TABLE 9-2Estimates of Ambient Temperature and Metabolic Rate Effects on Respiratory Water Loss

Temperature
(°F [°C])		Relative
Humidity (%)		Water Vapor
(mm Hg)		Metabolic Rate
(watts)		Respiratory
Water (ml/h)
77 (25)6515Rest (100)~ 10
32 (0)1005Rest (100)~ 13
-4 (-20)1001Rest (100)~ 15
77 (25)6515Light–moderate (300)~ 30
32 (0)1005Light–moderate (300)~ 40
-4 (-20)1001Light–moderate (300)~ 45
77 (25)6515Moderate–heavy (600)~ 60
32 (0)1005Moderate–heavy (600)~ 80
-4 (-20)1001Moderate–heavy (600)~ 90
Total respiratory loss following 8-h rest, 12-h light–moderate activity, and 4-h moderate–heavy activity:
77 (25)65~ 680 ml/24 h
32 (0)100~ 905 ml/24 h
-4 (-20)100~ 1,020 ml/24 h

NOTE: Effect of cold air itself could account for increased respiratory water losses as great as 340 ml/24 h, i.e., 50 percent increase.

From: 9, Influence of Cold Stress on Human Fluid Balance

Cover of Nutritional Needs In Cold And In High-Altitude Environments
Nutritional Needs In Cold And In High-Altitude Environments: Applications for Military Personnel in Field Operations.
Institute of Medicine (US) Committee on Military Nutrition Research; Marriott BM, Carlson SJ, editors.
Washington (DC): National Academies Press (US); 1996.
Copyright 1996 by the National Academy of Sciences. All rights reserved.

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