Kennard C D, Martin B J
Eur J Appl Physiol Occup Physiol. 1984;52(3):320-3. doi: 10.1007/BF01015218.
Although many studies indicate that the spontaneous breathing frequency minimizes breathing work, the consequences of this for exercise energetics have never been investigated. To see if the spontaneous exercise breathing frequency minimizes oxygen uptake, we compared VO2 during treadmill walking (2/3 VO2 max) at several alternative frequencies. The alternative frequencies ranged from the lowest sustainable to a frequency twice the spontaneous value. All eight subjects adjusted tidal volume to comfort. Exercise oxygen uptake was constant, independent of breathing frequency. At the same time, minute ventilation rose to be 65% greater at the highest frequency than at the lowest (P less than 0.01). We then reproduced the various exercise frequencies, tidal volumes, and ventilations during seated isocapnic hyperpnea to measure VO2 with locomotory muscles at rest. Once again, oxygen uptake was constant, independent of breathing frequency. We conclude that the spontaneous exercise breathing frequency fails to minimize VO2 during either exercise or resting reproduction of exercise ventilation.
尽管许多研究表明，自主呼吸频率可使呼吸功最小化，但这对运动能量代谢的影响从未被研究过。为了探究自主运动呼吸频率是否能使摄氧量最小化，我们比较了在跑步机上以几种不同频率行走（2/3最大摄氧量）时的VO₂。这些不同频率范围从最低可持续频率到自发频率的两倍。所有八名受试者都将潮气量调整至舒适状态。运动摄氧量保持恒定，与呼吸频率无关。与此同时，最高频率时的分钟通气量比最低频率时高65%（P小于0.01）。然后，我们在坐位等碳酸血症性通气过度期间重现了各种运动频率、潮气量和通气量，以测量静息状态下运动肌肉的VO₂。再一次，摄氧量保持恒定，与呼吸频率无关。我们得出结论，无论是在运动期间还是在运动通气的静息重现过程中，自主运动呼吸频率都无法使VO₂最小化。
