The effect of cold acclimation on brown adipose tissue.

The volunteers will undergo two PET/CT-scans, in which cold-induced BAT activity will be measured before and after a cold acclimation period of 10 days. To investigate the role of the skeletal muscle mitochondrial uncoupling and BRITE cell recruitment a muscle and fat biopsy sample will be taken prior to the acclimation period and afterwards. Finally, body composition will be determined with a DXA-scan, and skin perfusion and relevant body temperatures will be measured as well.

Chronic cold exposure will increase:

1. Basal metabolism and facultative thermogenesis;

2. Brown adipose tissue activity and volume;

3. Skeletal muscle mitochondrial uncoupling and result in BRITE cell recruitment.

Participation will take approximately 70 hours.

The volunteers will undergo two PET/CT-scans, in which cold-induced BAT activity will be measured before and after a cold acclimation period of 10 days. To investigate the role of the skeletal muscle mitochondrial uncoupling and BRITE cell recruitment a muscle and fat biopsy sample will be taken prior to the acclimation period and afterwards. Finally, body composition will be determined with a DXA-scan, and skin perfusion and relevant body temperatures will be measured as well.

Cold acclimation is achieved by exposure to an environmental temperature of 16 degrees (cold room) for 10 consecutive days. The first day the subjects will remain in this cold room for 2 hours, the second day for 4 hours and days 3-10 for 6 consecutive hours. The subjects are dressed in t-shirt, shorts and flip flops. For these 6 hours, the subjects are instructed to refrain from physical activity as much as possible. Watching TV and working on a computer are activities that can be done.