Barwood Martin J, Eglin Clare, Hills Samuel P, Johnston Nicola, Massey Heather, McMorris Terry, Tipton Michael J, Wakabayashi Hitoshi, Webster Lisa
Faculty of Social and Health Sciences, Leeds Trinity University, Horsforth, UK.
School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK.
J Therm Biol. 2024 Jan;119:103775. doi: 10.1016/j.jtherbio.2023.103775. Epub 2023 Dec 27.
Cold water immersion (CWI) evokes the life-threatening reflex cold shock response (CSR), inducing hyperventilation, increasing cardiac arrhythmias, and increasing drowning risk by impairing safety behaviour. Repeated CWI induces CSR habituation (i.e., diminishing response with same stimulus magnitude) after ∼4 immersions, with variation between studies. We quantified the magnitude and coefficient of variation (CoV) in the CSR in a systematic review and meta-analysis with search terms entered to Medline, SportDiscus, PsychINFO, Pubmed, and Cochrane Central Register. Random effects meta-analyses, including effect sizes (Cohen's d) from 17 eligible groups (k), were conducted for heart rate (HR, n = 145, k = 17), respiratory frequency (f, n = 73, k = 12), minute ventilation (V, n = 106, k = 10) and tidal volume (V, n = 46, k=6). All CSR variables habituated (p < 0.001) with large or moderate pooled effect sizes: ΔHR -14 (10) bt. min (d: -1.19); Δf -8 (7) br. min (d: -0.78); ΔV, -21.3 (9.8) L. min (d: -1.64); ΔV -0.4 (0.3) L . Variation was greatest in V (control vs comparator immersion: 32.5&24.7%) compared to V (11.8&12.1%). Repeated CWI induces CSR habituation potentially reducing drowning risk. We consider the neurophysiological and behavioural consequences.
冷水浸泡（CWI）会引发危及生命的反射性冷休克反应（CSR），导致呼吸急促、心律失常增加，并通过损害安全行为增加溺水风险。重复进行冷水浸泡在约4次浸泡后会引起冷休克反应习惯化（即相同刺激强度下反应减弱），但不同研究之间存在差异。我们在一项系统评价和荟萃分析中，通过在Medline、SportDiscus、PsychINFO、Pubmed和Cochrane中央注册库中输入检索词，对冷休克反应的强度和变异系数（CoV）进行了量化。对心率（HR，n = 145，k = 17）、呼吸频率（f，n = 73，k = 12）、分钟通气量（V，n = 106，k = 10）和潮气量（V，n = 46，k = 6）进行了随机效应荟萃分析，纳入了17个符合条件的组（k）的效应量（Cohen's d）。所有冷休克反应变量均出现习惯化（p < 0.001），合并效应量为大或中等：ΔHR -14（10）次/分钟（d：-1.19）；Δf -8（7）次/分钟（d：-0.78）；ΔV，-21.3（9.8）升/分钟（d：-1.64）；ΔV -0.4（0.3）升。与潮气量（11.8%和12.1%）相比，分钟通气量的变异最大（对照组与比较组浸泡：32.5%和24.7%）。重复进行冷水浸泡会引起冷休克反应习惯化，可能降低溺水风险。我们考虑了神经生理学和行为学后果。
