Efficacy of wrist/palm warming as an EVA countermeasure to maintain finger comfort in cold conditions.Aviat Space Environ Med. 2001 Aug; 72(8):713-9.AS
This study explored the effectiveness of local wrist/palm warming as a potential countermeasure for providing finger comfort during extended duration EVA.
There were six subjects (five males and one female) who were evaluated in a liquid cooling/warming garment (LCWG) wearing modified liquid cooling/warming (LCW) gloves in three different experimental conditions: Condition 1: Stage 1--no LCWG, LCW glove inlet water temperature 33 degrees C; Stage 2--no LCWG, LCW glove inlet water temperature cooled to 8 degrees C; Stage 3--no LCWG, LCW glove inlet water temperature warmed to 45 degrees C; Condition 2: Stage 1--LCWG and LCW glove inlet water temperature 33 degrees C; Stage 2--LCWG inlet temperature cooled to 31 degrees C, LCW gloves, 8 degrees C; Stage 3--LCWG inlet water temperature remains at 31 degrees C, LCW glove inlet water temperature warmed to 45 degrees C; Condition 3: Stage 1--LCWG and LCW gloves 33 degrees C; Stage 2--LCWG inlet water temperature cooled to 28 degrees C, LCW gloves, 8 degrees C; Stage 3--LCWG remains at 28 degrees C, LCW glove water temperature warmed to 45 degrees C.
Wrist/palm area warming showed a statistically significant increase in finger temperature (Tfing) in Stage 3 compared with Stage 2. Blood perfusion showed a trend toward a significantly greater value in Stage 3 compared with Stage 2. The LCW gloves were significantly more effective in increasing Stage 3 Tfing in Condition 1 (33 degrees C) compared with Condition 3 (28 degrees C). Across conditions, subjective perception of heat in the hands was significantly greater at Stage 3 than Stage 2; perception of overall body heat showed a trend for higher heat ratings in Stage 3 than Stage 2.
Local wrist/palm warming was effective in increasing blood circulation to the distal upper extremities, suggesting the potential usefulness of this technique for enhancing astronaut comfort during EVA while decreasing power requirements.