150 minutes weekly accumulated exercise as an efficient alternative to continuous exercise: evidence from a randomized trial in young women

Abstract Background Physical inactivity is a prevalent issue, particularly among women. While accumulated exercise (AE) is a promising intervention strategy, it remains unclear whether it can achieve similar health benefits to the WHO-recommended 150 min of physical activity per week. Objective This study compares the effects of the WHO-recommended aerobic exercise dose (150 min/week) as AE versus moderate-intensity continuous exercise (MICE) on body composition, metabolic syndrome risk, atherosclerosis, aerobic capacity, and muscle strength in sedentary young women. Methods Sixty young women were randomized into two groups: the AE group ( n = 30) and the MICE group ( n = 30). Both groups performed 150 min of weekly exercise: AE consisted of three short daily sessions, while MICE involved three longer sessions per week. The intervention lasted for 8 weeks, with body composition, muscle strength, metabolic syndrome risk, atherosclerosis, and aerobic capacity measured before and after the intervention. A two-way repeated measures ANOVA (time × group) was used to analyze training effects, with Bonferroni post hoc tests. Effect sizes were reported as partial eta squared ( $$\:{\varvec{\upeta\:}}_{\mathbf{p}}^{2}$$ ) or Cohen’s d, with significance set at p < 0.05. Results Both AE and MICE groups showed significant pre-to-post changes in body weight ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.46), BMI ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.45), body fat percentage ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.70), waist-to-hip ratio ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.54), kneeling push-ups ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.85), long-standing jumps ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.80), sit-ups ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.31), body-weight squats ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.85), V̇O₂ max ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.54), TG ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.35), HDL ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.28), TC ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.10), and atherogenic index ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.52) (all p < 0.05). No significant pre-to-post changes were found for SBP ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.01), DBP ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.01), LDL ( $$\:{{\upeta\:}}_{\text{p}}^{2}$$ =0.001) (all p >0.05). These pre-to-post changes were not significantly different between the AE and MICE groups for any outcome (all p >0.05). The adherence rates were 94.9% in AE and 90.7% in MICE. Conclusion AE and MICE showed similar modest pre-post changes, with no significant between-group differences. These findings should be interpreted cautiously, given the small sample size and absence of a control group. Further large-scale randomized controlled trials are warranted before AE can be recommended as an alternative exercise strategy.