Fifty-five male and female subjects volunteered to participate in the DLW assessments to estimate their TEE. Six subjects were excluded from this report because of anomalies in their 2H and 18O decay curves. An additional three subjects were excluded because of missing HR logs. The final sample of 46 subjects included 16 middle-aged men (mean age 51.4 years), 14 middle-aged women (mean Selleckchem MG 132 age 49.9 years) and 16 young women (mean age 19.1 years). This study was conducted in accordance with the Helsinki Declaration, and was approved by the ethics committee of the Central Finland Health Care District. Written informed consent was obtained from all subjects
prior to the assessments. All measurements were performed after an overnight fast. The participants were weighed while wearing light clothes and without shoes. The weight was determined within 0.1 kg for each subject using an electronic scale calibrated before each measurement session. The height was determined using a fixed wall-scale measuring device to the nearest 0.1 cm. The body mass index (BMI, kg/m2) was calculated as weight/height2.
The TEE (kcal/day) was measured by the DLW method as previously described.23 Briefly, on day 1, the first urine sample was collected from each participant in the morning before the intake of a body weight-dependent (1 g per kg of body weight) dose of DLW (pre-mixed aliquots of 100 g of 10% 18O enriched water with 8 g of 99.9% 2H enriched Selleckchem Ribociclib water). Four to six hours after until consuming the DLW, the subjects provided a second urine sample. On day 14, the first sample was obtained in the morning after an overnight fasting, and the second sample was collected 4–6 h afterwards. The urine samples were stored at −80 °C until analysis. The samples were analyzed in triplicate for the 2H and 18O isotope ratio by mass spectrometry (Metabolic Solutions
Inc., Merrimack, NH, USA) at the University of Alabama, Birmingham, USA. The TEE was calculated using the validated described by Schoeller et al.24 and 25 The subjects wore an HR monitor (Body Guard, FirstBeat Oy, Jyväskylä, Finland) for 24 h before the REE measurement. The device was attached directly to the skin at three points, eliminating the need to wear a belt around the body and thus minimizing skin contact. The recorded 24-h HR data were then downloaded to a computer. The TEE was estimated using newly-developed software (MoveSense HRAnalyzer 2011a, RC1) provided by Suunto Company (Vantaa, Finland). The algorithm used in this software for the TEE estimation is based on HR reserve, taking into account age, gender and BMI. The REE (kcal/day) was assessed by respiratory gas exchange analysis (GEA) using a ventilated-hood system (VIASYS Healthcare, Yorba Linda, CA, USA). Calibration of the GEA was carried out before each measurement according to the manufacturer’s instructions.