Abstract：
Long-distance \"thru-hiking\" has extraordinary physical demands and has become increasingly popular. This report describes a man (55 y) who thru-hiked the Pacific Crest Trail in 2021 and was at risk of developing the relative energy deficiency in sport (RED-S) syndrome. Hiking distance was 3767 km over 128 d. Eighty-eight days (69%) were full days of hiking, covering 38±8 km/d (mean±SD) in 7.9±1.6 h/d. Exercise energy expenditure above rest (heart rate vs indirect calorimetry regression method) was 2834±1518 kcal/d, total energy expenditure was 5702±1323 kcal/d, and energy intake was 4141 kcal/d. Body mass decreased by 9%, and fat mass (dual-energy X-ray absorptiometry) decreased by 46%. Energy availability (energy intake minus exercise energy expenditure) was 19.3 kcal/d/kg fat-free mass, indicating low energy availability (defined as <30 kcal/d/kg). Dual-energy X-ray absorptiometry-measured spine bone mineral density (BMD) decreased by 8.6%, with little to no decrease in total hip (-1.0%) and femoral neck (-1.5%) BMD. Total cholesterol, low-density lipoprotein cholesterol, and triglycerides increased by 24, 39, and 57%, respectively. Within 8 mo after the hike, BMD and serum lipids nearly or fully returned to baseline. No changes in high-density lipoprotein cholesterol, glycemia, or blood pressure were observed. According to guidelines, these observations are consistent with a moderate risk of RED-S, and a medical evaluation and treatment plan are advisable in order to avoid clinical manifestations (eg, stress fractures, anemia, psychological disturbances). To minimize RED-S risk, it may be prudent for thru-hikers to optimize energy availability by moderating daily hiking distances and/or increasing food intake.
摘要：
长途“穿越徒步旅行”具有非凡的身体需求，并且越来越受欢迎。这份报告描述了一名男子（55岁），他在2021年穿越了PacificCrestTrail，并有发展为运动中相对能量不足（RED-S）综合征的风险。超过128d的远足距离为3767公里。88天（69％）是全天远足，在7.9±1.6h/d中覆盖38±8km/d（平均值±SD）。运动能量消耗高于休息（心率与间接量热法回归法）为2834±1518kcal/d，总能量消耗为5702±1323千卡/天，能量摄入量为4141kcal/d。体重下降了9%,脂肪量（双能X射线吸收法）减少了46％。能量可用性（能量摄入减去运动能量消耗）为19.3kcal/d/kg无脂质量，表明能量可用性低（定义为<30kcal/d/kg）。双能X线骨密度仪测量脊柱骨密度（BMD）下降了8.6％，总髋关节（-1.0％）和股骨颈（-1.5％）BMD几乎没有下降。总胆固醇,低密度脂蛋白胆固醇，甘油三酯分别增加了24%、39%和57%，分别。徒步旅行后8个月内，BMD和血脂几乎或完全恢复到基线。高密度脂蛋白胆固醇没有变化，血糖，或观察血压。根据指导方针,这些观察结果与RED-S的中等风险是一致的，并且建议进行医学评估和治疗计划，以避免临床表现（例如，应力断裂,贫血,心理障碍)。为了最小化RED-S风险，通过减少每日徒步旅行距离和/或增加食物摄入量来优化能量供应可能是明智的。
