Determinants of resting lipid oxidation in response to a prior bout of endurance exercise

A single bout of exercise can alter subsequent resting metabolism for many hours and into the next day. However, differences between men and women, effects of nutritional state, and relative effects of resting metabolic rate (RMR) and respiratory exchange ratio (RER) in controlling the increase in lipid oxidation (Lox) after exercise are not yet clear. Effects of aerobic capacity (VO2 peak) and exercise bout parameters (intensity and volume) also remain to be clearly elucidated as does the time course of changes after exercise. We performed a meta-analysis to assess these potential moderators of the impact of endurance exercise [effect sizes (ESs)] on subsequent Lox at rest (ES = 0.91; 95% CI: 0.69-1.12), on the day of exercise (ES = 1.22; 95% CI: 0.89-1.55), and on the following day (ES = 0.60; 95% CI: 0.35-0.85). ES for the exercise-related increase in resting Lox was significantly greater in men than women in the postabsorptive state but similar in the postprandial state. The ES for depression of RER after exercise was similar between men and women, while the ES for RMR in the postabsorptive state tended to be higher in men than women. Finally, VO2 peak and exercise energy expenditure (EEE), but not intensity, were predictive of postexercise Lox. The findings indicate importance of EEE and fitness for ability to achieve robust enhancement of Lox after exercise. The results additionally indicate a gender difference in postexercise Lox that is dependent on nutritional state, as the ES for Lox was lower in women only in the postabsorptive state.