AJP - Endocrinology and Metabolism, Vol 263, Issue 6 E1040-E1045, Copyright © 1992 by American Physiological Society
Effect of moderate cold exposure on 24-h energy expenditure: similar response in postobese and nonobese women
B. Buemann, A. Astrup, N. J. Christensen and J. Madsen
Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Frederiksberg, Copenhagen, Denmark.
Twenty-four-hour energy expenditure (EE) and substrate oxidation rates were
measured two times in eight postobese women and eight matched controls. On
one occasion the subjects were exposed to a room temperature of 16 degrees
C, on the other to 24 degrees C. Cold exposure elicited a 2% increment in
24-h EE (P < 0.05), with similar response in the two groups. The slight
increase in EE was entirely covered by an enhanced carbohydrate oxidation
rate. Fasting plasma norepinephrine (NE) increased from 0.74 +/- 0.08 to
1.29 +/- 0.21 nmol/l under cold exposure (P < 0.05), with no group
difference. The cold-induced increase in 24-h EE was positively correlated
to the increase in NE concentration (r2 = 0.41, P = 0.01). Sleeping EE was
found to be 5% lower in the postobese women than in the controls (P =
0.04). The postobese group also had higher 24-h nonprotein respiratory
quotient than the control group (P = 0.04), which was due to a 26% lower
lipid-to-carbohydrate oxidation ratio. The study demonstrates that the
thermogenic response to cold is normal in women susceptible to obesity, but
it supports previous reports of a slightly lower basal EE and lower
lipid-to-carbohydrate oxidation ratio in postobese subjects.
