Minimal changes in environmental temperature result in a significant increase in energy expenditure and changes in the hormonal homeostasis in healthy adults.
Eur J Endocrinol
; 163(6): 863-72, 2010 Dec.
Article
em En
| MEDLINE
| ID: mdl-20826525
ABSTRACT
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.DESIGN:
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 19â°C with simultaneous measurement of spontaneous movements and hormonal axes.RESULTS:
Exposure to 19â°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 19â°C.CONCLUSIONS:
Our observations indicate that exposure to 19â°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.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Temperatura Baixa
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Termogênese
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Metabolismo Energético
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article