Asymmetries of oxygen uptake transients at the on‐ and offset of heavy exercise in humans.
Asymmetries of oxygen uptake transients at the on‐ and offset of heavy exercise in humans.
复制标题
人类剧烈运动开始和结束时摄氧瞬变的不对称性。
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
B. Whipp
中科院分区：
文献类型：
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作者：
D. H. Paterson;B. Whipp
1. 在不会导致血乳酸 ([L-]) 持续增加的工作速率下，摄氧量 (VO2) 接近一级动力学稳态。然而，当 [L-] 增加时，至少需要两个动力学分量来表征 VO2 响应动力学。本研究的目的是确定这些更复杂的动力学是否最好表示为：（a）在整个运动过程中起作用的两个成分或（b）乳酸血症导致的延迟缓慢成分，并且不影响氧气缺乏的早期发展。 2. 六名健康受试者在自行车测力计上进行增量斜坡测试，直至达到耐受极限，以无创地确定最大摄氧量（微摄氧量）和估计[符号：参见文本]乳酸血症阈值 (theta L)。然后，受试者在不同的日子里，从空载踩踏基线（“O”瓦（W））到小于 θ L（90% θ L）和大于 θ L（θ L 和微摄氧量之间的中间值）的工作速率（WR），重复进行两到四次方波运动。通气和肺部气体交换变量是通过每次呼吸来确定的。对于每个受试者，在将最小二乘算法拟合到开启和关闭瞬态响应之前，对 VO2 转换进行平均。 3. 小于 theta L 测试导致单指数 VO2 响应，开瞬态和关瞬态的时间常数分别为 31.3 秒和 31.5 秒。 4. 将 VO2 对大于 theta L 测试的响应拟合到三个竞争模型： (a) 整个周期的单个指数； (b) 整个时期的双指数； (c) 初始单指数，后续阶段为延迟发作。模型 (c) 产生的残余均方误差显着低于方法 (a) 和 (b)，初始分量的时间常数为 40.2 s（瞬态）和 32.9 s（非瞬态），后续阶段的 VO2 增加（瞬态）平均为 230 ml min-1。大于 theta L 测试的早期动力学的 delta VO2/delta WR 与小于 theta L 测试没有不同（分别为 9.6 和 9.5 ml min-1 W-1）。 5. 这些数据表明大于 θ L VO2 动力学的慢相是一个延迟发生的过程。在这种情况下，传统上估计的剧烈运动期间的氧气不足就会被高估。
1. At work rates which do not result in a sustained increase in blood lactate ([L‐]), oxygen uptake (VO2) approaches the steady state with first‐order kinetics. However, when [L‐] is increased, at least two kinetic components are required to characterize the VO2 response dynamics. The purpose of the present investigation was to determine whether these more‐complex kinetics are best represented as: (a) two components which operate throughout the exercise or (b) a delayed slow component which is consequent to the lactic acidaemia and which does not influence the early development of the O2 deficit. 2. Six healthy subjects underwent an incremental ramp test on a cycle ergometer, to the limit of tolerance, for determination of the maximum VO2 (micro VO2) and and estimation [symbol: see text] of the threshold for lactic acidaemia (theta L) non‐invasively. Subjects then performed, on different days, two to four repetitions of square‐wave exercise from a baseline of unloaded pedalling ('O' Watts (W)) to work rates (WR) less than theta L (90% theta L) and greater than theta L (half‐way between theta L and micro VO2). Ventilatory and pulmonary gas exchange variables were determined breath‐by‐breath. For each subject, the VO2 transitions were averaged prior to fitting a least‐squares algorithm to the on‐ and off‐transient responses. 3. The less than theta L test resulted in a mono‐exponential VO2 response, with a time constant of 31.3 and 31.5 s for the on‐ and off‐transients, respectively. 4. The VO2 responses to the greater than theta L test were fitted to three competing models: (a) a single exponential for the entire period; (b) a double exponential for the entire period; and (c) an initial single exponential with a subsequent phase of delayed onset. Model (c) yielded a significantly lower residual mean‐squares error than methods (a) and (b), with a time constant for the initial component of 40.2 s for the on‐transient and 32.9 s for the off‐transient and a subsequent phase of VO2 increase for the on‐transient which averaged 230 ml min‐1. The delta VO2/delta WR for the early kinetics of the greater than theta L test were not different from the less than theta L test (9.6 and 9.5 ml min‐1 W‐1, respectively). 5. These data suggest that the slow phase of the greater than theta L VO2 kinetics is a delayed‐onset process. This being the case, the O2 deficit during heavy exercise, as conventionally estimated, would be overestimated.
肾上腺素的生理增加会刺激人体的新陈代谢率。
DOI：
10.1152/ajpendo.1987.253.3.e322
发表时间：
1987
期刊：
The American journal of physiology
影响因子：
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作者：
Staten,MA;Matthews,DE;Cryer,PE;Bier,DM
通讯作者：
Bier,DM