Effect of moderate cold exposure on 24-h energy expenditure: similar response in postobese and nonobese women.
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.
Buemann
B
B
Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Frederiksberg, Copenhagen, Denmark.
Astrup
A
A
Christensen
N J
NJ
Madsen
J
J
D000328:Adult; D002151:Calorimetry; D002940:Circadian Rhythm; D003080:Cold Temperature; D004734:Energy Metabolism; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D009043:Motor Activity; D009638:Norepinephrine / Q000097:blood; D009765:Obesity / Q000097:blood / Q000378:metabolism / Q000628:therapy*; D012016:Reference Values; D012119:Respiration; D015431:Weight Loss
D005230:Fatty Acids, Nonesterified; D009638:Norepinephrine; D004837:Epinephrine