Although physical activity (PA) is an essential factor in the prevention and management of type 2 diabetes, individuals with type 2 diabetes still remain inactive. In 2007, the updated PA recommendations included the accumulation of several short bouts (10 min or more) of moderate- intensity physical activity (PAaccum). Despite the updated recommendation, limited scientific evidence exists on its effectiveness of PAaccum on health outcomes including high blood pressure (BP). Purpose: To examine the effects of the PAaccum vs. a single continuous session (PAcont) on BP reduction in men with hypertension and prehypertension. Methods: Twenty three men (35.9±9.4 yrs; 137.8±9.3 /88.4±7.8 mm Hg)) with hypertension and prehypertension participated in a randomized cross-over design. Men completed three treatments: a control and two PA sessions, the PAaccum (four 10-min walk 50-min apart at 50% of VO2peak) and the PAcont (40-min walk at 50% of VO2peak). Two PA sessions were separated by ＞7 days. After each treatment, participants wore an ambulatory BP monitor beginning at the same time of day for 24 hrs. Systolic (S) and diastolic (D) BP were averaged for 24 hrs, daytime (06:00-22:00 hr) and nighttime (22:00-06:00 hr). One-way ANOVAs with repeated measures were used to determine the effects of each PA treatment on the BP reduction (p ＜0.05). Results: Main effects were found in 24-hr (p＜0.0001), daytime (p=0.001) and nighttime SBP (p=0.032) and 24-hr (p=0.021) and daytime DBP (p=0.023) while none were found in nighttime DBP (p=0.082). The 24-hr SBP was decreased 3.0 mmHg following the PAaccum and 4.7 mm Hg following the PAcont, respectively. The 24-hr DBP was decreased 2.3 mmHg following the PAaccum and 2.3 mm Hg following the PAcont, respectively. Daytime SBP was decreased 2.9 mmHg following the PAaccum and 4.5 mm Hg following the PAcont. Daytime DBP was decreased 2.3 mmHg following the PAaccum and 2.3 mm Hg following the PAcont, respectively. Nighttime SBP was 4.5 mm Hg following the PAcont. In addition, SBP was significantly reduced following the 2^nd (-6.5 mm Hg), and the 3^rd (-6.1 mm Hg) short sessions compared to the baseline (142.6±11.1 mm Hg) in hypertension. Conclusion: The accumulation of physical activity reduced BP for 24 hrs in men with hypertension and prehypertension. The PAaccum was as effective as the PAcont in reducing 24-hr and daytime SBP and DBP. Accumulating 10-min brisk walks appears to be effective for the treatment and prevention of hypertension.