Tiller Nicholas B, Chiesa Scott T, Roberts Justin D, Turner Louise A, Jones Siana, Romer Lee M
Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, United Kingdom.
Institute of Cardiovascular Science, University College London, London, United Kingdom.
Front Physiol. 2019 May 15;10:589. doi: 10.3389/fphys.2019.00589. eCollection 2019.
This case-report characterized the respiratory, cardiovascular, and nutritional/gastrointestinal (GI) responses of a trained individual to a novel ultra-endurance exercise challenge. A male athlete (age 45 years; Omax 54.0 mL⋅kg⋅min) summited 100 mountains on foot in 25 consecutive days (all elevations >600 m). Laboratory measures of pulmonary function (spirometry, whole-body plethysmography, and single-breath rebreathe), respiratory muscle function (maximum static mouth-pressures), and cardiovascular structure and function (echocardiography, electrocardiography, large vessel ultrasound, and flow-mediated dilatation) were made at baseline and 48 h post-challenge. Dietary intake (four-day food diary), self-reported GI symptoms and plasma endotoxin concentrations were assessed at baseline, pre/post mid-point, pre/post end-point, and 48 h post-challenge. The challenge was completed in a total exercise time of 142 h (5.3 ± 2.8 h⋅d), with a distance of 1141 km (42.3 ± 43.9 km⋅d), and energy expenditure of 80460 kcal (2980 ± 1451 kcal⋅d). Relative to baseline, there were post-challenge decreases in pulmonary capacities and expiratory flows (≤34%), maximum expiratory mouth-pressure (19%), and maximum voluntary ventilation (29%). Heart rate variability deteriorated, manifesting as a 48% decrease in the root mean square of successive differences and a 70% increase in the low-frequency/high-frequency ratio. Pre- to post-challenge endotoxin concentrations were elevated by 60%, with a maximum increase of 130% after a given stage, congruent with an increased frequency and severity of GI symptoms. The challenge resulted in pulmonary and autonomic dysfunction, endotoxaemia, and GI distress. The findings extend our understanding of the limits of physiological function and may inform medical best-practice for personnel supporting ultra-endurance events.
本病例报告描述了一名训练有素的个体在一项新型超耐力运动挑战中的呼吸、心血管和营养/胃肠道（GI）反应。一名男性运动员（45岁；最大摄氧量54.0 mL·kg·min）在连续25天内徒步攀登了100座山峰（所有海拔均>600米）。在基线和挑战后48小时进行了肺功能（肺活量测定、全身体积描记法和单次呼吸再呼吸）、呼吸肌功能（最大静态口腔压力）以及心血管结构和功能（超声心动图、心电图、大血管超声和血流介导的扩张）的实验室测量。在基线、中点前后、终点前后以及挑战后48小时评估饮食摄入量（四天饮食日记）、自我报告的胃肠道症状和血浆内毒素浓度。挑战在总运动时间142小时（5.3±2.8小时/天）内完成，距离为1141公里（42.3±43.9公里/天），能量消耗为80460千卡（2980±1451千卡/天）。相对于基线，挑战后肺容量和呼气流量降低（≤34%），最大呼气口腔压力降低（19%），最大自主通气量降低（29%）。心率变异性恶化，表现为连续差值的均方根降低48%，低频/高频比值增加70%。挑战前后内毒素浓度升高了60%，在特定阶段后最大增加130%，这与胃肠道症状的频率和严重程度增加相一致。该挑战导致了肺和自主神经功能障碍、内毒素血症和胃肠道不适。这些发现扩展了我们对生理功能极限的理解，并可能为支持超耐力赛事的人员提供医学最佳实践参考。
