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Wildland Firefighter Health & Safety Report

Issue No. 10

Research

This section reviews project-related field studies conducted on wildland firefighters during the 2005 fire season. The studies were conducted by researchers from the University of Montana Human Performance Laboratory in cooperation with MTDC, with support from the National Wildfire Coordinating Group and the U.S. Army Research Institute for Environmental Medicine.

First Strike Rations

Liquid carbohydrate supplementation during wildland fire suppression has improved work output (Ruby and others, Medicine & Science in Sports & Exercise S219, 2004). The purpose of this study was to determine whether including snack and caffeine items (called First Strike Rations or Eat-on-Move rations) would increase work output compared to an entrée-based field ration (Meal Ready to Eat, MRE) consumed whenever firefighters felt hungry during multiple days of work. Twenty-eight wildland firefighters received each ration (First Strike Rations: 3,067 kcal, 393 g carbohydrate, 675 mg caffeine; Meal Ready to Eat: 2,841 kcal, 373 g carbohydrate, 100 mg caffeine) for 2 consecutive days separated by 1 day. Diet order was counterbalanced across participants. Eating episodes were self-reported. Mood was assessed by the Profile of Mood State questionnaire. Work output was measured by actimetry (physical activity monitoring using devices that record movements).

The number of work shift eating episodes was significantly higher with the First Strike Rations compared to the Meal Ready to Eat (8.2 vs. 7.6 episodes; p = 0.013). Salivary caffeine was higher with the First Strike Rations compared to the Meal Ready to Eat (1.6 vs. 0.7 g/mL; p = 0.01). Subjective feelings of fatigue were similar after fire suppression, but depression was modestly lower with the First Strike Rations than with the Meal Ready to Eat. Total work output during fire suppression was significantly higher (14.6 percent; p = 0.046) when consuming the First Strike Rations compared to the Meal Ready to Eat with a trend (p = 0.085) for more minutes of activity (587 vs. 567 min).

Conclusions: Delivery of energy and caffeine in a manner that promotes snacking behavior helps increase self-selected work during arduous labor.

Intermittent Feeding

Eat-on-Move rations improve actimetry scores during wildland fire suppression. 2006. Scott J. Montain, Carol J. Baker-Fulco, Philip J. Niro, Andrew Reinert, Joseph Domitrovich, and Brent C. Ruby. Paper delivered at the annual meeting of the American College of Sports Medicine.

Image of two men holding packages of food.
University of Montana researchers Brent Ruby (left)
with MREs and Steve Gaskill with First Strike Rations
for soldiers and wildland firefighters.

Our laboratory has previously demonstrated that liquid carbohydrate supplementation increases work output during wildland fire suppression (Ruby and others, Medicine & Science in Sports & Exercise S219, 2004). The purpose of this study was to determine the effect of two different eucaloric (equal or equivalent) feeding strategies on work output during wildland fire suppression. Twenty-nine type I wildland firefighters from three hotshot crews (26 males, 3 females) were studied at two wildland fires in the northwest United States during the 2005 fire season. The firefighters consumed either a sack lunch during the middle of their shift or snack foods throughout the day at 90-minute intervals after breakfast in a randomized crossover design. The total energy intake during the 12-hour shifts was eucaloric (1,534 ± 265 kcal) between days. We used a physical activity monitor (Mini Mitter, Bend, OR) to measure work output and determine activity counts. Ratings of perceived exertion were also assessed.

The total daily activity counts were significantly higher for the snack food days compared to the sack lunch days (p < 0.05). Activity counts between breakfast and lunch were significantly higher for the snack food days (p < 0.05). During the last 2 hours of the shift, activity counts were 41 percent higher on snack food days (p < 0.05). No statistically significant differences were found for perceived exertion at any time during the work shift. Satisfaction favored the snack food approach to the sack lunch approach in all categories (eight questions, p < 0.05).

Conclusions: Despite no differences in perceived exertion, the snack food group performed more overall work (8 percent) than the sack lunch group, especially during the last 2 hours of a shift (41 percent more work). Even when the total energy consumed during a work shift does not change, feeding at regular intervals increases self-selected work output during wildland fire suppression.

This project was funded by the Missoula Technology and Development Center.

Intermittent scheduled feedings increase work output during wildland fire suppression. 2006. J. Cuddy, J. Domitrovich, S. Gaskill, B. Sharkey, and B. Ruby. Paper delivered at the annual meeting of the American College of Sports Medicine.

Image of three firefighters sitting on a hillside eating.

Image of a man sitting on the ground with an assortment of food packages in front of him.
A wildland firefighter sorts
the day's food rations.