Research

• Shift Food or Sack Lunches?
• First Strike Rations
• Hydration Systems
• Cardiovascular Risks of Incident Management Team Members
• Maintaining Firefighters' Personal Relationships

This section reviews project-related field studies conducted on wildland firefighters during the 2006 fire season. The studies were conducted by researchers and graduate students from the University of Montana Human Performance Laboratory, in cooperation with MTDC and the U.S. Army Research Institute for Environmental Medicine with support from National Wildfire Coordinating Group.

Shift Food or Sack Lunches?

This study evaluated the normal sack lunch and shift food items that supplied similar levels of energy. Sixty wildland firefighters from four interagency hotshot crews were studied at two different fires in the Northwest during the 2006 fire season. During 2 separate days, crewmembers consumed their traditional sack lunches whenever they wished during their work shift or shift food in a randomized crossover design. Shift food consisted of smaller food units (50 to 300 kcal) consumed intermittently throughout the day. The way in which the sack lunch or shift food was eaten during the day (all at once or throughout the day) was not controlled in the study. Total calories consumed were monitored and the amount of work performed was estimated using activity monitors. The firefighters were asked to rate their perceived exertion during the work shift and their satisfaction with each of the feeding strategies.

Subjective survey data show that firefighters prefer the shift food over the sack lunch for convenience, variety, satisfaction, appearance, and overall preference. While both groups received the same amount of energy (sack lunch, 1,666 kcal; shift food, 1,702 kcal), firefighters ate significantly more (358 kcal more) shift food than sack lunch food. The shift food group consumed significantly more carbohydrate (1,030 kcal total) and fat (569 kcal total) (figure 1).

Figure 1—Wildland firefighters consume a higher percentage of their food
(100 percent compared to 81 percent) when they can snack on it during
the work shift. Firefighters eating shift food consumed more fat, similar
amounts of protein (PRO), and more carbohydrate (CHO) calories
(1,030 kcal) than they were supplied (1,014 kcal). A sport drink that
had not been included in the calculations accounted for
the extra kilocalories.

The shift food cost considerably less than a sack lunch ($4.38 compared to between $9.96 and $12.77). There were no significant differences between the activity levels of either group during the 12-hour work shift, nor were there significant differences in perceived exertion.

Firefighters preferred shift food. There appeared to be no problems with shift food, and there were several advantages. Firefighters consumed more calories when they received shift food, indicating that less food was wasted and satisfaction was improved. The shift food should be a cost-effective approach to feeding wildland firefighters even after caterer costs are included. There were no negative impacts on self-selected work output throughout the work shift when firefighters received shift food, even though this study did not require firefighters to eat the shift food regularly during the work shift.

Earlier studies by our lab have shown that work output increased about 15 to 20 percent over the day, especially during the periods just before lunch and at the end of the day, when food was eaten at regular intervals throughout the work shift rather than at one sitting. Those data suggest that education is needed to encourage intermittent feeding throughout the work shift, similar to encouraging firefighters to drink fluids regularly to maintain their hydration. A combination of shift food and firefighter education should improve late morning and afternoon work output. The maintenance of blood glucose could improve immune function, worker safety, and decisionmaking. A full field trial including shift food and firefighter education needs to be conducted.

The effects of shift food on work output during arduous wildfire suppression. N. Plante, E. Lieberg, and S. Gaskill. University of Montana. Funded by MTDC.

First Strike Rations

The First Strike ration is compact and lightweight, designed to be consumed during short-term, high-intensity missions of about 3 days. It consists of 100 percent eat-on-the-move food items that are familiar and well liked. The study was conducted to determine whether First Strike rations sustain blood markers of metabolic and nutritional status as effectively as Meal, Ready to Eat rations over several days of arduous work. Eighteen active-duty military firefighters were randomly assigned to consume either one First Strike ration per day (2,864 kcal, 377 g carbohydrate, 91 g protein) or two Meal, Ready to Eat rations per day (2,620 kcal, 358 g carbohydrate, 84 g protein) for 3 consecutive days. Shift activity was measured by actimetry (Actical Physical Activity Monitor, Respironics Inc.). Food intake was assessed by a diet log and by inventorying eaten and uneaten food items. Venous blood was sampled after an overnight fast and at the end of the work shift on day 3. Differences between diet groups were assessed using mixed-model analysis of variance.

