Face temperature and cardiorespiratory responses to wind in thermoneutral and cool subjects exposed to -10 °C
Research output: Contribution to journal › Article
The effects of the thermal state of the body (slightly cool and neutral) and moderate wind speeds on face temperature, blood pressure, respiratory function and pain sensation during cold exposure were studied on eight healthy male subjects. They were dressed in cold-protective clothing and preconditioned at +20 °C (TN) and m5 °C (CO) for 60 min, then exposed to m10 °C and 0 m · sm1 (NoW), 1 (W1) and 5 (W5) m · sm1 wind for 30 min. Thus, each individual was exposed six times. The exposure to wind entailed a combination of strong cooling of the bare face and mild body cooling. The forehead, cheek and nose temperatures decreased during cold exposure, and the decrease was greater at higher air velocities (P < 0.0001). All subjects reported pain sensations at 5 m · sm1. At the end of exposure only the nose temperature was significantly lower in CO than in TN subjects; it was about 2 °C and reached 0 °C in two experiments. The systolic and diastolic blood pressure (SBP and DBP, respectively) increased significantly by 7.7 and 5.9 mmHg, respectively, during preconditioning at m5 °C, but did not change at +20 °C. SBP and DBP increased during exposure to m10 °C in TN by approximately 9 mmHg. However, the total average increase of blood pressure (1-90 min) was similar in TN and CO (SBP 15 mmHg and DBP 13 mmHg). SBP and DBP increased more during exposure to 5 m · sm1 at m10 °C than NoW. Blood pressure responses as observed in this study (SBP and DBP up to 51 and 45 mmHg, respectively) are potential health risks for hypertensive individuals and angina patients. Respiratory functions (FVC, FEV1) were reduced by about 3% by the cold (m5 and m10 °C) compared to pre-experiment values. Furthermore, the Wind Chill Index seems to underestimate the cooling power of 5 m · sm1 at m10 °C of bare skin (e.g. face). Therefore it needs to be revised and we suggest that it is expanded to include risk levels for pain sensation.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||European Journal of Applied Physiology|
|Publication status||Published - 2000|