Title

The influence of exercise intensity on postexercise hypotension among middle-aged men with high normal to Stage I hypertension

Date of Completion

January 2002

Keywords

Health Sciences, Public Health|Health Sciences, Recreation

Degree

Ph.D.

Abstract

This study investigated the influence of exercise intensity on the magnitude and duration of postexercise hypotension (PEH) in the laboratory and under ambulatory conditions in men with high blood pressure (BP). Subjects were 22 men (47.8 ± 0.9 yr.) with high normal to Stage I hypertension (139.7 ± 1.6/86.2 ± 1.2 mm Hg). Participants completed 30-min of cycling at 40% and 60% maximal oxygen consumption (VO2max) and quiet sitting in random order on three separate days. Following each condition, BP was measured for 1 hr in the laboratory and by ambulatory BP monitor until the next morning. RMANOVA compared the BP response between experimental conditions. In the laboratory, average systolic BP (SBP) was lower than baseline following 40% and 60% VO 2max, 4.7 ± 1.3 mm Hg from 128.9 ± 1.6 mm Hg and 7.1 ± 1.3 mm Hg from 129.2 ± 2.1 mm Hg (p = 0.001), respectively. Mean DBP was also reduced for 1 h after 40% and 60% VO2max, 1.7 ± 0.7 mm Hg from 86.9 ± 1.0 mm Hg and 2.0 ± 0.6 mm Hg from 87.5 ± 1.0 mm Hg (p = 0.02), respectively. SBP and DBP were unchanged by rest. The postexercise BP response in the laboratory was not influenced by exercise intensity. Upon leaving the laboratory, average daytime ambulatory SBP was higher than baseline after exercise and rest. However, the increase in SBP was less after 40% (3.0 ± 1.7 mm Hg) and 60% (0.9 ±1.6 mm Hg) VO2max than rest (6.8 ± 1.4 mm Hg) (p = 0.01). Mean daytime ambulatory DBP continued to decrease upon exiting the laboratory for 40% (1.1 ± 0.9 mm Hg) and 60% (1.4 ± 0.9 mm Hg) VO2max, but increased after rest (1.0 ± 0.9 mm Hg) (p = 0.03). The postexercise BP response under ambulatory conditions was not influenced by exercise intensity. In conclusion, PEH is greater in the laboratory than under ambulatory conditions and was not influenced by exercise intensity. Nonetheless, daytime ambulatory BP was lower following moderate intensity aerobic exercise, providing men with hypertension the benefit of having lower BP throughout the day. ^