Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland.
Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
Eur J Appl Physiol. 2022 Nov;122(11):2343-2354. doi: 10.1007/s00421-022-05011-4. Epub 2022 Jul 21.
We hypothesised that, during a light-to-moderate exercise transient, compared to an equivalent rest-to-exercise transient, (1) a further baroreflex sensitivity (BRS) decrease would be slower, (2) no rapid heart rate (HR) response would occur, and (3) the rapid cardiac output (CO) response would have a smaller amplitude (A1). Hence, we analysed the dynamics of arterial baroreflexes and the HR and CO kinetics during rest-to-50 W (0-50 W) and 50-to-100 W (50-100 W) exercise transients.
10 subjects performed three 0-50 W and three 50-100 W on a cycle ergometer. We recorded arterial blood pressure profiles (photo-plethysmography) and R-to-R interval (RRi, electrocardiography). The former were analysed to obtain beat-by-beat mean arterial pressure (MAP) and stroke volume (SV). CO was calculated as SV times HR. BRS was measured by modified sequence method.
During 0-50 W, MAP transiently fell (- 9.0 ± 5.7 mmHg, p < 0.01) and BRS passed from 15.0 ± 3.7 at rest to 7.3 ± 2.4 ms mmHg at 50 W (p < 0.01) promptly (first BRS sequence: 8.1 ± 4.6 ms mmHg, p < 0.01 vs. rest). During 50-100 W, MAP did not fall and BRS passed from 7.2 ± 2.6 at 50 W to 3.3 ± 1.3 ms mmHg at 100 W (p < 0.01) slowly (first BRS sequence: 5.3 ± 3.1 ms mmHg, p = 0.07 vs. 50 W). A1 for HR was 9.2 ± 6.0 and 6.0 ± 4.5 min in 0-50 W and 50-100 W, respectively (p = 0.19). The corresponding A1 for CO were 2.80 ± 1.54 and 0.91 ± 0.55 l∙min (p < 0.01).
During 50-100 W, with respect to 0-50 W, BRS decreased more slowly, in absence of a prompt pressure decrease. BRS decrease and rapid HR response in 50-100 W were unexpected and ascribed to possible persistence of some vagal tone at 50 W.
我们假设，在轻到中度运动的瞬间，与等效的休息到运动的瞬间相比，（1）血压反射敏感性（BRS）的进一步下降会更缓慢，（2）不会出现快速心率（HR）反应，以及（3）快速心输出量（CO）反应的幅度（A1）会更小。因此，我们分析了休息到 50W（0-50W）和 50 到 100W（50-100W）运动瞬间的动脉血压反射和 HR 和 CO 动力学。
10 名受试者在自行车测力计上进行了三次 0-50W 和三次 50-100W 的运动。我们记录了动脉血压谱（光容积描记术）和 R 到 R 间隔（RRi，心电图）。前者用于分析获得逐拍平均动脉压（MAP）和每搏输出量（SV）。CO 计算为 SV 乘以 HR。BRS 通过改良序列法测量。
在 0-50W 期间，MAP 短暂下降（-9.0±5.7mmHg，p<0.01），BRS 从休息时的 15.0±3.7 迅速转变为 50W 时的 7.3±2.4msmmHg（p<0.01）（第一 BRS 序列：8.1±4.6msmmHg，p<0.01 vs. 休息）。在 50-100W 期间，MAP 没有下降，BRS 从 50W 时的 7.2±2.6 转变为 100W 时的 3.3±1.3msmmHg（p<0.01）缓慢转变（第一 BRS 序列：5.3±3.1msmmHg，p=0.07 vs. 50W）。0-50W 和 50-100W 时 HR 的 A1 分别为 9.2±6.0 和 6.0±4.5min（p=0.19）。相应的 CO 的 A1 分别为 2.80±1.54 和 0.91±0.55l∙min（p<0.01）。
在 50-100W 期间，与 0-50W 相比，BRS 下降更缓慢，而没有明显的压力下降。50-100W 时 BRS 下降和快速 HR 反应出乎意料，归因于 50W 时可能存在一些迷走神经张力。
