Mild body cooling impairs attention via distraction from skin cooling

Abstract

Many contemporary workers are routinely exposed to mild cold stress, which may compromise mental function and lead to accidents. A study investigated the effect of mild body cooling of 1.0°C rectal temperature (T_re) on vigilance (i.e. sustained attention) and the orienting of spatial attention (i.e. spatially selective processing of visual information). Vigilance and spatial attention tests were administered to 14 healthy males and six females at four stages (pre-immersion, ΔT_re = 0, −0.5 and −1.0°C) of a gradual, head-out immersion cooling session (18–25°C water), and in four time-matched stages of a contrast session, in which participants sat in an empty tub and no cooling took place. In the spatial attention test, target discrimination times were similar for all stages of the contrast session, but increased significantly in the cooling phase upon immersion (ΔT_re = 0°C), with no further increases at ΔT_re = −0.5 and −1.0°C. Despite global response slowing, cooling did not affect the normal pattern of spatial orienting. In the vigilance test, the variability of detection time was adversely affected in the cooling but not the contrast trials: variability increased at immersion but did not increase further with additional cooling. These findings suggest that attentional impairments are more closely linked to the distracting effects of cold skin temperature than decreases in body core temperature.

Keywords:

• Spatial attention
• Vigilance
• Cognition
• Skin temperature
• Core temperature
• Thermal strain

Acknowledgements

The authors wish to express their gratitude to the participants who participated in the experiments. Technical assistance throughout this study was provided by T. Mammen and M.S. Grandy. The infrastructure was supported by Canada Foundation for Innovation (New Opportunities) and the study was supported by the Cold Working Conditions group of SafetyNet: A Community Alliance for Health & Safety in Marine & Coastal Work, an initiative of the Canadian Institutes for Health Research. M. Knox was supported by a research assistantship from the Natural Sciences and Engineering Research Council (NSERC).