Effects of long versus short bout exercise on fitness and weight loss in overweight females.

Objective: The specific aim of this study was to determine if three 10 minute bouts of exercise per day (3 x 10) and two 15 minute bouts per day (2 x 15) were as effective as one 30 minute bout per day (1 x 30) for improving VO2 max and weight loss.

Methods: Overweight, female college students (body mass index > or = 28 kg/m2) were recruited and assessed at baseline and post-treatment for aerobic fitness (Astrand maximal cycle test), weight, skinfold thickness (7-site), and circumference measures (4-site). Following measurement of resting energy expenditure (REE), subjects were asked to follow a self-monitored calorie restricted diet (80% of REE) for the twelve week duration of the study and were assigned (non-random) to one of four treatment groups: 1) a nonexercising control group (control, n = 8), 2) a 30 minutes continuous exercise group (1 x 30, n = 12), 3) a 30 minutes accumulated exercise group (2 x 15, n = 10) and 4) a second 30 minutes accumulated exercise group (3 x 10, n = 8). The exercising subjects participated in aerobic exercise training at 75% of heart rate reserve three to five days per week with all exercise monitored.

Results: VO2 max increased significantly while weight, body mass index, sum of skinfolds, and sum of circumferences decreased significantly from baseline to post-treatment in the 1 x 30, 2 x 15 and the 3 x 10 groups, but not in the control group. A tertiary finding was that exercise participation did not differ among the exercising groups with regard to the average number of days per week.

Conclusions: These results support the hypothesis that exercise accumulated in several short bouts has similar effects as one continuous bout with regard to aerobic fitness and weight loss during caloric restriction in overweight, young women.