title: Validation of an ingestible temperature data logging and telemetry system during exercise in the heat.
abstract: Aim: Intestinal temperature telemetry systems are promising monitoring and research tools in athletes. However, the additional equipment that must be carried to continuously record temperature data limits their use to training. The purpose of this study was to assess the validity and reliability of a new gastrointestinal temperature data logging and telemetry system (e-Celsius™) during water bath experimentation and exercise trials.Materials and Methods: Temperature readings of 23 pairs of e-Celsius (TeC) and VitalSense (TVS) ingestible capsules were compared to rectal thermistor responses (Trec) at 35, 38.5 and 42°C in a water bath. Devices were also assessedin vivoduring steady-state cycling (n= 11) and intermittent running (n= 11) in hot conditions.Results: The water bath experiment showed TVSand TeCunder-reported Trec(P<0.001). This underestimation of Trecalso occurred during both cycling (mean biasvsTVS: 0.21°C, ICC: 0.84, 95% CI: 0.66-0.91; mean biasvs. TeC: 0.44°C, ICC: 0.68, 95% CI: 0.07-0.86,P<0.05) and running trials (mean biasvs. TVS: 0.15°C, ICC: 0.92, 95% CI: 0.83-0.96; mean biasvs. TeC: 0.25, ICC: 0.86, 95% CI: 0.61-0.94,P<0.05). However, calibrating the devices attenuated this difference during cycling and eliminated it during running. During recovery following cycling exercise, TeCand TVSwere significantly lower than Trecdespite calibration (P<0.01).Conclusion: These results indicate that both TeCand TVSunder-report Trecduring steady-state and intermittent exercise in the heat, with TeCpredicting Trecwith the least accuracy of the telemetry devices. It is therefore recommended to calibrate these devices at multiple temperatures prior to use.
authors.affiliation: Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Department of Life Sciences, The Centre for Human Performance, Exercise and Rehabilitation, Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, UK.
authors.forename: Gavin J S
authors.initials: GJ
authors.lastname: Travers
authors.affiliation: Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Research Institute for Sport and Exercise Science, Liverpool John Moore's University, UK.
authors.forename: David S
authors.initials: DS
authors.lastname: Nichols
authors.affiliation: Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital , Doha, Qatar.
authors.forename: Abdulaziz
authors.initials: A
authors.lastname: Farooq
authors.affiliation: Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital , Doha, Qatar.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Racinais
authors.affiliation: Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital , Doha, Qatar.
authors.forename: Julien D
authors.initials: JD
authors.lastname: Périard
keywords: calibration; core temperature; intestinal temperature; pill temperature; thermal strain