Workshift duration was similar between diet groups (First Strike ration: 691 min; Meal, Ready to Eat ration: 701 min). The percent of time performing moderate intensity work was similar over time and between groups (First Strike ration: 30 percent; Meal, Ready to Eat ration: 24 percent). While the percent of time performing light activity was sustained in the First Strike ration group (34±7 percent), it declined on day 3 in the Meal, Ready to Eat ration group (33±8 percent to 25±7 percent). Metabolic status markers as well as nutritional status markers changed over time, but there were no meaningful differences based on the type of ration.

The First Strike ration sustains metabolic and nutritional status as effectively as the Meal, Ready to Eat ration over 3 days of arduous work.

Ready to Eat during 3 days of field consumption. S. Montain, J. Cuddy, J. Domitrovich, S. Harger, L. Harris, D. Slivka, N. Yasuda, B. Ruby. U.S. Army Research Institute of Environmental Medicine (ARIEM), Natick, MA, and the University of Montana. Conducted under a memorandum of understanding with ARIEM, University of Montana, and MTDC.

Hydration Systems

Firefighters need to be well hydrated to work hard and think clearly. This study examined the use of water bottles and sipping hydration systems (with hydration reservoirs and a sipping tube) on hydration and work output during fire suppression. Twenty-seven wildland firefighters (18 male, 9 female) in a cross-over design used standard water bottles on one day and a 3-L sipping hydration system on another day. Urine samples were collected before and after the shift to determine hydration status, and subjects recorded total urine voided during the shift. Body weight was taken before and after breakfast and after the shift. Activity monitors (Minimitter, Bend, OR) were worn continually to record work output. During the work shift, subjects only consumed water from their specific hydration system. Water consumed during the work shift was monitored. At the end of the day each subject completed a subjective survey regarding the hydration system.

There were no significant differences before and after the shift between delivery systems in body weight (sipping system, 0.78 kg weight loss; water bottle, 0.80 kg weight loss), urine specific gravity, water consumed (sipping system, 3.41 L; water bottle, 3.09 L) and urine output (sipping system, 1.87 L; water bottle, 1.76 L). There was no difference in hourly work output during the work shift between delivery systems. Subjects thought the water was cooler when they used the sipping hydration system. This may have been because of the water reservoir's location in their pack.

Firefighters have used water bottles as their primary means of carrying water. Sipping hydration systems provide the opportunity to try a different hydration system. Our results demonstrated no differences in hydration status and work output between firefighters who used water bottles and those who used sipping hydration systems during wildfire suppression. Sipping hydration systems are a promising tool for use in wildland fire suppression. (For more information on hydration systems see the Field Notes section of this report, page 10.)

Hydration delivery systems for wildland firefighters. J.W. Domitrovich, S. Gaskill, B. Ruby, and B. Sharkey. The University of Montana and MTDC. Funded by MTDC.

Cardiovascular Risks of Incident Management Team Members

Incident management teams provide the organization and structure for effective wildland firefighting operations in the United States. Additionally, the teams are coordinating and managing the response to a broader category of natural and manmade disasters. The physical requirements of each position in the team depends on the job category, ranging from sedentary jobs to arduous physical work.

