Introduction

Drinking cold water evokes decreases in spirometric indices of lung function. We studied whether this could be explained by changes in exhaled-breath temperature (EBT), airflow dynamics, and spirometer measurement sensitivity.

Methods

In a randomized/crossover design, 10 healthy adults consumed 1000 mL refrigerated water (2.1 ± 0.64 °C) or water at room temperature (19.4 ± 0.5 °C), with EBT assessed at baseline and at 5, 10, 15 and 30-min post-ingestion. The influence of EBT on pneumotachograph measurement characteristics was modelled using computational fluid dynamics (CFD).

Results

At 5-min post-ingestion, EBT was lower (p < 0.001) following the ingestion of cold water versus water at room-temperature (31.7 ± 1.1 vs. 33.0 ± 0.9 °C), and remained lower until 30-min post-ingestion. At a flow of 8 L s^―1, a decrease in EBT of 2.1 °C (as observed following cold-water ingestion) was modelled to underpredict lung volume by 0.7%.

Conclusions

Cold water reduces EBT below baseline but effects pneumotachograph measurements only negligibly. Therefore, decreased lung function following cold-water ingestion likely has a physiological explanation which warrants further study.

中文翻译：

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摄入冷水后的气流动力学和呼气温度

介绍

喝冷水会引起肺功能的肺活量指标下降。我们研究了这是否可以通过呼气温度 (EBT)、气流动力学和肺活量计测量灵敏度的变化来解释。

方法

在随机/交叉设计中，10 名健康成年人饮用 1000 mL 冷冻水 (2.1 ± 0.64 °C) 或室温水 (19.4 ± 0.5 °C)，并在基线和 5、10、15 和 30-摄取后分钟。EBT 对呼吸速度描记器测量特性的影响使用计算流体动力学 (CFD) 建模。

结果

在摄入后 5 分钟，在摄入冷水与室温下的水（31.7 ± 1.1 对 33.0 ± 0.9 °C）后，EBT 较低（p < 0.001），并且在摄入后 30 分钟之前保持较低水平摄取。在 8 L s ^-1的流量下，EBT 降低 2.1 °C（如摄入冷水后观察到的）被模拟为低估肺容积 0.7%。

结论

冷水将 EBT 降低到基线以下，但对呼吸速度描记器测量的影响微乎其微。因此，摄入冷水后肺功能下降可能具有生理学解释，值得进一步研究。