Author(s): Sheila R Pai1, Amrutha Mary2, Rekha D Kini1*and BhagyalakshmiK.1
Heart rate variability (HRV) is a topic of great interest because of its medical implications. Decreased HRV is associated with numerous conditions and has been used in risk stratifications for certain diseases. This study examines the effect of cold pressure stress on blood pressure and heart rate variability in the wards of hypertensive parents. The study included 67 subjects,30 with parental history of hypertension and 37 with had normotensive parents. Subjects were divided into two groups; Control group (wards of normotensive parents) and Study group (wards of hypertensive parents). Theheight, weight and body Mass Index were noted. Cold pressor test was done. Blood pressure (BP) was measured and electro cardio gram (ECG) was recorded during normal breathing, deep breathing and cold pressor test. HRV analysis was done by time domain method. The data obtained was analyzed using student’s t-test and by Mann-Whitney U-test and P < 0.05 was considered significant. Cold pressure stress showed a significant increase in systolic Blood Pressure and Diastolic Blood Pressure(DBP) in study group with respect to control group(p<0.01 ). In the time domain analysis, mean value of RMSSD of study group was lower (p<0.05) than control group after the cold pressor test. The study thus concluded that wards of hypertensive parents showed an increase in the blood pressure and decrease in HRV to cold pressor test. Hence the result of current study represents the reducedparasympathetic activity that is present in the group with parental history of hypertension during cold pressor test.