Introduction:​ The seasonal profession of wildland fire fighting in Canada requires individuals to work in harsh environmental conditions that are physically demanding. The purpose of this study was to use novel technologies to evaluate the physiological demands and nutritional practices of Canadian FireRangers during fire deployments.

Methods:​ Participants (n = 21) from a northern Ontario Fire Base volunteered for this study and data collection occurred during the 2014 fire season and included Initial Attack (IA), Project Fire (P), and Fire Base (B) deployments. Deployment-specific energy demands and physiological responses were measured using heart-rate variability (HRV) monitoring devices (Zephyr BioHarness3 units). Food consumption behaviour and nutrient quantity and quality were captured using audio-video food logs on iPod Touches and analyzed by NutriBase Pro 11 software.

Results:​ Insufficient kilocalories were consumed relative to expenditure for all deployment types. Average daily kilocalories consumed:​ IA:​ 3758 (80% consumption rate);​ P:​ 2945±888.8;​ B:​ 2433±570.8. Average daily kilocalorie expenditure:​ IA:​ 4538±106.3;​ P:​ 4012±1164.8;​ B:​ 2842±649.9. The Average Macronutrient Distribution Range (AMDR) for protein was acceptable:​ 22–25% (across deployment types). Whereas the AMDR for fat and carbohydrates were high:​ 40–50%;​ and low:​ 27–37% respectively, across deployment types.

Conclusions:​ This study is the first to use the described methodology to simultaneously evaluate energy expenditures and nutritional practices in an occupational setting. The results support the use of HRV monitoring and video-food capture, in occupational field settings, to assess job demands. FireRangers expended the most energy during IA, and the least during B deployments. These results indicate the need to develop strategies centered on maintaining physical fitness and improving food practices.