Energy Expenditure Measure By Portable Accelerometer During A High Altitude Trekking

Abstract: In the last years an ever increasing number of people participate in pleasure or work activities at high altitude. In this framework, the assessment of individual energy expenditure during ascent would be of great interest for adapting physical strain and personalizing food intake and equipment. However, environmental conditions prevent from obtaining a simple measure of energy expenditure by traditional methods. Recently, accelerometers have been introduced in clinical practice and scientific research, allowing to measure subjects energy expenditure during daily activities and different physical exercises. PURPOSE: aim of this study was to measure the total and single stage energy expenditure of healthy adults, during a trekking at high altitude, using an arm accelerometer. METHODS: fourteen healthy subjects (mean age 29.8\ub112.3 years, range 22-59 years) wore anAccelerometer SenseWear Pro Armband (Body Media, Inc., USA) during a 7-day trekking from Lukla airport (2851m) to the Pyramid Laboratory (5050 m, Nepal), for a total ascent of 2199 meters, divided into 5 stages. Daily subjects physical activity have been recorded and relative energy expenditure calculated. RESULTS: total energy expenditure related to physical activity ranged from 5987.4 and 10744.8 kcal (from 89.5 to 141.4 kcal/kg). Per kilogram average energy expenditure for the entire trekking was 116.8\ub114.8kcal/kg (mean\ub1SD), while the average energy expenditure for each 100 meters of ascent was 5.15\ub11.06 kcal/kg. Evaluating single stages, inter-individual per kilogram variability ranged from 16.3\ub13.7 and 29.2\ub14.8kcal/kg (from 16.1 to 26.5% of the single stage total energy expenditure). CONCLUSION: Our study confirms that the portable Accelerometer SenseWear Pro Armband is a useful and practical tool to assess energy expenditure during a trekking at high altitude. However, despite a similar track, we demonstrate a moderate inter-individual variability of measured energy expenditure. This variability could possibly be ascribed to different arm movements during walking and to different body composition