Postexercise decrease in arterial blood pressure, total peripheral resistance and in circulatory responses to brief hyperoxia in subjects with mild essential hypertension

The objective of our study was: (1) to compare the influence of moderate ex ercise on circulatory after-response in mildly hypertensive (n=8) and normo tensive male subjects (n = 9); (2) to examine the circulatory response to 3 -min hyperoxic inactivation of arterial chemoreceptors at rest and during p ostexercise period in both groups. Hypertensive men (HTS) with a systolic b lood pressure (SBP) 148 +/- 5 mm Hg, diastolic blood pressure (DBP) 92.4 +/ - 4 mm Hg; and normotensive men (NTS), with a SEP 126 +/- 3 mm Hg, DBP 75.6 +/- 1.3 mm Hg, were submitted to 20-min of moderate exercise on a cycloerg ometer (up to the level of 55% of each subject's resting heart rate reserve ), Finger arterial BP was recorded continuously with Finapres, impedance re ography was used for recording stroke volume, cardiac output and arm blood flow, In HTS a significant decrease in SEP by 14.5 +/- 3.4 mm Hg, DBP by 8. 9 +/- 1.9 mm Hg, total peripheral resistance (TPR) by 0.45 +/- 0.05 TPR u, (33.7 +/- 2.7%), and in arm vascular resistance (AVR) by 11.0 +/- 2.7 PRU u , (35.6 +/- 7%), was observed over a 60-min postexercise period, NTS exhibited insignificant changes in SEP, DBP, AVR except a significant d ecrease in TPR limited only to 20-min postexercise period. Hyperoxia decrea sed SEP, DBP and TPR in HTS, This effect was significantly attenuated durin g the postexercise period, Long-lasting antihypertensive effect of a single dynamic exercise in HTS suggests that moderate exercise may be applied as an effective physiological procedure to reduce elevated arterial BP in mild hypertension. We suggest also that the attenuation of the sympathoexcitato ry arterial chemoreceptor reflex may contribute to a postexercise decrease in arterial BP and in TPR in mildly hypertensive subjects.