Restoring normal thyroid function may reverse cold-induced thermogenesis, say researchers writing in the journal Thyroid.
Cold temperature-induced thermogenesis, or shivering, can afflict adults with hypothyroidism who may be particularly sensitive to the cold. They may also suffer from unintended weight gain, which may indicate changes in the body's energy expenditure in response to cold temperatures.
This was a study of 33 patients with subclinical or overt hypothyroidism who were scheduled to receive hormone therapy. The primary endpoint was the change in cold-induced thermogenesis specifically between the hypothyroid and euthyroid state.
Energy expenditure during warm conditions increased from an average of 1,330 kcal every 24 hours during a hypothyroid state to an average of 1,442 kcal per 24 hours during a euthyroid state. But in cold temperatures, the energy exposure went form 1,399 kcal per 24 hours to 1,610 kcal per 24 hours.
The median cold-induced thermogenesis was 55 kcal per 24 hours at baseline, but after hormone therapy it increased by 102 percent.
“This study shows that even moderate levels of hypothyroidism reduce cold-induced thermogenesis and that sufficient replacement of thyroid hormones restores cold-induced thermogenesis. This effect might be due to reduced recruitment of brown adipocytes during the cold season and warrants further investigation,” wrote researchers who were led by Matthias Johannes Betz, M.D., University Hospital Basel in Switzerland.
Claudia Irene Maushart, Rahel Loeliger, Gani Gashi, Mirjam Christ-Crain, and Matthias Johannes Betz. "Resolution of Hypothyroidism Restores Cold-Induced Thermogenesis in Humans," Thyroid. Published online Apriil 9, 2019. https://doi.org/10.1089/thy.2018.0436