Sejersen Casper, Rocha Marcos P, Van Lieshout Johannes J, Secher Niels H
Department of Anaesthesia, Rigshospitalet 2043, Institute for Clinical Medicine, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
Eur J Appl Physiol. 2021 Nov;121(11):3061-3067. doi: 10.1007/s00421-021-04772-8. Epub 2021 Jul 24.
During cycling, the variation in cardiac stroke volume (SVV) is similar to that at rest. However, SVV may be influenced by ventilation at the start of cycling, e.g., by a Valsalva-like maneuver used to stabilize the body. This study evaluated the influence of ventilation on SV during initiation of cycling.
Ten healthy recreationally physical active males (mean ± SD: age 26 ± 3 years, height 184 ± 9 cm, weight 85 ± 9 kg) cycled on an ergometer for four 30 s intervals at submaximal workloads while synchronizing ventilatory and cardiovascular variables derived from gas exchange and arterial pulse contour analysis, respectively.
At exercise onset, cardiac output increased by an instantaneous rise in heart rate and SV (P < 0.05). In contrast, blood pressure increased only after 15 s (P < 0.05), reflected in a decline in total peripheral resistance from exercise onset (P < 0.05). SVV was similar at rest (20 ± 6%) and during exercise (21 ± 5%) except for the first 5 s of exercise when a ~ 2.5-fold elevation (47 ± 6%; P < 0.05) was correlated to variation in respiratory frequency (= 0.71, P = 0.02) and tidal volume (R = 0.66, P = 0.04) but not to variation in heart rate or blood pressure. Stepwise multiple regression analysis indicated a respiratory frequency influence on SVV at the onset of ergometer cycling.
The data provide evidence for a ventilatory influence on SVV at the onset of cycling exercise.
在骑行过程中，心搏量（SVV）的变化与静息时相似。然而，SVV可能在骑行开始时受到通气的影响，例如通过类似瓦尔萨尔瓦动作来稳定身体。本研究评估了通气对骑行开始时SV的影响。
10名健康的有休闲体育活动习惯的男性（平均±标准差：年龄26±3岁，身高184±9厘米，体重85±9千克）在测力计上以次最大负荷进行4次30秒的骑行，同时分别同步来自气体交换和动脉脉搏轮廓分析的通气和心血管变量。
运动开始时，心输出量因心率和SV的瞬时升高而增加（P<0.05）。相比之下，血压仅在15秒后升高（P<0.05），这反映在运动开始时总外周阻力下降（P<0.05）。静息时（20±6%）和运动期间（21±5%）的SVV相似，但运动的前5秒除外，此时约2.5倍的升高（47±6%；P<0.05）与呼吸频率变化（=0.71，P=0.02）和潮气量变化（R=0.66，P=0.04）相关，但与心率或血压变化无关。逐步多元回归分析表明，测力计骑行开始时呼吸频率对SVV有影响。
数据为骑行运动开始时通气对SVV的影响提供了证据。
