Autonomic reflexes in borderline hypertensives.

Autonomic reflexes were studied in 53 patients with borderline hypertension (BLH) and 25 normotensives. BLH patients had higher basal heart rate. With 2 minutes of sustained head-up passive tilt of 50 degrees or 75 degrees, the rise in heart rate was comparable in both groups but the rise in blood pressure was significantly more in the BLH group. The rise in systolic pressure with Valsalva manoeuvre as well as with sustained hand grip was significantly higher in BLH patients. The postural tachycardia index and Valsalva index were significantly lower in BLH patients probably due to higher basal heart rate.