Resting heart rate is the index of cardiovascular health

Abstract

Heart rate (HR) is the most important parameter assessed by all physicians in clinical practice. Usually, it is estimated by clinical examination of the radial pulse. Radial pulse examination, referred to as “nadi pariksha” in ayurveda, was the mainstay of diagnosis of diseases in ancient days. Physiologically HR reflects the state of neural, endocrinal, metabolic and respiratory balances and the state of emotional and psychological being of the individual. HR is profoundly influenced by the neural component, especially the autonomic nervous system (ANS) as sinu‑atrial node (SA node) is innervated by both parasympathetic and sympathetic divisions of ANS. However, at rest, the vagal (parasympathetic) influence on SA node predominates over sympathetic influence. Therefore, resting HR is the index of vagal tone and is considered as an important parasympathetic function test.^[1] Even during the states of activation, such as exercise, emotion and excitement, though tachycardia has been explained by sympathetic activation, vagal withdrawal plays a crucial role in increase in HR. Thus, both in resting and activity states, vagus plays a vital role in the modulation of cardiac pacing.

HR is directly influenced by many hormones such as adrenaline, noradrenaline, thyroxine, dopamine, glucagon, insulin, etc. Body metabolism, via metabolic products and change in body temperature influences HR. Read more...