EPOC variables.

Fibroblast growth factor 21 (FGF21) is a metabolic regulator that may increase in circulation following exercise. This study was undertaken to determine if changes to FGF21 post-exercise are dependent on biological sex and exercise modality. Secondary analyses were conducted to determine if the post-exercise rise in FGF21 was associated with upstream signaling factors (glucagon, epinephrine, glucose) and excess post-exercise oxygen consumption (EPOC) response. Following a randomized crossover design, male and female participants completed two, thirty minute exercise protocols – during the steady state (SS) protocol, participants cycled at 70% of VO2peak and during the sprint interval exercise (IE) protocol participants completed six, thirty second “all out” sprints against 7.5% of body weight with four and half minutes of active recovery between sprints. Blood samples were taken at baseline, immediately post-exercise (IPE), and 1-hour post-exercise. Oxygen consumption was monitored continuously throughout the trials. In males, FGF21 levels were increased at 1-hour post-exercise with no difference between conditions; in females, FGF21 levels were unchanged as a result of exercise. Comparison of the post-exercise FGF21 incremental area under the curve revealed that in the SS condition males had a greater FGF21 response than females and that within males the SS condition had a greater response than the IE condition. Exercise significantly increased FGF21 levels in males, but not in females. In males, FGF21 levels were greater in the SS condition than in the IE condition.成纤维细胞生长因子21（Fibroblast growth factor 21, FGF21）是一种代谢调节因子，运动后其循环水平可能升高。本研究旨在探讨运动后FGF21的变化是否依赖于受试者的生物学性别与运动模式。后续分析用于明确运动后FGF21的升高是否与上游信号因子（胰高血糖素、肾上腺素、葡萄糖）及运动后过量氧耗（EPOC）反应相关。本研究采用随机交叉设计，招募男女受试者完成两项30分钟运动方案：稳态（SS）方案中，受试者以峰值摄氧量（VO2peak）的70%强度骑行；间歇冲刺运动（IE）方案中，受试者完成6次持续30秒的全力冲刺，每次冲刺需对抗相当于自身体重7.5%的阻力，且每次冲刺间隔设有4.5分钟的主动恢复期。研究分别在基线、运动后即刻（IPE）及运动后1小时采集血液样本，试验全程持续监测受试者的摄氧量。结果显示，男性受试者在运动后1小时的FGF21水平显著升高，且两种运动方案间无显著差异；而女性受试者的FGF21水平未因运动发生改变。对运动后FGF21的曲线下增量面积进行比较后发现，稳态方案下男性的FGF21应答水平显著高于女性，且在男性受试者中，稳态方案的应答水平高于间歇冲刺运动方案。运动可显著升高男性的FGF21水平，但对女性无此影响。在男性受试者中，稳态方案下的FGF21水平显著高于间歇冲刺运动方案。