ABSTRACT
The aim of this study was to evaluate the carriage of a portable gas analyser during prolonged treadmill exercise at a variety of speeds. Ten male participants completed six trials at different speeds (4, 8 and 12 km h(- 1)) for 40 min whilst wearing the analyser (P) or where the analyser was externally supported (L). Throughout each trial, respiratory gases, heart rate (HR), perceptions of effort and energy expenditure (EE) were measured. Significantly higher EE occurred during P12 (p = 0.01) than during L12 (855.3 ± 104.3; CI = 780.7-930.0 and 801.5 ± 82.2 kcal; CI = 742.7-860.3 kcal, respectively), but not at the other speeds; despite this, perceptions of effort and HR responses were unaffected. This additional EE is likely caused by alterations to posture which increase oxygen demand. The use of such systems is unlikely to affect low-intensity tasks, but researchers should use caution when interpreting data, particularly when exercise duration exceeds 30 min and laboratory-based analysers should be used where possible.
Subject(s)
Energy Metabolism , Exercise Test/instrumentation , Lifting , Monitoring, Physiologic/instrumentation , Adult , Breath Tests , Heart Rate , Humans , Male , Oxygen Consumption , Physical Exertion , Running/physiology , Walking/physiologyABSTRACT
This study aimed to assess the effect of portable gas analysis system carriage on energy expenditure (EE) during incremental treadmill running. Eight males (Mean ± SD) age 25.0 ± 9.47 y, body mass 78.5 ± 8.39 kg, completed an experimental trial (PT) during which they wore the system in a chest harness and a control trial (CT) when the system was externally supported. Each protocol consisted of 4 min stages at speeds of 0, 4, 7, 10, 12, 14 km h(-1). Increments continued until volitional exhaustion. The EE was greater (3.95 and 7.02% at 7 and 14 km h(-1) respectively) during PT (p < 0.05) but no significant differences were observed during standing, walking or VO(2max.) (4.10 ± 0.53, and 4.28 ± 0.75 l min(-1) for CT and PT respectively), HR or RPE. Portable gas analysis systems therefore only increase EE when running sub-maximally, but VO(2max) is unaffected, suggesting that using portable gas analysis systems in field-based situations is appropriate for maximal aerobic capacity measurement, but the effects of prolonged use on EE remains unclear.
