Thermal comfort and clothing insulation of resting tent occupants at high altitude
Thirty-nine males and 18 females, in six groups, participated in six high altitude treks (each lasting 34 weeks and climbing up to 5500m) in the Himalaya and Karakoram. Inverse relationships between mean overnight total insulation (sleeping bag plus clothing) and air temperature in tents were recorded for all treks. Average overnight thermal sensations varied little with air temperature as the subjects modified their clothing insulation to maintain thermal sensations warmer than neutral for all treks. For combined treks, subjects adjusted their mean overnight total insulation up to 7clo for thermal sensations of between 0 (neutral) and +1 (slightly warm) on average, measured on the standard seven-point thermal sensation scale developed for everyday low-altitude conditions. Very few subjects (3% of all daily responses, on average) reported cool or cold sensations. General tent discomfort increased with altitude suggesting that subjects interpreted tent comfort predominantly in terms of thermal outdoor conditions.
thermal comfort tents high altitude