Total energy expenditure during arduous wildfire suppression

Area of Science:

• Physiology
• Environmental Health
• Occupational Safety

Background:

• Wildland firefighting is physically demanding, requiring substantial energy.
• Accurate measurement of total energy expenditure (TEE) is crucial for understanding firefighter health and performance.
• The doubly labeled water (DLW) method offers a non-invasive approach to assess TEE.

Purpose of the Study:

• To determine the total energy expenditure (TEE) of wildland firefighters.
• To evaluate the suitability of the doubly labeled water (DLW) methodology for measuring TEE during wildfire suppression activities.
• To assess energy expenditure across diverse geographical locations during fire suppression.

Main Methods:

• Seventeen wildland firefighters (8 men, 9 women) participated in the study.
• Subjects received an oral dose of deuterium oxide (2H2O) and oxygen-18 water (H218O).
• Urine samples were collected daily for 5 days to calculate TEE using the DLW method, with adjustments for background enrichment and water turnover.

Main Results:

• Mean TEE was consistently high, averaging 17.4 MJ/d for days 1-3 and 17.5 MJ/d for days 4-5.
• Energy expenditure associated with physical activity (EEA) was also substantial, recorded as 8.8 MJ/d (days 1-3) and 8.9 MJ/d (days 4-5).
• The DLW method proved effective in measuring TEE during dynamic field operations.

Conclusions:

• Wildland firefighters demonstrate a consistently high daily energy expenditure.
• The DLW methodology is appropriate for measuring TEE in unpredictable field settings.
• Adjustments for background enrichment and elevated water turnover are essential for accurate DLW measurements in this population.