0251-2815-MTDC: Wildland Firefighter Health & Safety Report No. 5

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Wildland Firefighter Health & Safety Report

Spring 2002 MTDC No. 5

Featured Topic

Work and Fatigue in Wildland Firefighting
Energy Balance and Nutritional Deficiencies
Environmental Stresses
Shift Length and Sleep Duration
Assignment Length
Recovery Between Assignments
Guidelines for Monitoring and Enhancing Recovery from Accumulated Fatigue
Avoiding Accumulated Fatigue
Additional Fatigue Countermeasures
Related Topics

Work and Fatigue in Wildland Firefighting
Steven Gaskill, Ph.D.

In 1980 and 1989 the Missoula Technology and Development Center reviewed studies related to fatigue during extended firefighting operations. Since then, MTDC and others have completed additional studies. This report summarizes recent recommendations from laboratory and field studies.

Definitions:

Fatigue—A sense of tiredness, either mental or physical, brought on by stress (lack of sleep, physical work, nutritional inadequacies, or mental stresses). Fatigue following work or sleep deprivation is a normal state and can be reversed with adequate recovery or rest.

Accumulated (Chronic) Fatigue—Fatigue from which normal rest does not produce recovery. Accumulated fatigue is often caused by extended periods of stress with inadequate recovery periods, resulting in decreased productivity, compromised immune function, and reduced alertness.

Fatigued workers perform poorly and behave carelessly, tolerate greater errors, and become inattentive. They display decreased motivation, increased irritability and depression, and low morale. Accumulated fatigue is more persistent, producing a wider array of effects on performance, health, and morale than ordinary fatigue. Accumulated fatigue requires longer recovery periods than ordinary fatigue.

Energy Balance and Nutritional Deficiencies

The total calories eaten by firefighters need to match the total calories expended over an entire duty cycle and, ideally, over an entire season of firefighting. This balance can generally be monitored by body weight. However, the type of food that is eaten and the time that the food is eaten may have a dramatic effect on the body's ability to recover from physical stress.

Recommendations for Maintaining Energy Balance

Body weight should be maintained over the course of a work assignment. Daily fluctuations of 1 to 3 pounds are normal, due to water loss. Water loss should be replenished before sleeping each night. Loss of weight because of dehydration or loss of lean body mass is a sign of fatigue and decreased work productivity. Sustained weight losses of more than 1 to 2 pounds per week have been shown to decrease immune function.
The wildland firefighter's diet should include at least 60 percent of calories from carbohydrates with less than 30 percent of calories from fats. The diet should include about 1.2 to 1.6 grams of protein for each kilogram (2.2 pounds) of body weight. This represents 84 to 112 grams of protein per day for a 70-kilogram (154-pound) individual and 120 to 160 grams of protein per day for a 100-kilogram (220-pound) individual (an ounce is 28.4 grams, about 70 percent of lean meat is protein). This recommendation is based on studies of individuals engaged in arduous aerobic or muscular fitness training.
Blood glucose and muscle glycogen (carbohydrate stored in the muscle) need to be maintained or spared during extended, arduous work to maintain immune function, reduce upper respiratory tract infections (URTI), and promote work productivity, cognitive function, and safety. Supplemental foods and fluids containing carbohydrate need to be consumed regularly during the work day.
Muscle glycogen levels need to be restored between work shifts through normal diet and also by carbohydrate intake during the "window of opportunity" when muscle glycogen is most easily restored. This window of opportunity is within 15 to 45 minutes after a work shift has been completed. Individuals should eat high-glycemic (quickly absorbed) carbohydrates during the window of opportunity. Crews might need to have supplemental food available between the end of the shift and the next meal. This food may need to be available when crews are being transported (or when they are waiting to be transported) or during any situation when they will not receive a meal within 45 minutes after they have finished their work shift.
Crewmembers must maintain hydration at the beginning of and during the work shift. Crew leaders need to watch for crewmembers who may not be carrying or consuming enough water, especially when crews are working in hot, dry conditions.

Environmental Stresses

Environmental stresses add to the total stress of a wildland firefighter's duties and should be considered when crew leaders evaluate situations that may increase accumulated fatigue. Increases in altitude, heat, humidity, and smoke increase the risk of fatigue. In addition, rough, steep terrain and dangers such as rolling rocks and snags increase physical and mental stress, leading to a high level of fatigue. More rest may be required to recover adequately before the next work shift when crews are working in such conditions.

