Accuracy of an estimated core temperature algorithm for agricultural workers

Area of Science:

• Occupational Health
• Environmental Physiology
• Biomedical Engineering

Background:

• Occupational heat exposure poses significant health risks to outdoor workers.
• Accurate monitoring of core body temperature (CBT) is essential for assessing heat stress.
• Current methods for measuring CBT can be invasive or impractical in field settings.

Purpose of the Study:

• To evaluate the accuracy of an algorithm estimating core body temperature (CBT_est) using sequential heart rate and initial CBT.
• To compare the algorithm's estimated CBT (CBT_est) with gastrointestinal temperature (CBT_gi) measured by ingestible sensors.
• To determine the algorithm's potential as a practical tool for occupational heat health research.

Main Methods:

• Data from 35 outdoor agricultural workers (pear and apple harvesters) in Washington State were analyzed.
• Core body temperature was measured using ingestible sensors (CBT_gi) and estimated using a novel algorithm (CBT_est).
• Bland Altman methods were employed to assess the agreement between CBT_est and CBT_gi across a work shift.

Main Results:

• The mean gastrointestinal core body temperature (CBT_gi) was 37.7°C (SD 0.4°C).
• The overall bias between estimated and gastrointestinal CBT was -0.14°C (±0.76°C).
• Individual biases ranged from -0.006°C to -0.75°C, indicating good agreement.

Conclusions:

• The developed algorithm provides a non-invasive method for estimating core body temperature.
• This algorithm may serve as a practical tool for research on heat stress interventions in occupational settings.
• The findings support the use of this algorithm for evaluating the effectiveness of strategies to prevent adverse heat health effects in agricultural workers.