Influence of localized auxiliary heating on hand comfort during cold exposure

Abstract

There is a need for a hand-heating system that will keep the hands warm during cold exposure without hampering finger dexterity. The purpose of this study was to examine the effects of torso heating on the vasodilative responses and comfort levels of cooled extremities during a 3-h exposure to -15 degreesC air. Subjects were insulated, but their upper extremities were left exposed to the cold ambient air. The effect of heating the torso [torso-heating test (THT)] on hand comfort was compared with a control condition in which no torso heating was applied, but Arctic mitts were worn [control test (CT)]. The results indicate that mean finger temperature, mean finger blood flow, mean toe temperature, mean body skin temperature, body thermal comfort, mean finger thermal comfort, and rate of body heat storage were all significantly (P < 0.05) higher on average (n = 6) during THT. Mean body heat flow was significantly (P < 0.05) lower during THT. There were no significant differences (P >/= 0.05) in rectal temperature between CT and THT. Mean unheated body skin temperature and mean unheated body heat flow (both of which did not include the torso area in the calculation of mean body skin temperature and mean body heat flow) were also calculated. There were no significant differences (P >/= 0.05) in mean unheated body skin temperature and mean unheated body heat flow between CT and THT. It is concluded that the application of heat to the torso can maintain finger and toe comfort for an extended period of time during cold exposure.

Hand-skin temperature and tracking performance

“…Brajkovic et al (1998) define the comfortable temperature for fingers to be greater than 23 0 C. In this study, we attempted to investigate how hand temperatures of 10, 20 and 30 0 C would affect tracking performance Oksa et al (1995) found that muscle performance as measured by mean IEMG activity decreased at a temperature of 10 0 C. Cooling slowed the function of the agonist muscle and decreased its IEMG activity but increased the IEMG activity of the antagonist muscle. Some researchers have reported that the endurance time of sustained, submaximal, voluntary 5 contractions of muscles are temperature dependent, being optimal at peripheral temperatures of 18-26 0 C (Clarke, Hellon and Lind, 1959).…”

Efficacy of Heated Glove Liners

“…Even the power supply for hand used during the study was, at present, too large and heavy for extended use. Brajovik et al [11] presented data supporting the use of torso heating rather than extremity heating. They also raised the issue of insidious hypothermia.…”

Effects of Air Velocity and Clothing Combination on Heating Efficiency of an Electrically Heated Vest (EHV): A Pilot Study

“…Previous studies [3][4][5] have proved that the heating efficiency and heating power are the two most important parameters that should be considered during the EHV design process. In this article, we studied the effects of air velocity and clothing combination on the heating efficiency in the cold environment by a thermal manikin.…”