Recommendations for Acclimatization to the Environment

Acclimatization periods are necessary for extended work at elevations higher than 6,000 feet or when crews are working in areas with high temperature or humidity. Guidelines should be developed to help managers decide when acclimatization periods are necessary.
Work shifts should be shortened with reduced workloads for 2 to 3 days while workers acclimatize to heat stress.
Acclimatization to altitude depends on elevation, but a general guideline would be to reduce the duration and intensity of the work shift for 1 day for each 1,000 feet in elevation above 6,000 feet. Individuals differ in their response to environmental stress. Crew leaders need to watch each crewmember for signs of heat stress or altitude-related problems.

Shift Length and Sleep Duration

The recommendations of the 1989 Wildland Firefighter Work/Rest Cycles Review are still valid. Crew leaders should adhere to the 2:1 work/rest requirement (for each 2 hours of duty time—portal to portal—crewmembers should receive 1 hour of rest or sleep). Longer shift lengths require additional sleep. These data are supported by research for shift lengths up to 24 hours.

Recommendations on Shift Length and Sleep Duration

The current two-shift system (12 to 14 hours) is the preferred alternative, providing that firefighters are provided 1 hour of sleep or rest for every 2 hours worked.
Most rested individuals can tolerate up to a 24-hour work shift without substantial loss of cognitive or physical performance, so long as adequate recovery is given between shifts.
Long work shifts (such as shifts over 20 hours) may impair recovery of the immune system (see Research, page 7).
Cognitive function is best maintained if the task is interesting or demanding. Changing tasks improves performance during a long shift.
Crew leaders need to be especially careful that they get enough rest. Long shifts and lack of sleep impair cognitive function more quickly than they impair physical productivity.

Assignment Length

Many studies of extended operations have been conducted during military training exercises. Wildland firefighters worked 21-day assignments until the 2000 fire season. Athletes perform prolonged strenuous activities for periods of up to 21 days (such as during the Tour de France bicycle race). Research studies and real-world experience agree that workers or athletes with adequate fitness, nutrition, motivation, and rest can maintain performance for as long as 21 days (for more on assignment length see Risk Management).

Recovery Between Assignments

A large number of factors need to be evaluated to meet the goal of having crewmembers and leaders begin an assignment in a rested state. No data have been collected on wildland firefighters to evaluate whether the 2-day break between assignments is adequate, or whether the crewmembers and leaders are able to recover adequately during the 2-day break. A related question about rest and recovery is the state of fatigue when crews begin an assignment. Do transport or other logistical factors result in a lack of sleep? A change in time zones or transport to an extreme environment (high altitude or increased heat and humidity) could increase the potential for stress and fatigue.

Recommendations for Evaluating Fatigue at the Start of Arduous Work

In all situations, the crew leaders should evaluate the need for additional sleep and rest, or the need to acclimatize before beginning an arduous shift.
Further research is needed to evaluate the effects of various stressors on the ability to recover between assignments.

Guidelines for Monitoring and Enhancing Recovery from Accumulated Fatigue

This section summarizes basic guidelines crew leaders can use to identify signs of accumulated fatigue. Visible symptoms that an individual is not recovering adequately from daily stresses vary and depend on the individual. Crew leaders should pay attention to individuals who complain about or manifest two or more of the following signs, especially when the crew has been exposed to situations that can increase the risk of accumulated fatigue. In addition, the field tests described below may prove helpful in situations where leaders expect fatigue to be excessive.

Many of the symptoms of accumulated fatigue, when viewed independently of other symptoms, may not indicate accumulated fatigue. When multiple symptoms occur simultaneously, crew leaders should take appropriate actions to reduce stress and enhance recovery for the crewmembers who are affected, or for the entire crew.

The symptoms of accumulated fatigue include:

Loss of body weight
Decreased appetite
An increase in resting heart rate
An increase in submaximal heart rate at a fixed work load
Perception that standard work tasks are more difficult
Small (to large) losses in coordination and the ability to do tasks requiring coordination
Muscle soreness that lasts more than 24 hours
Increase in upper respiratory tract infections such as colds or flu
Decreased cognitive function
Constipation or diarrhea
A change in moods that may include irritability or decreased motivation or desire

Crew leaders should know and apply measures to enhance recovery from accumulated fatigue. The basic measures include:

Increased sleep in an environment conducive to sleep
Reduced duration and frequency of physical work (possible change of duty the following day)
Adequate supplemental nutrition and fluids during and immediately after physical work
A high carbohydrate diet
Monitoring the individuals for recovery

Avoiding Accumulated Fatigue

All of the symptoms listed above, except the resting and submaximal heart rates, appear only after accumulated fatigue is evident. Of the easily measured field symptoms, only the heart rate measures seem to give some advance warning that an individual is approaching a state of accumulated fatigue. When a crew leader recognizes symptoms in crewmembers, the leader should take steps to enhance recovery.

