Effect of moderate-intensity exercise bouts lasting <10 minutes on body composition in sedentary Kenyan adults aged ≥50 years

Abstract

Background Sedentary lifestyles and related morbidities are rising among adults despite existing exercise recommendations. Appealing exercise regimes yielding similar/better body composition should be sought. Objective We investigated the effect of moderate-intensity exercise bouts of <10 min on body composition in previously sedentary adults. Methods This unblinded study enrolled 53 healthy sedentary volunteers aged ≥50 years, randomised into one of two gender-balanced exercise interventions: (1) male and (2) female short-duration bouts (M S, n=14; F S, n = 13), and (3) male and (4) female long-duration bouts (M L, n=13; F L, n=13). Short-duration bouts entailed 5-10 min of jogging thrice daily; long-duration bouts, 30-60 min 3-5 days weekly. Body composition was determined at recruitment and 8-weekly thereafter, for 24 weeks. Results At baseline, 14.3% of M S, 38.5% of M L, 92.3% of F S and 69.2% of F L were obese, dropping to 7.1%, 15.4%, 61.5% and 30.8%, respectively. For waist:height ratio, 64.3 % of M S, 76.9% of M L, 100% of F S and 84.6.3% of F L had ratios >0.5, dropping to 42.9%, 30.8%, 92.9% and 26.2%, respectively. While baseline M S and M L waist:hip ratio (WHR) ≥0.9 were 64.3% and 69.2%, respectively, they correspondingly dropped to 23.1% and 21.4%. The F S and F L with WHR ≥0.85 dropped from 46.2% to 15.4% and from 30.8% to 7.7%, respectively. Body composition variables improved for both sexes (all p <0.05) and mean change between exercise regimes was comparable for both sexes. Conclusion In equal cumulative times, moderate-intensity exercise bouts lasting <10 min are comparable with current 30-60 min bouts in body composition modification for adults of ≥50 years.