Metabolic response to cold air in men and women in relation to total body fat content.

Eight healthy young men (ages 19–35), four older men (ages 38–42), three obese subjects (two women and one man, ages 20–34) were individually exposed on one or more occasions to 10 C (50 F) air in the Metabolic Chamber for periods of 2–4 hr. A minimal amount of clothing was worn: the males wore shorts and the females wore halters and shorts. Air movement was routinely less than 50 ft/min and relative humidity 50% or less. Body fatness among the subjects ranged from 13 to 45% of body weight. The metabolic response to cold determined from Vo2 and Vco2 was significantly and inversely related to per cent body fat according to the regression equation: kcal/(m2·hr) = 65.2 – 0.520 (% fat) ± 0.115. Total body insulation after 2 hr of exposure was significantly and directly related to per cent body fat and inversely related to the metabolic response. Despite these significant relationships, wide individual differences were observed in the metabolic response to cold between pairs of subjects of like age, previous history of cold exposure, and body fatness.