Haddad Toni, Mons Valentin, Meste Olivier, Dempsey Jerome A, Abbiss Chris R, Brisswalter Jeanick, Blain Gregory M
LAMHESS, Sciences et Techniques des Activités Physiques et Sportives, Université Côte d'Azur, 261 Bd du Mercantour, 06200, Nice, France.
Centre VADER, Université Côte d'Azur, Nice, France.
Eur J Appl Physiol. 2024 Feb;124(2):651-665. doi: 10.1007/s00421-023-05346-6. Epub 2023 Nov 17.
We tested the hypothesis that breathing heliox, to attenuate the mechanical constraints accompanying the decline in pulmonary function with aging, improves exercise performance.
Fourteen endurance-trained older men (67.9 ± 5.9 year, [Formula: see text]O: 50.8 ± 5.8 ml/kg/min; 151% predicted) completed two cycling 5-km time trials while breathing room air (i.e., 21% O-79% N) or heliox (i.e., 21% O-79% He). Maximal flow-volume curves (MFVC) were determined pre-exercise to characterize expiratory flow limitation (EFL, % tidal volume intersecting the MFVC). Respiratory muscle force development was indirectly determined as the product of the time integral of inspiratory and expiratory mouth pressure (∫P) and breathing frequency. Maximal inspiratory and expiratory pressure maneuvers were performed pre-exercise and post-exercise to estimate respiratory muscle fatigue.
Exercise performance time improved (527.6 ± 38 vs. 531.3 ± 36.9 s; P = 0.017), and respiratory muscle force development decreased during inspiration (- 22.8 ± 11.6%, P < 0.001) and expiration (- 10.8 ± 11.4%, P = 0.003) with heliox compared with room air. EFL tended to be lower with heliox (22 ± 23 vs. 30 ± 23% tidal volume; P = 0.054). Minute ventilation normalized to CO production ([Formula: see text]/[Formula: see text]CO) increased with heliox (28.6 ± 2.7 vs. 25.1 ± 1.8; P < 0.001). A reduction in MIP and MEP was observed post-exercise vs. pre-exercise but was not different between conditions.
Breathing heliox has a limited effect on performance during a 5-km time trial in master athletes despite a reduction in respiratory muscle force development.
我们检验了这样一个假设，即呼吸氦氧混合气以减轻随着年龄增长肺功能下降所伴随的机械限制，可改善运动表现。
14名经过耐力训练的老年男性（67.9±5.9岁，[公式：见正文]O：50.8±5.8毫升/千克/分钟；预测值的151%）在呼吸室内空气（即21%O₂ - 79%N₂）或氦氧混合气（即21%O₂ - 79%He）的情况下完成了两次5公里自行车计时赛。在运动前测定最大流量 - 容积曲线（MFVC）以表征呼气流量受限（EFL，与MFVC相交的潮气量百分比）。呼吸肌力发展通过吸气和呼气口压力的时间积分（∫P）与呼吸频率的乘积间接测定。在运动前和运动后进行最大吸气和呼气压力动作以评估呼吸肌疲劳。
与呼吸室内空气相比，呼吸氦氧混合气时运动表现时间改善（527.6±38秒对531.3±36.9秒；P = 0.017），吸气（-22.8±11.6%，P < 0.001）和呼气（-10.8±11.4%，P = 0.003）过程中呼吸肌力发展下降。氦氧混合气时EFL趋于更低（潮气量的22±23%对30±23%；P = 0.054）。与二氧化碳产生量标准化的分钟通气量（[公式：见正文]/[公式：见正文]CO₂）在呼吸氦氧混合气时增加（28.6±2.7对25.1±1.8；P < 0.001）。运动后与运动前相比观察到最大吸气压力（MIP）和最大呼气压力（MEP）降低，但不同条件之间无差异。
尽管呼吸肌力发展有所下降，但在5公里计时赛中，呼吸氦氧混合气对高水平运动员的表现影响有限。
