Energy compensation after sprint- and high-intensity interval training

BACKGROUND: Many individuals lose less weight than expected in response to exercise interventions when considering the increased energy expenditure of exercise (ExEE). This is due to energy compensation in response to ExEE, which may include increases in energy intake (EI) and decreases in non-exercise physical activity (NEPA). We examined the degree of energy compensation in healthy young men and women in response to interval training. METHODS: Data were examined from a prior study in which 24 participants (mean age, BMI, & VO(2)max = 28 yrs, 27.7 kg•m(-2), and 32 mL∙kg(-1)∙min(-1)) completed either 4 weeks of sprint-interval training or high-intensity interval training. Energy compensation was calculated from changes in body composition (air displacement plethysmography) and exercise energy expenditure was calculated from mean heart rate based on the heart rate-VO(2) relationship. Differences between high (≥ 100%) and low (< 100%) levels of energy compensation were assessed. Linear regressions were utilized to determine associations between energy compensation and ΔVO(2)max, ΔEI, ΔNEPA, and Δresting metabolic rate. RESULTS: Very large individual differences in energy compensation were noted. In comparison to individuals with low levels of compensation, individuals with high levels of energy compensation gained fat mass, lost fat-free mass, and had lower change scores for VO(2)max and NEPA. Linear regression results indicated that lower levels of energy compensation were associated with increases in ΔVO(2)max (p < 0.001) and ΔNEPA (p < 0.001). CONCLUSIONS: Considerable variation exists in response to short-term, low dose interval training. In agreement with prior work, increases in ΔVO(2)max and ΔNEPA were associated with lower energy compensation. Future studies should focus on identifying if a dose-response relationship for energy compensation exists in response to interval training, and what underlying mechanisms and participant traits contribute to the large variation between individuals.