Purpose

This study seeks to evaluate effects of expectations and conditioning on dry breath holding.

Methods

Sixty healthy volunteers were subdivided into 3 groups and were tested across 4 breath holding trials. Participants of the Control group (C) did not undergo any manipulation. Participants of the placebo (P) and nocebo (N) groups were told that they would inhale O2 (actually sham O2) or CO2 (actually sham CO2) along with opposite information that this would enhance or worsen their breath holding time, respectively. Opposite conditioning paradigms based on false visual feedback were employed to reinforce participants’ positive (placebo) and negative (nocebo) beliefs.

Results

The P group showed the greater increase in breath holding time from baseline to the last trial (p = 0.0001) and the longest breath holding time in the last trial compared to the C group (p = 0.02) and the N group (p = 0.0001). Additionally, in the last trial the P group showed a greater decrease in peripheral oxygen saturation (SpO2) as compared to the C group (p = 0.04) and the N group (p = 0.001). Heart rate (HR) was accelerated in the N group during breath holding (in comparison to the P group [p = 0.04] and C group [p = 0.04]).

Conclusions

Psychological components can affect behavioral and physiological parameters in breath holding. This study may inform future research about the role of placebo and nocebo effects for conditions in which critical functions are at play.

中文翻译：

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屏气的安慰剂效应：初步行为研究

目的

这项研究旨在评估预期和条件对口干气息的影响。

方法

60名健康志愿者被分为3组，并在4次屏气试验中接受了测试。对照组（C）的参与者未进行任何操作。安慰剂（P）和Nocebo（N）组的参与者被告知他们将吸入O2（实际上是假氧气）或CO2（实际上是假二氧化碳）以及相反的信息，分别会增加或恶化他们的屏气时间。使用基于错误视觉反馈的相反条件范式来增强参与者的积极（安慰剂）和消极（nocebo）信念。

结果

与C组（p = 0.02）和N组（p = 0.0001）相比，P组显示从基线到上次试验的屏气时间增加更大（p = 0.0001），并且在上次试验中最长的屏气时间更长。 ）。此外，在最后的试验中，与C组（p = 0.04）和N组（p = 0.001）相比，P组的外周血氧饱和度（SpO2）降低更大。N组屏气期间心率（HR）加快（与P组[p = 0.04]和C组[p = 0.04]相比）。

结论

心理成分会影响屏气的行为和生理参数。这项研究可能会为将来在关键功能发挥作用的条件下安慰剂和Nocebo效应的作用提供信息。