PURPOSE: The purpose of this study was to assess if core temperature thresholds for exercise ventilation differ between sites of core temperature measurement during an incremental exercise test from rest to the point of exhaustion. It was hypothesized that the core temperature threshold for the ventilatory equivalent for oxygen (VE/VO2),measured with ingestible pill temperature, would not be different from the oesophageal temperature and tympanic membrane temperature thresholds for VE/VO2. METHODS: Four females volunteered for this study that was approved by the SFU Office of Research Ethics. Two of the female volunteers were amenorrheic and the other two were in follicular phase of their menstrual cycles. The results were then compared to four males VE/VO2 oesophageal (TOES) and tympanic membrane (TTY) temperature thresholds from a published study. Each volunteer after a 24 h reflection period, signed a medical history form, a PAR-Q, as well as gave their signed informed consent. Core temperature thresholds for exercise ventilation were assessed with an ingestible pill temperature (TPILL) sensor, with a TOES probe and with TTY probe. Minute ventilation (VE) and volume of consumed oxygen (VO2) were quantified by indirect calorimetry. Vieth threshold software was employed to determine the core temperature thresholds for VE/VO2. An unpaired, two-tailed t-test was used to compare the core temperature thresholds for exercise ventilation. The P value was set at 0.05. RESULTS: The TPILL threshold for VE/VO2 of 37.1±0.4°C(mean±SD) showed a trend (p=0.06) to be lower than the TES threshold for VE/VO2 of 37.5±0.2°C. No difference was evident between TPILL threshold and TTY threshold of 37.03±0.2°C for VE/VO2. In conclusion, these preliminary results show a trend towards a lower core temperature threshold for exercise ventilationwhen measured in the gastrointestinal tract as compared to an esophageal temperature threshold for exercise ventilation.

Supported by lululemon athletica ™, Mitacs Accelerate, NSERC Engage and CFI

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