Matsutake Ryoko, Fujimoto Tomomi, Ichinose Masashi, Watanabe Kazuhito, Fujii Naoto, Nishiyasu Takeshi
Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Ibaraki, 305-8574, Japan.
Department of Health and Sports, Niigata University of Health and Welfare, Niigata, Japan.
Eur J Appl Physiol. 2025 Apr;125(4):1179-1190. doi: 10.1007/s00421-024-05643-8. Epub 2024 Nov 26.
We evaluated (1) the combined effects of cold stimulation and voluntary breath holding (apnea) on heart rate, blood pressure, blood flow and vascular responses in dynamically exercising muscles in humans, and (2) if some interactions exist between cold stimulation and apnea on the cardiovascular responses.
Nine males and 1 female performed three trials entailing a dynamic two-legged knee extension exercise at a constant workload that elicited heart rates around 100 beats min. During the trials the participants performed either: (1) immersed their right hand into ice water maintained at 4 °C (cold pressor test; CPT); (2) performed maximal-duration apnea; and (3) performed a combination of CPT and apnea. Leg blood flow (LBF) and cardiac output (CO) were measured simultaneously using two Doppler ultrasound systems.
CPT induced a rise in mean arterial pressure (MAP) (P < 0.05) but had no significant effect on CO or exercising leg vascular conductance (LVC). Apnea evoked large pressor responses, bradycardia and decreases in CO, LBF and LVC (all P < 0.05). The increase in MAP induced by combined CPT and apnea was smaller than the sum of those induced separately by CPT or apnea (P < 0.05). Combined CPT and apnea decreased LBF and LVC to a similar extent as apnea alone.
Addition of local cold stimulation to apnea does not enhance pressor responses or vasoconstriction within active muscles. This suggests that maximum voluntary apnea evokes massive vasoconstriction, even within exercising muscles, which cannot be enhanced by additional sympathetic stimulation.
我们评估了（1）冷刺激和主动屏气（呼吸暂停）对人体动态运动肌肉的心率、血压、血流和血管反应的联合影响，以及（2）冷刺激和呼吸暂停在心血管反应方面是否存在一些相互作用。
9名男性和1名女性进行了三项试验，在恒定工作量下进行动态双腿膝关节伸展运动，使心率维持在每分钟100次左右。在试验过程中，参与者分别进行：（1）将右手浸入4℃的冰水中（冷加压试验；CPT）；（2）进行最长时间的屏气；（3）同时进行CPT和屏气。使用两个多普勒超声系统同时测量腿部血流量（LBF）和心输出量（CO）。
CPT导致平均动脉压（MAP）升高（P < 0.05），但对CO或运动腿部血管传导率（LVC）无显著影响。屏气引起强烈的升压反应、心动过缓以及CO、LBF和LVC降低（均P < 0.05）。CPT和屏气联合引起的MAP升高小于CPT或屏气单独引起的升高之和（P < 0.05）。CPT和屏气联合使LBF和LVC降低的程度与单独屏气相似。
在屏气时添加局部冷刺激不会增强活跃肌肉内的升压反应或血管收缩。这表明最大程度的主动屏气即使在运动肌肉内也会引起大量血管收缩，额外的交感神经刺激无法增强这种收缩。