This study evaluated the health status and risk for coronary artery disease in a sample of incident management team members. An e-mail survey was sent to team members in Region 1 (Northern Rockies). The survey asked for self-reported data covering risk factors for coronary artery disease, including questions on physical activity and medications. The response rate was 72 percent with 6 responses that were unusable because of limited data. The responses of 66 team members were evaluated, including 52 males and 14 females. The average age was 51.2 years, with an average of 8.5 years spent serving on a team. Overall, the team members mirror national demographics in terms of cardiovascular risk factors relative to their age. They had an average of 2.6 of the following risk factors:

• 41 percent had high cholesterol values or took cholesterol medications
• 39 percent had high blood pressure or used medications for blood pressure
• 39 percent were sedentary during extended periods
• 35 percent were overweight
• 17 percent had a family history of coronary artery disease
• 3 percent were diabetic

Respondents reported above-normal levels of physical activity, but had normal cardiovascular fitness levels for their age, with 22 percent reporting musculoskeletal problems. When evaluated by their position on the team, individuals whose jobs required more physical activity reported fewer risk factors than individuals in more sedentary positions. A number of positions had just a few persons responding, but of the positions with several persons responding, individuals with a higher risk of coronary artery disease included: communications unit leaders, computer technical specialists, facilities unit leaders, incident commanders, logistics section chiefs, public safety communications, and resource unit leaders.

Low-risk positions included: division supervisors, geographic information system specialists, public information officers, and safety officers.

There were limited gender differences. When evaluated by age categories (younger than 48, 48 to 55, older than 55), individuals in the younger group had few risk factors and were more fit aerobically, while the individuals in the two older groups were not significantly different from each other.

Incident command team members whose job positions required little or no physical activity were at increasing risk of coronary artery disease compared to members whose positions required extended walking and fireline activities (table 1).

Table 1—Percent of incident command team members with risk factors for coronary artery disease.

Risk Factor	Camp Jobs (percent)	Active Jobs (percent)
Sedentary lifestyle	54	30
Overweight	46	20

While this survey represents a small sample, there are clear trends. These data suggest the need for risk-reduction interventions, both at fire camp and away from fire camp, especially for individuals whose job descriptions require little or no physical activity. Members of incident management teams represent the collective history along with much of the practical institutional knowledge about wildland firefighting. Agencies need to promote wellness and coronary artery disease risk reduction. Additional work is needed to determine successful interventions for risk reduction.

Health risks in incident management teams. S. Gaskill, B. Sharkey, and E. Lieberg, University of Montana and MTDC. Supported by MTDC.

Maintaining Firefighters' Personal Relationships

Wildland firefighting places a wide variety of demands on fire personnel. The many days away from home and the unpredictability of work schedules can complicate interpersonal relationships. Charles Palmer, a former smokejumper who is an assistant professor in the University of Montana's Department Health and Human Performance, conducted a study to understand the degree to which these factors affect firefighters.

A brief survey was administered to 249 wildland firefighters (216 males, 33 females). The firefighting experience of those surveyed ranged from less than 2 years to more than 30 years. The survey sample included a wide array of firefighters (type I and II fire crews, smokejumpers, helitack and engine personnel, dispatchers, and personnel serving in a variety of overhead positions).

Responses to the survey suggested that firefighters can have a difficult time adjusting to the demanding schedule of the job, and that the demanding schedule can present challenges to firefighters in their relationships with family and friends. Firefighters reported that maintaining intimate relationships with others is difficult, due in large part to their demanding schedule. Those who have managed to maintain intimate relationships in the face of these difficulties listed a variety of coping strategies, including:

• Educating a partner early in the relationship about the work demands
  
  
• Establishing relationships with other firefighters who better understand the time demands
  
  
• Looking for partners with independence and selfconfidence who are better able to handle the time apart
  
  
• Making the most of opportunities to build and solidify relationships during time off

Further research is needed to clarify the significance of the impacts that firefighting has on personal relationships, and to better understand the types of support that can be provided to firefighters.

Wildland firefighting and its impacts upon the personal relationships of firefighters. C. Palmer, Ed. D., University of Montana.