Background: This study investigated health-related effects of exercise programs with exercise sessions of similar intensity but different frequency and duration.
Methods: Thirty-four overweight women were randomized into either long-bout (LB) or short-bout (SB) exercise groups. Participants performed an 8-week supervised program, with the LB group exercising for 75 minutes twice per week, and the SB group for 30 minutes on 5 days of the week.
Results: The LB group completed 16 sessions at a heart rate (HR) of 127 ± 1 beat·min-1 and the SB group completed 40 sessions at a HR of 126 ± 1 beat·min-1. Weekly energy expenditure of exercise was not different between groups (LB group, 5.64 ± 0.34 MJ; SB group, 5.83 ± 0.23 MJ). Training significantly (P < .05) increased measures of cardiorespiratory fitness, decreased waist circumference, insulin resistance, and diastolic blood pressure. The group × time interaction was not significant for any of these factors, indicating that responses to exercise training did not differ between the SB and LB groups.
Conclusions: Health-related outcomes of exercise programs with similar energy expenditure are independent of frequency and duration of exercise sessions. This provides individuals with a degree of flexibility in exercise program planning.