The Duration of a Light Intensity Exercise Bout Affects Postexercise Hypotension

Abstract

0692 PURPOSE: The duration of exercise needed to elicit postexercise hypotension is not known. Therefore, we investigated the influence of short and longer bouts of light intensity endurance exercise on postexercise hypotension. METHODS: Subjects were 22 men (Mean ± SEM, 43.4 ± 9.9 y) with high normal to Stage 1 hypertension (143.8 ± 10.3/85.0 ± 8.5 mmHg) that were not taking medication for hypertension. Men randomly completed three experiments: a control session and two cycle exercise bouts at 40% maximal oxygen consumption, one for 15 min (short) and the other for 30 min (long). Experiments began with a 20 min baseline period and were conducted at the same time of day while separated by ≥ 2 d. An ambulatory BP monitor was worn after the experiments until the next morning. RMANOVA tested if BP differed over time and between experimental conditions. RESULTS: For 5 hr, the average increase in SBP from baseline was less after short (3.8 ± 1.9 mmHg) and long (3.5 ± 1.9 mmHg) duration exercise compared to control (10.3 ± 1.3) (P <0.05); and DBP decreased more after short (−1.7 ± 1.5 mmHg) (p = 0.081) and long (− 3.0 ± 0.7 mmHg) (p = 0.003) duration exercise than control (−0.7 ± 0.9 mmHg). For 14 hr, the average increase in SBP was less after long (1.6 ± 1.8 mmHg) than short (6.0 ± 2.6 mmHg) duration exercise and control (8.1 ± 1.8 mmHg) (P <0.01); and DBP decreased more after long (−7.3 ± 1.1 mmHg) than short (−3.3 ± 2.3 mmHg) duration exercise and control (−1.7 ± 1.5 mmHg) (P <0.001). CONCLUSIONS: For 5 hr, a light intensity dynamic exercise bout conducted for 15 or 30 min lowered BP compared to control conditions. However, over the remainder of the day, only the BP lowering effects of long but not short duration exercise was sustained among men with hypertension. Supported by an American Heart Association Grant-in-Aid # 0150507N