Assessing rectal temperature with a novel non-invasive sensor.

Area of Science:

• Exercise Physiology
• Environmental Health
• Biomedical Engineering

Background:

• Intense physical activity in hot environments increases physiological thermal strain, potentially leading to heat exhaustion and heatstroke.
• Continuous monitoring of core body temperature (Tc) is vital for managing heat-related illnesses.
• The Tcore sensor, using dual-sensor heat flux technology, is a new device for Tc measurement in controlled settings.

Purpose of the Study:

• To evaluate the accuracy of the Tcore sensor for monitoring rectal temperature (Tre), a surrogate for Tc, under exercise-heat stress conditions.
• To develop and validate new algorithms for the Tcore sensor to improve Tre estimation from forehead and wrist measurements.

Main Methods:

• Thirteen healthy males performed 90-minute moderate exercise protocols under controlled hot/dry and hot/wet conditions.
• Tcore sensors were placed on the forehead and wrist, with continuous Tre recorded via a rectal thermistor.
• New MATLAB algorithms were developed and validated using cross-validation and Bland-Altman analysis on approximately 150,000 data points.

Main Results:

• The original Tcore algorithm was inadequate; new models for forehead and wrist were developed.
• Mean absolute errors for the new models were 0.20 ± 0.16 °C (forehead) and 0.27 ± 0.20 °C (wrist).
• Forehead model achieved 95% agreement within ±0.5 °C of Tre, while the wrist model achieved 86% agreement within the same range.

Conclusions:

• Developed Tcore sensor algorithms demonstrate feasibility for assessing Tre under exercise-heat stress.
• The Tcore sensor, particularly on the wrist, shows potential for practical field use in monitoring body temperature.
• Accurate core body temperature monitoring can aid in preventing heat-related illnesses in physically active individuals in hot climates.