Sympathetic hyperactivity in children of hypertensive parents

Hypertension is a global problem. Positive family history of hypertension is one of the risk factors for being hypertensive in future life for their children. Hyperactive sympathetic nervous system is reported in children of hypertensive parents. The main objective of the study was to observe the magnitude of alterations in autonomic reactivity following the standard autonomic function tests in normotensive male offsprings of both-hypertensive and normotensive parents. Fifty young and healthy male subjects between 19-24 yr of age got examined for autonomic reactivity. Twenty five of them were having family history of hypertension (study group) while the remaining were the children of normotensive parents (control group). Non invasive autonomic function tests as per Ewing's criteria were performed in all the subjects. The resting heart rate, systolic and diastolic blood pressures were not significantly raised in subjects of study group. The sympathetic function tests as assessed by rise in diastolic blood pressure following cold pressor test and hand grip test were highly significant in study group as compared with control one. However, the vagally mediated tests, for heart rate responses, denoting parasympathetic functions were similar in both groups. It seems that there is increased sympathetic activity in children of hypertensive parents without parasympathetic modulation in early life. It may predispose them to hypertension in their later life.