Effect of fixed 7.5 minutes’ moderate intensity exercise bouts on body composition and blood pressure among sedentary adults with prehypertension in Western-Kenya
Authors: Magutah Karani , Mbuthia Grace , Akiruga James Amisi , Haile Diresibachew , Thairu Kihumbu 
Published: July 2022

Prehypertension is a modifiable risk factor for cardiovascular disease observed to affect an estimated 25–59% of global population and closely associated with body composition. Without appropriate interventions, one-third of individuals with prehypertension would develop full-blown hypertension within 4 years. The existing exercise recommendations need substitutes that appeal more yet accord similar or better outcomes in desire to halt this progression. This study evaluated the effect of Fixed 7.5-minute Moderate Intensity Exercise (F-7.5m-MIE) bouts on Body Composition and Blood Pressure (BP) among sedentary adults with prehypertension in Western-Kenya in a Randomized Control Trial (RCT) performed throughout the day compared to the single-continuous 30-60-minute bouts performed 3 to 5 times weekly. This RCT, with three arms of Experimental Group1 (EG1) performing the F-7.5m-MIE bouts, Experimental Group 2 (EG2) performing current World Health Organization (WHO) recommendation of ≥30-min bouts, and, control group (CG), was conducted among 665 consenting pre-hypertensive sedentary adults enrolled from western Kenya. EG1 and EG2 performed similar weekly cumulative minutes of moderate intensity exercises. Adherence was determined using activity monitors and exercise logs. Data regarding demographic characteristics, heart rate, BP, and anthropometric measures were collected at baseline and 12thweek follow-up. Data regarding univariate, bivariate and multivariate (repeated measurements between and within groups) analysis were conducted using STATA version 13 at 5% level of significance. The study revealed that males (92.1% in EG1, 92% in EG2 and 96.3% in CG) and females (94.6% in EG1, 89.3% in EG2 and 95% in CG) in the three arms completed the exercise at follow-up respectively. At 12thweek follow-up from all exercise groups, males’ and females’ measurements for waist-hip-ratio, waist-height-ratio, systolic BP (SBP), heart rate and pulse pressure showed significant drops from baseline, while diastolic BP (DBP) and body mass index (BMI) reported mixed results for males and females from the various treatments. Both treatments demonstrated favourable outcomes. However, differences in the change between baseline and endpoint yielded mixed outcomes (SBP; p<0.05 for both males and females, DBP; p<0.05 for males and females, waist-height-ratio; p = 0.01 and <0.05 for males and females respectively, waist-hip-ratio; P = 0.01 and >0.05 for males and females respectively, BMI; p>0.05 for both males and females, heart rate; p<0.05 for males and females and pulse pressure; p = 0.01 and >0.05 for males and females respectively). The study design however could not test for superiority. The study demonstrated that the F-7.5m- MIE treatment programme and the WHO recommended 3–5 times weekly bouts of 30–60 minutes regime produced comparably similar favourable outcomes in adherence and BP reductions with improved body composition.

Trial registration: Trial registered with Pan African Clinical Trial Registry (www.pactr.org): no. PACTR202107584701552. (S3 Text)