The effect of duration of exercise at the ventilation threshold on subjective appetite and short-term food intake in 9 to 14 year old boys and girls

BACKGROUND The effect of exercise on subjective appetite and short-term food intake has received little investigation in children. Despite a lack of reported evaluation of short-duration activity programs, they are currently being implemented in schools as a means to benefit energy balance. The purpose of this study was to determine the effect of duration of exercise at the ventilation threshold (VeT) on subjective appetite and short-term food intake in normal weight boys and girls aged 9 to 14 years. METHODS On 4 separate mornings and in random order, boys (n = 14) and girls (n = 15) completed 2 rest or 2 exercise treatments for 15 (short-duration; SD) or 45 min (long-duration; LD) at their previously measured VeT, 2 h after a standardized breakfast. Subjective appetite was measured at regular intervals during the study sessions and food intake from a pizza meal was measured 30 min after rest or exercise. RESULTS An increase in average appetite, desire to eat, and hunger (p < 0.05) was attenuated by SD exercise, but was further increased (p < 0.05) by LD exercise. However, food intake after SD and LD exercise was similar to after rest in both boys and girls (p = 0.55). The energy cost of SD and LD exercise resulted in a lower net energy balance compared to resting during the study measurement period in boys (SD: Delta = -418 +/- 301 kJ; LD: Delta = -928 +/- 196 kJ) and in girls (SD: Delta = -297 +/- 105 kJ; LD: Delta = -432 +/- 115 kJ). CONCLUSION Neither SD nor LD exercise at the VeT increased short-term food intake and SD exercise attenuated increases in appetite. Thus, SD exercise programs in schools may be an effective strategy for maintaining healthier body weights in children.