balance of sympathetic and parasympathetic inputs, and correlates with muscle sympathetic nerve activity and noradrenaline serum levels . Examining its potential role in diabetes risk could improve our understanding of the pathogenesis of diabetes.

Aim of our study was to establish correlation between fasting heart rate and fasting blood glucose level.

509 patients between age group 25 years to 75 years were studied. Resting heart rate was recorded on finger pulse oximeter before taking fasting blood sample. Morning blood samples were obtained by venipuncture after an overnight fast of at least 8 hours and blood glucose estimation done by the hexokinase method. Diabetes mellitus was defined in accordance with American Diabetes Association and World Health Organization guidelines. Pearson"s correlation test was used for statistical analysis.

 We found that resting heart rate was significantly higher in patients with higher fasting blood glucose levels compared with patients with normal glucose levels. This difference was statistically significant with p = 0.002 (r:0.137).

 Our study strongly supports faster resting heart rate as an independent risk factor for incident diabetes and impaired fasting glucose. Meta-analysis of seven published studies confirmed the positive association between resting heart rate and diabetes risks. A resting heart rate is generally considered as a surrogate marker for autonomic activity, and increased sympathetic nerve system activity is associated with both acute and chronic insulin resistance. Sympathetic activation has been associated with many diabetes-related risk factors, including reduced insulin sensitivity, high BP, obesity, subclinical inflammation and the metabolic syndrome. Our findings suggest that this area of investigation may be relevant for future studies.