When crews are placed in environments that might increase their risk for accumulated fatigue, when crews are starting an assignment in a fatigued state, or when increased mental and physical stresses are anticipated, crew leaders may choose to monitor individuals. This monitoring is in addition to attention paid to normal symptoms of accumulated stress. Monitoring crewmembers in the field may require some equipment and take a short period of time each day. Current suggestions include two tests that may also be used to evaluate when workers have recovered from accumulated fatigue.

Recommendations for Monitoring Accumulated Fatigue

Compare daily body weight to baseline weights. During stressful assignments, daily body weight should be recorded when possible each morning before any food or fluids are consumed. This requires that data be maintained over the fire season, including the baseline weight of individuals in a rested state. Daily fluctuations are expected based on dehydration and fluid loss that can be replaced during meals. Consistent patterns of weight loss suggest environments and work that do not allow adequate recovery, or reflect inadequate nutritional intake. Generally, supplemental carbohydrate intake and maintenance of fluids should be adequate to enhance recovery for fit individuals.
Monitor morning heart rate response to a standard 4-minute test (requiring 1 minute of easy bench stepping and 3 minutes of rest) for early signs of fatigue and impaired recovery. This fatigue test was evaluated during the summer of 2001 and compared to clinical measurements of immune function. Athletes have used morning resting and submaximal heart rate responses to monitor overtraining. The fatigue test might be appropriate for crews in "at-risk" situations or when accumulated fatigue might be expected. Using this test requires taking baseline measurements and maintaining data on individuals over a period of time to establish patterns (see Field Notes, page 12).

For these tests to be practical in a fire camp, the medical tent would need to include a scale and an 8-inch bench. Another alternative would be for type 1 crews to carry a scale and bench.

Additional Fatigue Countermeasures

Fatigue countermeasures have been studied in military populations and endurance athletes. Although many questions remain to be answered, work cycling is one area of interest that may yield positive benefits for wildland firefighters.

Work Cycling—Athletes and coaches have long understood that one of the most effective methods to counteract overtraining (accumulated fatigue) is to vary the training in both intensity and duration so that days of arduous activity are interspersed with less stressful days. This concept allows athletes to avoid illness and accumulated fatigue by scheduling time to recover between hard work periods. The result is reduced time lost to illness, improved alertness, increased total work, and higher productivity. The same principles should apply to wildland firefighters if stressful days are interspersed with less stressful days. This might be done for an entire crew or just for certain individuals. Most physically fit individuals can sustain 1 to 2 days of very arduous work, if they have a less stressful period (1 to 2 days) for recovery. Recovery days do not require inactivity, but do require a change of duty, generally to a duty with less total stress. Little is known about duty cycling for wildland firefighters, but further study might be beneficial. Recommendations for ways to vary the daily intensity and duration of arduous duty should be developed.

Fitness—Physical fitness is another known factor in accumulated fatigue in athletes and workers. When team members are asked to do similar training for extended periods, athletes who are physically fit generally exhibit fewer symptoms of accumulated stress than do individuals who are less fit. Research during the summer of 2001 with two type 1 crews suggested that the fit workers did more work (both in absolute terms and adjusted for body weight) and experienced less fatigue.

Fitness Recommendations for Wildland Firefighters

Aerobic and muscular endurance training before the fire season that is maintained throughout the season would benefit firefighters who routinely work in situations requiring multiple extended arduous work shifts with moderate to high energy output. Fitness standards that are higher than the pack test (walking 3 miles with a 45-pound pack in 45 minutes) should be considered. A fitness training manual should be available to type 1 crews.
Individuals who have been relatively sedentary but who wish to take the pack test should begin a training program gradually and slowly build up to the work capacity required for a wildland firefighter. The pack test should be considered a minimum fitness require-ment. Individuals who will be working on the fireline should be encouraged to improve their aerobic (endurance) and muscular fitness.
The onset of fatigue as a result of work depends on the individual and is related to many factors. Methods to monitor fatigue within fire crews need to be developed to determine when individuals or entire crews need time to recover.




