Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
Department of Science and Health, Institute of Technology Carlow, Carlow, Ireland.
Respir Res. 2022 May 12;23(1):121. doi: 10.1186/s12931-022-02029-2.
Strenuous endurance exercise in sub-zero temperatures can cause airway damage that may lead to EIB. Prolonged exercise can also elicit greater immune perturbations than short-duration exercise. However, the influence of exercise duration on lung function and systemic immunity in sub-zero temperatures has not been established. Additionally, it is currently unknown whether atopic disposition, which is risk factor for EIB, influences respiratory responses in a sub-zero climate. The aim of this study was to compare respiratory and systemic immune responses to two cold air running trials of short and long duration, as well as to examine whether the responses differed between atopic and non-atopic subjects.
Eighteen healthy, endurance-trained subjects (males/females: 14/4; age: 29.4 ± 5.9 years old; BMI: 23.1 ± 1.7; atopic/non-atopic: 10/8) completed two moderate-intensity climate chamber running trials at - 15 °C, lasting 30 and 90 min, in a randomized, cross-over design. Lung function (spirometry and impulse oscillometry), serum CC16, respiratory symptoms, and blood leukocyte counts were examined before and after the trials.
Lung function was not significantly affected by exercise or exercise duration. CC16 concentration increased after both trials (p = 0.027), but the response did not differ between trials. Respiratory symptom intensity was similar after each trial. There was a greater increase in neutrophils (p < 0.001), and a decrease in eosinophils (p < 0.001) after the 90-min bout. The 90-min protocol increased X5 compared to the 30-min protocol only in atopic subjects (p = 0.015) while atopy increased lower airway symptoms immediately after the 90-min session (p = 0.004).
Our results suggest that a 90-min bout of moderate-intensity exercise at - 15 °C does not cause substantial lung function decrements, airway epithelial damage or respiratory symptoms compared to 30 min running in the same environment, despite a heightened redistribution of white blood cells. However, exercise at - 15 °C may cause airway injury and evoke respiratory symptoms, even at moderate intensity. Atopic status may lead to greater peripheral bronchodilation and higher frequency of respiratory symptoms after long-duration exercise in cold.
01/02/2022 ISRCTN13977758. This trial was retrospectively registered upon submission to satisfy journal guidelines. The authors had not initially registered the study, as the intervention was considered to be a controlled simulation of exercise in a naturally occurring environment (i.e. sub-zero air) for healthy volunteers.
在亚低温环境下进行剧烈的耐力运动可能会导致气道损伤，从而导致 EIB。长时间运动比短时间运动更能引起更大的免疫紊乱。然而，在亚低温下运动持续时间对肺功能和全身免疫的影响尚未确定。此外，目前尚不清楚特应性倾向（EIB 的危险因素）是否会影响亚低温气候下的呼吸反应。本研究的目的是比较两种短时间和长时间冷空气跑步试验对呼吸和全身免疫的影响，并研究特应性和非特应性受试者的反应是否存在差异。
18 名健康的耐力训练受试者（男性/女性：14/4；年龄：29.4±5.9 岁；BMI：23.1±1.7；特应性/非特应性：10/8）在-15°C 的气候室中以随机交叉设计完成两次中等强度的跑步试验，持续时间分别为 30 和 90 分钟。在试验前后检查肺功能（肺活量和脉冲振荡）、血清 CC16、呼吸症状和白细胞计数。
运动或运动持续时间对肺功能没有显著影响。两次试验后 CC16 浓度均升高（p=0.027），但两次试验之间的反应没有差异。每次试验后的呼吸症状强度相似。90 分钟运动后中性粒细胞（p<0.001）增加，嗜酸性粒细胞（p<0.001）减少。与 30 分钟方案相比，90 分钟方案仅在特应性受试者中增加 X5（p=0.015），而特应性在 90 分钟运动后立即增加下气道症状（p=0.004）。
我们的结果表明，与在相同环境中进行 30 分钟跑步相比，-15°C 下进行 90 分钟中等强度运动不会导致明显的肺功能下降、气道上皮损伤或呼吸症状，尽管白细胞重新分布增加。然而，即使在中等强度下，在寒冷环境中进行长时间运动也可能导致气道损伤并引起呼吸症状。特应性状态可能导致长时间运动后外周支气管扩张和呼吸症状的频率增加。
2022 年 1 月 2 日 ISRCTN8650640。本试验在提交后进行了回顾性登记，以满足期刊指南的要求。作者最初并未对该研究进行登记，因为该干预措施被认为是对健康志愿者在自然发生的环境（即亚低温空气）中进行运动的对照模拟。
