Jörres Marc, Gunga Hanns-Christian, Steinach Mathias
Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Center for Space Medicine and Extreme Environments, Berlin, Germany.
Front Physiol. 2021 Mar 11;12:640710. doi: 10.3389/fphys.2021.640710. eCollection 2021.
Long-endurance exercises like ultramarathons are known to elicit various metabolic and physiological changes in the human body. However, little is known about very long-duration exercise at low intensities regarding healthy human subjects.
The purpose of this study was to evaluate changes in body composition and metabolism in long-endurance but low-intensity events.
Twenty-five male and 18 female healthy recreational athletes (age 34.6 ± 8.8 years; BMI: 22.4 ± 2.0 kg/m) of the "100 km Mammutmarsch" were recruited for participation during the events in 2014-2016. Other than classical ultramarathons, the "Mammutmarsch" is a hiking event, in which participants were required to walk but not run or jog. It was expected to complete the 100-km distance within 24 h, resulting in a calculated mean speed of 4.17 km/h, which fits to the mean speed observed (4.12 ± 0.76 km/h). As not all participants reached the finish line, comparison of finishers (FIN, = 11) and non-finishers (NON, = 21) allowed differential assessment of performance. Body composition measured through bioelectrical impedance analysis (BIA) was determined pre- and post-event, and serum samples were taken pre-event, at 30, 70, and 100 km to determine NT-pro-BNP, troponin T, C-reactive protein (CRP), cortisol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, total cholesterol, total creatine kinase (CK), CK-MB, aminotransferase (AST), ALT, and sodium levels. Nineteen participants wore actimeter armbands (SenseWear) to gain information about body activity and exercise intensity [metabolic equivalent of task (MET)]. Sixteen participants wore mobile heart rate monitors to assess mean heart rate during the race. Serum parameter alterations over the course of the race were analyzed with mixed-effects ANOVA and additional -tests. All serum parameters were analyzed for correlation concerning different MET levels, speed, age, BMI, baseline NT-pro-BNP, mean heart rate during the race, and sex with linear regression analysis.
We found significant elevations for muscle and cardiac stress markers (CRP, CK, CK-MB, AST, ALT, cortisol, and NT-pro-BNP) as well as decreasing markers of lipid metabolism (cholesterol, triglycerides, LDL). Although the intensity level demanded from our participants was low compared with other studies on (ultra-) marathons, the alteration of tested parameters was similar to those of high-intensity exercise, e.g., NT-pro-BNP showed a fourfold increase ( < 0.01) and LDL decreased by 20% ( = 0.05). Besides the duration of exercise, age, BMI, training status, and sex are relevant parameters that influence the elevation of stress factors. Notably, our data indicate that NT-pro-BNP might be a marker for cardiovascular fitness also in healthy adults.
This low-intensity long-endurance walk evoked a strong systemic reaction and large cell stress and shifted to a favorable lipid profile, comparable to higher intensity events. Despite increasing cardiac stress parameters, there were no indications of cardiac cell damage. Remarkably, the duration seems to have a greater influence on stress markers and metabolism than intensity.
像超级马拉松这样的长时间耐力运动已知会在人体中引发各种代谢和生理变化。然而，对于健康人体受试者进行的低强度超长时间运动，我们了解甚少。
本研究的目的是评估长时间耐力但低强度运动中身体成分和代谢的变化。
招募了25名男性和18名女性健康的业余运动员（年龄34.6±8.8岁；体重指数：22.4±2.0kg/m²）参加2014 - 2016年的“100公里猛犸象徒步活动”。除了传统的超级马拉松，“猛犸象徒步活动”是一项徒步赛事，要求参与者步行而非跑步或慢跑。预计要在24小时内完成100公里的路程，计算得出平均速度为4.17公里/小时，这与观察到的平均速度（4.12±0.76公里/小时）相符。由于并非所有参与者都到达了终点线，对完成者（FIN，n = 11）和未完成者（NON，n = 21）进行比较，从而对表现进行差异评估。通过生物电阻抗分析（BIA）测量身体成分，在活动前后进行测定，并在活动前、30公里、70公里和100公里时采集血清样本，以测定N末端B型利钠肽原（NT-pro-BNP）、肌钙蛋白T、C反应蛋白（CRP）、皮质醇、低密度脂蛋白（LDL）、高密度脂蛋白（HDL）、甘油三酯、总胆固醇、总肌酸激酶（CK）、肌酸激酶同工酶（CK-MB）、转氨酶（AST）、谷丙转氨酶（ALT）和钠水平。19名参与者佩戴了活动计步臂带（SenseWear）以获取身体活动和运动强度[任务代谢当量（MET）]的信息。16名参与者佩戴了移动心率监测器以评估比赛期间的平均心率。使用混合效应方差分析和额外的检验分析比赛过程中血清参数的变化。通过线性回归分析，分析所有血清参数与不同MET水平、速度、年龄、体重指数、基线NT-pro-BNP、比赛期间的平均心率和性别之间的相关性。
我们发现肌肉和心脏应激标志物（CRP、CK、CK-MB、AST、ALT、皮质醇和NT-pro-BNP）显著升高，以及脂质代谢标志物（胆固醇、甘油三酯、LDL）降低。尽管与其他关于（超级）马拉松的研究相比，我们的参与者所需的强度水平较低，但测试参数的变化与高强度运动相似，例如NT-pro-BNP增加了四倍（P < 0.01），LDL降低了20%（P = 0.05）。除了运动持续时间外，年龄、体重指数、训练状态和性别都是影响应激因素升高的相关参数。值得注意的是，我们的数据表明NT-pro-BNP在健康成年人中也可能是心血管健康的一个标志物。
这种低强度的长时间耐力步行引发了强烈的全身反应和较大的细胞应激，并转变为有利的脂质谱，与高强度运动相当。尽管心脏应激参数增加，但没有心脏细胞损伤的迹象。值得注意的是，持续时间似乎比强度对应激标志物和代谢的影响更大。