T&D > T&D Pubs > Wildland Firefighter Health & Safety Reports > 0251-2815-MTDC: Wildland Firefighter Health & Safety Report No. 5 Table of Contents Back \| Next \| Cover Page Spring 2002 MTDC No. 5 Featured Topic Work and Fatigue in Wildland Firefighting Energy Balance and Nutritional Deficiencies Environmental Stresses Shift Length and Sleep Duration Assignment Length Recovery Between Assignments Guidelines for Monitoring and Enhancing Recovery from Accumulated Fatigue Avoiding Accumulated Fatigue Additional Fatigue Countermeasures Related Topics Work and Fatigue in Wildland Firefighting Steven Gaskill, Ph.D. In 1980 and 1989 the Missoula Technology and Development Center reviewed studies related to fatigue during extended firefighting operations. Since then, MTDC and others have completed additional studies. This report summarizes recent recommendations from laboratory and field studies. Definitions: Fatigue—A sense of tiredness, either mental or physical, brought on by stress (lack of sleep, physical work, nutritional inadequacies, or mental stresses). Fatigue following work or sleep deprivation is a normal state and can be reversed with adequate recovery or rest. Accumulated (Chronic) Fatigue—Fatigue from which normal rest does not produce recovery. Accumulated fatigue is often caused by extended periods of stress with inadequate recovery periods, resulting in decreased productivity, compromised immune function, and reduced alertness. Fatigued workers perform poorly and behave carelessly, tolerate greater errors, and become inattentive. They display decreased motivation, increased irritability and depression, and low morale. Accumulated fatigue is more persistent, producing a wider array of effects on performance, health, and morale than ordinary fatigue. Accumulated fatigue requires longer recovery periods than ordinary fatigue. Energy Balance and Nutritional Deficiencies The total calories eaten by firefighters need to match the total calories expended over an entire duty cycle and, ideally, over an entire season of firefighting. This balance can generally be monitored by body weight. However, the type of food that is eaten and the time that the food is eaten may have a dramatic effect on the body's ability to recover from physical stress. Recommendations for Maintaining Energy Balance Body weight should be maintained over the course of a work assignment. Daily fluctuations of 1 to 3 pounds are normal, due to water loss. Water loss should be replenished before sleeping each night. Loss of weight because of dehydration or loss of lean body mass is a sign of fatigue and decreased work productivity. Sustained weight losses of more than 1 to 2 pounds per week have been shown to decrease immune function. The wildland firefighter's diet should include at least 60 percent of calories from carbohydrates with less than 30 percent of calories from fats. The diet should include about 1.2 to 1.6 grams of protein for each kilogram (2.2 pounds) of body weight. This represents 84 to 112 grams of protein per day for a 70-kilogram (154-pound) individual and 120 to 160 grams of protein per day for a 100-kilogram (220-pound) individual (an ounce is 28.4 grams, about 70 percent of lean meat is protein). This recommendation is based on studies of individuals engaged in arduous aerobic or muscular fitness training. Blood glucose and muscle glycogen (carbohydrate stored in the muscle) need to be maintained or spared during extended, arduous work to maintain immune function, reduce upper respiratory tract infections (URTI), and promote work productivity, cognitive function, and safety. Supplemental foods and fluids containing carbohydrate need to be consumed regularly during the work day. Muscle glycogen levels need to be restored between work shifts through normal diet and also by carbohydrate intake during the "window of opportunity" when muscle glycogen is most easily restored. This window of opportunity is within 15 to 45 minutes after a work shift has been completed. Individuals should eat high-glycemic (quickly absorbed) carbohydrates during the window of opportunity. Crews might need to have supplemental food available between the end of the shift and the next meal. This food may need to be available when crews are being transported (or when they are waiting to be transported) or during any situation when they will not receive a meal within 45 minutes after they have finished their work shift. Crewmembers must maintain hydration at the beginning of and during the work shift. Crew leaders need to watch for crewmembers who may not be carrying or consuming enough water, especially when crews are working in hot, dry conditions. Environmental Stresses Environmental stresses add to the total stress of a wildland firefighter's duties and should be considered when crew leaders evaluate situations that may increase accumulated fatigue. Increases in altitude, heat, humidity, and smoke increase the risk of fatigue. In addition, rough, steep terrain and dangers such as rolling rocks and snags increase physical and mental stress, leading to a high level of fatigue. More rest may be required to recover adequately before the next work shift when crews are working in such conditions. Recommendations for Acclimatization to the Environment Acclimatization periods are necessary for extended work at elevations higher than 6,000 feet or when crews are working in areas with high temperature or humidity. Guidelines should be developed to help managers decide when acclimatization periods are necessary. Work shifts should be shortened with reduced workloads for 2 to 3 days while workers acclimatize to heat stress. Acclimatization to altitude depends on elevation, but a general guideline would be to reduce the duration and intensity