Effects of Fractionized and Continuous Exercise on 24-h Ambulatory Blood Pressure

BHAMMAR, D. M., S. S. ANGADI, and G. A. GAESSER. Effects of Fractionized and Continuous Exercise on 24-h Ambulatory Blood Pressure. Med. Sci. Sports Exerc., Vol. 44, No. 12, pp. 2270-2276, 2012. Purpose: The objective of this study is to compare the effects of fractionized aerobic exercise (three 10-min exercise sessions) and continuous exercise (one 30-min exercise session) on 24-h ambulatory blood pressure (ABP). Methods: Eleven healthy prehypertensive subjects (28.3 +/- 8.0 (SD) yr) completed three randomly assigned conditions: 1) three 10-min sessions of aerobic exercise (3 +/- 10 min), 2) one continuous 30-min session of aerobic exercise (1 x 30 min), and 3) a nonexercise control trial (control). The mode of exercise was walking on a motor-driven treadmill at 75%-79% of maximum heart rate (HRmax) (60%-65% (V) over dotO(2peak)). Twenty-four-hour ABP was monitored with an automated ABP device (Oscar 2 (TM); SunTech Medical, Morrisville, NC). Linear mixed models were used to compare 24-h ABP responses between trials. Results: The mean +/- SD 24-h systolic blood pressure (SBP) was significantly lower during the 3 +/- 10-min trial (127 +/- 15 mm Hg) compared with control (130 +/- 15 mm Hg) (P < 0.001). Although both 3 x 10-min and 1 x 30-min trials reduced SBP compared with control during daytime/evening (1300-2300 h), only the 3 x 10-min trial reduced SBP during nighttime (2300-0800 h, 118 +/- 16 vs 122 +/- 14 mm Hg, P = 0.024) and the following morning (0800-1200 h, 127 +/- 15 vs 131 +/- 15 mm Hg, P = 0.016). For 24 h, 26.7% of SBP values during 3 x 10 min were normal (i.e., <120 mm Hg) compared with 18.3% for 1 x 30 min and 19.4% for control (P < 0.001). Conclusions: In prehypertensive individuals, fractionized exercise (e.g., three 10-min aerobic exercise sessions spread and effective exercise alternative to continuous exercise for cardiovascular risk reduction in this population.