Influence of age and gender on cold pressor response in Indian population.

Cold pressor test (CPT) is a simple and well documented laboratory test to evaluate the propensity for hypertension and sympathetic autonomic functions. Role of sex hormones was tested in the present study for the cold pressor response (CPR) in young adults of both sexes and in elderly population. The subjects comprised of young male (n=55), female (n=32) medical students of 17-25 years and elderly males (n=39) and females (n=25) of 50-70 years of age. The CPT was carried out in young and elderly males and females with one minute immersion of one hand in ice cold water (0-4 degrees C). Both in young males and females the absolute rise in SBP and DBP in response to Cold pressor test (CPT) was highly significant, with diastolic percent rise exceeding systolic. In comparison to young males, the females showed greater percent rise in SBP and DBP. Similarly, in elderly groups of both sexes, CPR was associated with significant absolute rise in SBP and DBP with diastolic percent rise more than systolic in males only. Both in young versus elderly males and young versus elderly females comparison yielded comparable percent rise in SBP and DBP. The SBP and DBP percent rise was again comparable between elderly males and females. The greater responsiveness to CPT in young females could be attributed to increased pain sensitivity to cold, and/or genetic and hereditary factors overwhelming the hormonal protection offered by estrogen and nitric oxide (NO).