Study Objectives: Short sleep duration and sleep disturbances have been related to obesity and metabolic disruption. However, the behavioral and physiological mechanisms linking sleep and... Show moreStudy Objectives: Short sleep duration and sleep disturbances have been related to obesity and metabolic disruption. However, the behavioral and physiological mechanisms linking sleep and alterations in energy balance and metabolism are incompletely understood. In rodents, sleep regulation is closely related to appropriate brown adipose tissue (BAT) thermogenic activity, but whether the same is true in humans has remained unknown. The present work examines whether sleep duration and quality are related to BAT volume and activity (measured by F-18-FDG) and BAT radiodensity in humans.Methods: A total of 118 healthy adults (69% women, 21.9 +/- 2.2 years, body mass index: 24.9 +/- 4.7 kg/m(2)) participated in this cross-sectional study. Sleep duration and other sleep variables were measured using a wrist-worn accelerometer for seven consecutive days for 24 hours per day. The Pittsburgh Sleep Quality Index was used to assess sleep quality. All participants then underwent a personalized cold exposure to determine their BAT volume, activity, and radiodensity (a proxy of the intracellular triglyceride content), using static positron emission tomography combined with computed tomography (PET/CI) scan.Results: Neither sleep duration nor quality was associated with BAT volume or activity (the latter represented by the mean and peak standardized 18F-FDG uptake values) or radiodensity (all p >.1). The lack of association remained after adjusting the analyses for sex, date of PET/CT, and body composition.Conclusions: Although experiments in rodent models indicate a strong relationship to exist between sleep regulation and BAT function, it seems that sleep duration and quality may not be directly related to the BAT variables examined in the present work. Show less
The present study examines whether the daily rhythm of distal skin temperature (DST) is associated with brown adipose tissue (BAT) metabolism as determined by F-18-fluorodeoxyglucose (F-18-FDG)... Show moreThe present study examines whether the daily rhythm of distal skin temperature (DST) is associated with brown adipose tissue (BAT) metabolism as determined by F-18-fluorodeoxyglucose (F-18-FDG) uptake in young adults. Using a wireless thermometer (iButton) worn on the nondominant wrist, DST was measured in 77 subjects (26% male; age 22 +/- 2 years; body mass index 25.2 +/- 4.8 kg/m(2)) for 7 consecutive days. The temperatures to which they were habitually exposed over the day were also recorded. The interday stability of DST was calculated from the collected data, along with the intraday variability and relative amplitude; the mean temperature of the 5 and 10 consecutive hours with the maximum and minimum DST values, respectively; and when these hours occurred. Following exposure to cold, BAT volume and mean and peak standardized F-18-FDG uptake (SUVmean and SUVpeak) were determined for each subject via static F-18-FDG positron emission tomography/computed tomography scanning. Relative amplitude and the time at which the 10 consecutive hours of minimum DST values occurred were positively associated with BAT volume, SUVmean, and SUVpeak (p <= 0.02), whereas the mean DST of that period was inversely associated with the latter BAT variables (p <= 0.01). The interday stability and intraday variability of the DST were also associated (directly and inversely, respectively) with BAT SUVpeak (p <= 0.02 for both). All of these associations disappeared, however, when the analyses were adjusted for the ambient temperature to which the subjects were habitually exposed. Thus, the relationship between the daily rhythm of DST and BAT activity estimated by F-18-FDG uptake is masked by environmental and likely behavioral factors. Of note is that those participants exposed to the lowest ambient temperature showed 3 to 5 times more BAT volume and activity compared with subjects who were exposed to a warmer ambient temperature. Show less
![Association of wrist and ambient temperature with cold-induced brown adipose tissue and skeletal muscle [F-18]FDG uptake in young adults](/sites/all/modules/custom/islandora_solr_search/images/defaultimg.png?solr_nav%5Bid%5D=64adba28aeedc1ac8977&solr_nav%5Bpage%5D=0&solr_nav%5Boffset%5D=2)
