Attenuation of heart rate recovery after exercise in hypertensive patients with blunting of the nighttime blood pressure fall

Abstract

Objectives To evaluate whether hypertensive patients with attenuation of nighttime blood pressure (BP) fall exhibit a delay of the recovery of heart rate (HR) after exercise as an index of a general decrease in the vagal tone. Methods Mild-moderate hypertensive patients ( n = 219, age 55 ± 3, 77% men) underwent a maximal exercise test (Bruce > 85% heart rate limited) in whom we calculated the recovery of HR as the percent decrease of HR from peak to 1 min after stopping exercise (%HR fall − 1 min), a 24-h ambulatory BP monitoring, calculating the percent decrease of nighttime vs. daytime BP (% night SBP fall). Left ventricular mass index (LVMI) was measured by echo and aortic stiffness by pulse wave velocity (PWV). Sixty percent were on antihypertensive drugs (not on beta-blockers nor on non-dihydropiridine calcium blockers); 12 subjects were type 2 diabetics. Results: The “% night SBP fall” ranged from − 6.3% to 38.9% and the “%HR fall − 1 min” ranged from 3.3% to 43.7%. There was a significant positive correlation between these two variables ( r = 0.594, p < 0.001). Population was divided into five groups according to quintiles of values for the “% night SBP fall”. For similar daytime BP and age, the lowest quintile for % night SBP fall (− 6.3% to 7.2%) showed the lower “%HR fall − 1 min” (3.1 ± 0.5%), and the higher LVMI (92 ± 3 g/m 2) and PWV (12.1 ± 0.4 m/s) values comparing to the other quintiles ( p<0.02). Conclusions In hypertensives, blunting of the nocturnal fall of BP is associated with a delayed recovery in heart rate after graded maximal exercise and with greater aortic stiffness and ventricular mass. This may indicate that in non-dipper subjects a relative general decrease of parasympathetic reactivation after exercise is linked to the failure of nighttime fall of BP, both of which might contribute to target-organs deterioration.