Minimal changes in environmental temperature result in a significant increase in energy expenditure and changes in the hormonal homeostasis in healthy adults.
OBJECTIVE
Resting energy expenditure (EE) is a major contributor to the total EE and thus plays an important role in body weight regulation. Adaptive thermogenesis is a major component of EE in rodents, but little is known on the effects of exposure of humans to mild and sustainable reduction in environmental temperature.


METHODS
To characterize the dynamic changes in continuously measured resting EE, substrate utilization, and hormonal axes simultaneously in response to mild reduction in environmental temperature, we performed a cross-over intervention.


METHODS
Twenty-five volunteers underwent two 12-h recordings of EE in whole room indirect calorimeters at 24 and 19 °C with simultaneous measurement of spontaneous movements and hormonal axes.


RESULTS
Exposure to 19 °C resulted in an increase in plasma and urine norepinephrine levels (P<0.0001), and a 5.96% (P<0.001) increase in EE without significant changes in spontaneous physical activity. Exposure to the lower temperature resulted in a significant increase in free fatty acid levels (P<0.01), fasting insulin levels (P<0.05), and a marginal decrease in postprandial glucose levels. A small but significant (P<0.002) increase in serum free thyroxine and urinary free cortisol (P<0.05) was observed at 19 °C.


CONCLUSIONS
Our observations indicate that exposure to 19 °C, a mild and tolerable cold temperature, results in a predictable increase in EE driven by a sustained rise in catecholamine and the activation of counter-regulatory mechanisms.
Celi
Francesco S
FS
Clinical Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-1613, USA. fc93a@nih.gov
Brychta
Robert J
RJ
Linderman
Joyce D
JD
Butler
Peter W
PW
Alberobello
Anna Teresa
AT
Smith
Sheila
S
Courville
Amber B
AB
Lai
Edwin W
EW
Costello
Rene
R
Skarulis
Monica C
MC
Csako
Gyorgy
G
Remaley
Alan
A
Pacak
Karel
K
Chen
Kong Y
KY
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003080:Cold Temperature; D018592:Cross-Over Studies; D004734:Energy Metabolism / Q000502:physiology*; D004777:Environment; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009638:Norepinephrine / Q000652:urine; D022722:Thermogenesis / Q000502:physiology*; D013974:Thyroxine / Q000097:blood
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D013974:Thyroxine; D006854:Hydrocortisone; D009638:Norepinephrine
Obes Rev. 2006 Aug;7(3):271-93
16866975
Crit Rev Food Sci Nutr. 2009 Nov;49(10):868-913
19960394
Am J Physiol Endocrinol Metab. 2002 May;282(5):E1077-83
11934673
Am J Physiol. 1995 Oct;269(4 Pt 1):E671-8
7485480
Circulation. 1996 Mar 1;93(5):1043-65
8598068
Br J Nutr. 1981 Mar;45(2):257-67
7213581
Br J Nutr. 2001 Feb;85(2):203-11
11242488
Clin Sci (Lond). 1999 May;96(5):483-91
10209080
J Clin Endocrinol Metab. 2010 Jan;95(1):256-62
19897683
J Clin Invest. 1980 Mar;65(3):682-9
6243675
N Engl J Med. 2009 Apr 9;360(15):1509-17
19357406
Int J Obes Relat Metab Disord. 2002 Apr;26(4):450-7
12075570
Acta Physiol Scand. 1991 Jun;142(2):201-9
1877369
Eur J Appl Physiol Occup Physiol. 1981;46(4):339-45
6266825
Endocrinology. 2000 May;141(5):1804-13
10803591
Am J Clin Nutr. 1990 Feb;51(2):241-7
2305711
Clin Chem. 1990 Apr;36(4):645-50
2136246
Clin Chem. 1986 Nov;32(11):2030-3
3096593
Am J Clin Nutr. 2000 Feb;71(2):450-7
10648257
J Clin Invest. 1986 Dec;78(6):1568-78
3782471
Am J Clin Nutr. 1998 Dec;68(6):1180-6
9846844
Eur J Clin Nutr. 2002 Apr;56(4):288-96
11965504
Endocrine. 2000 Oct;13(2):207-12
11186222
N Engl J Med. 2009 Apr 9;360(15):1500-8
19357405
J Clin Invest. 2005 Sep;115(9):2524-33
16127464
J Clin Densitom. 2009 Jan-Mar;12(1):95-102
19028125
Exp Physiol. 1999 Mar;84(2):369-77
10226177
J Clin Endocrinol Metab. 1984 May;58(5):895-903
6142901
Obesity (Silver Spring). 2010 Jun;18(6):1092-9
20360754
N Engl J Med. 2009 Feb 26;360(9):859-73
19246357
Science. 2003 Feb 7;299(5608):853-5
12574618
Curr Opin Clin Nutr Metab Care. 2002 Sep;5(5):489-93
12172471
Int J Obes Relat Metab Disord. 2001 Jul;25(7):929-34
11443488
N Engl J Med. 2009 Apr 9;360(15):1518-25
19357407