Reliability of Intestinal Temperature Using an Ingestible Telemetry Pill System During Exercise in a Hot Environment

Ruddock, Alan; Tew, Garry A.; Purvis, Alison

doi:10.1519/jsc.0b013e3182aa5dd0

Cited by 13 publications

(13 citation statements)

References 32 publications

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“…The validity of temperature measurement of each pill was verified according to recommended guidelines (Hunt & Stewart, 2008). Participants ingested the pill at the same time of day, 6 h prior to each visit (Byrne & Lim, 2007), a procedure demonstrated to provide reliable responses under similar conditions (Ruddock, Tew, & Purvis, 2014).…”

Section: Experimental Trialsmentioning

confidence: 99%

Effect of hand cooling on body temperature, cardiovascular and perceptual responses during recumbent cycling in a hot environment

Ruddock

Tew

Purvis

2016

Journal of Sports Sciences

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The purpose of this study was to quantify physiological and perceptual responses to hand immersion in water during recumbent cycling in a hot environment. Seven physically active males (body mass 79.8 ± 6.3 kg; stature 182 ± 5 cm; age 23 ± 3 years) immersed their hands in 8, 14 and 34°C water whilst cycling at an intensity (W) equivalent to 50% [Formula: see text]O for 60 min in an environmental chamber (35°C, 50% relative humidity). 8 and 14°C water attenuated an increase in body temperature, and lowered cardiorespiratory and skin blood flow demands. These effects were considered to be practically beneficial (standardised effect size > 0.20). There was a tendency for 8 and 14°C to extend exercise duration versus 34°C (>7%). Heart rate, intestinal, mean skin and mean body temperature were less in 8°C compared to 14°C; these differences were considered practically beneficial. Augmented heat loss at the palm-water surface might enable cooler blood to return to the body and limit physiological strain. These findings provide a mechanistic basis for continuous hand cooling and indicate that endurance exercise in hot environments could be improved using this method. Future research should investigate its effectiveness during cycling and running performance.

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Section: Experimental Trialsmentioning

confidence: 99%

Effect of hand cooling on body temperature, cardiovascular and perceptual responses during recumbent cycling in a hot environment

Ruddock

Tew

Purvis

2016

Journal of Sports Sciences

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“…These discrepancies have important practical implications for monitoring body core temperature in athletic and occupational settings. For instance, test re-test reliability indicates that intestinal temperature can vary by up to 0.34°C between repeat exercise trials (Ruddock et al, 2014). Therefore, detection of a meaningful difference in body core temperature during experimental trials must ensure that the combined error of ingestible sensors (which are one use only) is below this value.…”

Section: Discussionmentioning

confidence: 99%

The Systematic Bias of Ingestible Core Temperature Sensors Requires a Correction by Linear Regression

et al. 2017

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An accurate measure of core body temperature is critical for monitoring individuals, groups and teams undertaking physical activity in situations of high heat stress or prolonged cold exposure. This study examined the range in systematic bias of ingestible temperature sensors compared to a certified and traceable reference thermometer. A total of 119 ingestible temperature sensors were immersed in a circulated water bath at five water temperatures (TEMP A: 35.12 ± 0.60°C, TEMP B: 37.33 ± 0.56°C, TEMP C: 39.48 ± 0.73°C, TEMP D: 41.58 ± 0.97°C, and TEMP E: 43.47 ± 1.07°C) along with a certified traceable reference thermometer. Thirteen sensors (10.9%) demonstrated a systematic bias > ±0.1°C, of which 4 (3.3%) were > ± 0.5°C. Limits of agreement (95%) indicated that systematic bias would likely fall in the range of −0.14 to 0.26°C, highlighting that it is possible for temperatures measured between sensors to differ by more than 0.4°C. The proportion of sensors with systematic bias > ±0.1°C (10.9%) confirms that ingestible temperature sensors require correction to ensure their accuracy. An individualized linear correction achieved a mean systematic bias of 0.00°C, and limits of agreement (95%) to 0.00–0.00°C, with 100% of sensors achieving ±0.1°C accuracy. Alternatively, a generalized linear function (Corrected Temperature (°C) = 1.00375 × Sensor Temperature (°C) − 0.205549), produced as the average slope and intercept of a sub-set of 51 sensors and excluding sensors with accuracy outside ±0.5°C, reduced the systematic bias to < ±0.1°C in 98.4% of the remaining sensors (n = 64). In conclusion, these data show that using an uncalibrated ingestible temperature sensor may provide inaccurate data that still appears to be statistically, physiologically, and clinically meaningful. Correction of sensor temperature to a reference thermometer by linear function eliminates this systematic bias (individualized functions) or ensures systematic bias is within ±0.1°C in 98% of the sensors (generalized function).

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“…Six hours before the experimental trial participants ingested a telemetry pill to assess intestinal temperature (CorTemp, HQinc, USA). This procedure has been demonstrated to provide reliable data under similar conditions [243]. The validity of temperature measurement of each pill was confirmed according to recommended guidelines [254] (mean r 2 = 0.99).…”

Section: Experimental Trialsmentioning

confidence: 66%

“…Such responses (e.g. core temperature) are typically reliable [63,64,243] and enable valid comparisons between interventions. Bongers et al [7] did not discriminate between fixed intensity exercise or self-paced performance and it was not the aim of Tyler et al [6] to do so, but both studies reported thermophysiological responses.…”

Section: Discussionmentioning

confidence: 99%

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Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

Ruddock¹

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Reliability of Intestinal Temperature Using an Ingestible Telemetry Pill System During Exercise in a Hot Environment

Cited by 13 publications

References 32 publications

Effect of hand cooling on body temperature, cardiovascular and perceptual responses during recumbent cycling in a hot environment

Effect of hand cooling on body temperature, cardiovascular and perceptual responses during recumbent cycling in a hot environment

The Systematic Bias of Ingestible Core Temperature Sensors Requires a Correction by Linear Regression

Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

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