Background

Ultra-trail running races pose appreciable physiological challenges, particularly for glucose metabolism. Previous studies that yielded divergent results only measured glycaemia at isolated times.

Objectives

We aimed to explore the impact of an ultra-endurance race on continuously measured glycaemia and to understand potential physiological mechanisms, as well as the consequences for performance and behavioural alertness.

Methods

Fifty-five athletes (78% men, 43.7 ± 9.6 years) ran a 156-km ultra-trail race (six 26-km laps, total elevation 6000 m). Participants wore a masked continuous glucose monitoring sensor from the day before the race until 10 days post-race. Blood was taken at rest, during refuelling stops after each lap, and after 24-h recovery. Running intensity (% heart rate reserve), performance (lap times), psychological stress, and behavioural alertness were explored. Linear mixed models and logistic regressions were carried out.

Results

No higher risk of hypo- or hyperglycaemia was observed during the exercise phases of the race (i.e. excluding stops for scientific measurements and refuelling) compared with resting values. Laps comprising a greater proportion of time spent at maximal aerobic intensity were nevertheless associated with more time > 180 mg/dL (P = 0.021). A major risk of hyperglycaemia appeared during the 48-h post-race period compared with pre-race (P < 0.05), with 31.9% of the participants spending time with values > 180 mg/dL during recovery versus 5.5% during resting. Changes in circulating insulin, cortisol, and free fatty acids followed profiles comparable with those usually observed during traditional aerobic exercise. However, creatine phosphokinase, and to a lesser extent lactate dehydrogenase, increased exponentially during the race (P < 0.001) and remained high at 24-h post-race (P < 0.001; respectively 43.6 and 1.8 times higher vs. resting). Glycaemic metrics did not influence physical performance or behavioural alertness.

Conclusion

Ultra-endurance athletes were exposed to hyperglycaemia during the 48-h post-race period, possibly linked to muscle damage and inflammation. Strategies to mitigate muscle damage or subsequent inflammation before or after ultra-trail races could limit recovery hyperglycaemia and hence its related adverse health consequences.

Trial Registration Number

NCT05538442 2022–09-21 retrospectively registered.

Graphical abstract

中文翻译：

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156 公里超越野赛对运动员血糖的影响：实地观察研究

背景

超越野跑比赛带来了相当大的生理挑战，尤其是葡萄糖代谢。先前产生不同结果的研究仅在孤立的时间测量血糖。

目标

我们的目的是探索超耐力比赛对连续测量的血糖的影响，并了解潜在的生理机制，以及对表现和行为警觉性的影响。

方法

55 名运动员（78% 为男性，43.7 ± 9.6 岁）进行了 156 公里的超越野赛（6 圈 26 公里，总海拔 6000 米）。参与者从比赛前一天到赛后 10 天都佩戴蒙面连续血糖监测传感器。在休息时、每圈后加油时以及 24 小时恢复后采血。探讨了跑步强度（心率储备百分比）、表现（单圈时间）、心理压力和行为警觉性。进行了线性混合模型和逻辑回归。

结果

与静息值相比，在比赛的运动阶段（即不包括停止进行科学测量和加油）没有观察到低血糖或高血糖的风险更高。然而，在最大有氧强度下花费的时间比例较大的圈数与 > 180 mg/dL 的时间较长相关（P  = 0.021）。与赛前相比，高血糖的主要风险出现在赛后 48 小时内（P  < 0.05），31.9% 的参与者在恢复期间血糖值 > 180 mg/dL，而在休息期间这一比例为 5.5%。循环胰岛素、皮质醇和游离脂肪酸的变化与传统有氧运动中通常观察到的变化相当。然而，肌酸磷酸激酶和较小程度的乳酸脱氢酶在比赛期间呈指数增加（P  < 0.001），并在赛后 24 小时保持较高水平（P  < 0.001；分别比休息时高 43.6 倍和 1.8 倍）。血糖指标不影响身体表现或行为警觉性。

结论

超耐力运动员在赛后 48 小时内会出现高血糖，这可能与肌肉损伤和炎症有关。在超越野比赛之前或之后减轻肌肉损伤或随后的炎症的策略可能会限制高血糖的恢复，从而限制其相关的不良健康后果。

试用注册号

NCT05538442 2022-09-21 追溯注册。

图形概要