Author
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MOON, JON - BAYLOR COLL OF MEDICINE |
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BUTTE, NANCY - BAYLOR COLL OF MEDICINE |
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Submitted to: Journal of Applied Physiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/6/1996 Publication Date: N/A Citation: N/A Interpretive Summary: Studies have shown that heart rate and physical activity records can be used to estimate human beings' rates of metabolism. Using small electronic monitors to record heart rate and physical activity is cheaper and easier than other methods, but these monitors did not work well as a way of predicting oxygen consumption and carbon dioxide production rates until recent design improvements. We decided to see how well these monitors, wor on the body to measure heart rate and physical activity, could measure oxygen consumption and carbon dioxide production compared against measurements taken in a room calorimeter, which is an enclosed living area in a clinical setting capable of accurately measuring oxygen use, output and other bodily activities associated with energy expenditure. Our results indicate that combined heart rate and physical activity (recorded electronically) measured oxygen consumption and carbon dioxide production as well as the best available alternative methods. MANUSCRIPT FOR JOURNAL _X__ (ABSTRACT ___ INTERPRETIVE SUMMARY _X__) Technical Abstract: Oxygen consumption (VO2) and carbon dioxide production (VCO2) rates were measured with electronically recorded heart rate (HR) and physical activity (PA). Mean daily VO2 and VCO2 measurements by HR and PA were validated in twenty healthy adults (female: n = 10) with fast-response, room calorimeters. Thirteen linear and nonlinear functions of HR alone and HR combined with PA were tested as models of 24-h VO2 and VCO2. Mean sleep VO and VCO2 were similar to measured basal metabolic rates and were accurately estimated from HR alone [respective mean (SD) errors were -0.2 (0.8)% and -0.4 (0.6)%]. The range of prediction errors for 24-h VO2 and VCO2 was smallest for a model that used PA to assign HR for each min to separate active and inactive curves [VO2: -3.3 (3.5) %, VCO2: -4.6 (3) %]. There were no significant correlations between VO2 or VCO2 prediction errors and subject age, weight, sex, fat mass or fitness (estimated peak VO2). HR and PA also were recorded for 3 free-living days. Free-living VO2 and VCO2 wer 5.6 (0.9) mL/min/kg and 4.7 (0.8) mL/min/kg, respectively. Combined HR and PA measured 24-h VO2 and VCO2 with a precision similar to the best available alternative methods, such as doubly-labeled water. Key words: energy expenditure, humans, respiration calorimeter, electronic monitor |