of the work shift for 1 day for each 1,000 feet in elevation above 6,000 feet. Individuals differ in their response to environmental stress. Crew leaders need to watch each crewmember for signs of heat stress or altitude-related problems. Shift Length and Sleep Duration The recommendations of the 1989 Wildland Firefighter Work/Rest Cycles Review are still valid. Crew leaders should adhere to the 2:1 work/rest requirement (for each 2 hours of duty time—portal to portal—crewmembers should receive 1 hour of rest or sleep). Longer shift lengths require additional sleep. These data are supported by research for shift lengths up to 24 hours. Recommendations on Shift Length and Sleep Duration The current two-shift system (12 to 14 hours) is the preferred alternative, providing that firefighters are provided 1 hour of sleep or rest for every 2 hours worked. Most rested individuals can tolerate up to a 24-hour work shift without substantial loss of cognitive or physical performance, so long as adequate recovery is given between shifts. Long work shifts (such as shifts over 20 hours) may impair recovery of the immune system (see Research, page 7). Cognitive function is best maintained if the task is interesting or demanding. Changing tasks improves performance during a long shift. Crew leaders need to be especially careful that they get enough rest. Long shifts and lack of sleep impair cognitive function more quickly than they impair physical productivity. Assignment Length Many studies of extended operations have been conducted during military training exercises. Wildland firefighters worked 21-day assignments until the 2000 fire season. Athletes perform prolonged strenuous activities for periods of up to 21 days (such as during the Tour de France bicycle race). Research studies and real-world experience agree that workers or athletes with adequate fitness, nutrition, motivation, and rest can maintain performance for as long as 21 days (for more on assignment length see Risk Management). Recovery Between Assignments A large number of factors need to be evaluated to meet the goal of having crewmembers and leaders begin an assignment in a rested state. No data have been collected on wildland firefighters to evaluate whether the 2-day break between assignments is adequate, or whether the crewmembers and leaders are able to recover adequately during the 2-day break. A related question about rest and recovery is the state of fatigue when crews begin an assignment. Do transport or other logistical factors result in a lack of sleep? A change in time zones or transport to an extreme environment (high altitude or increased heat and humidity) could increase the potential for stress and fatigue. Recommendations for Evaluating Fatigue at the Start of Arduous Work In all situations, the crew leaders should evaluate the need for additional sleep and rest, or the need to acclimatize before beginning an arduous shift. Further research is needed to evaluate the effects of various stressors on the ability to recover between assignments. Guidelines for Monitoring and Enhancing Recovery from Accumulated Fatigue This section summarizes basic guidelines crew leaders can use to identify signs of accumulated fatigue. Visible symptoms that an individual is not recovering adequately from daily stresses vary and depend on the individual. Crew leaders should pay attention to individuals who complain about or manifest two or more of the following signs, especially when the crew has been exposed to situations that can increase the risk of accumulated fatigue. In addition, the field tests described below may prove helpful in situations where leaders expect fatigue to be excessive. Many of the symptoms of accumulated fatigue, when viewed independently of other symptoms, may not indicate accumulated fatigue. When multiple symptoms occur simultaneously, crew leaders should take appropriate actions to reduce stress and enhance recovery for the crewmembers who are affected, or for the entire crew. The symptoms of accumulated fatigue include: Loss of body weight Decreased appetite An increase in resting heart rate An increase in submaximal heart rate at a fixed work load Perception that standard work tasks are more difficult Small (to large) losses in coordination and the ability to do tasks requiring coordination Muscle soreness that lasts more than 24 hours Increase in upper respiratory tract infections such as colds or flu Decreased cognitive function Constipation or diarrhea A change in moods that may include irritability or decreased motivation or desire Crew leaders should know and apply measures to enhance recovery from accumulated fatigue. The basic measures include: Increased sleep in an environment conducive to sleep Reduced duration and frequency of physical work (possible change of duty the following day) Adequate supplemental nutrition and fluids during and immediately after physical work A high carbohydrate diet Monitoring the individuals for recovery Avoiding Accumulated Fatigue All of the symptoms listed above, except the resting and submaximal heart rates, appear only after accumulated fatigue is evident. Of the easily measured field symptoms, only the heart rate measures seem to give some advance warning that an individual is approaching a state of accumulated fatigue. When a crew leader recognizes symptoms in crewmembers, the leader should take steps to enhance recovery. When crews are placed in environments that might increase their risk for accumulated fatigue, when crews are starting an assignment in a fatigued state, or when increased mental and physical stresses are anticipated, crew leaders may choose to monitor individuals. This monitoring is in addition to attention paid to normal symptoms of accumulated stress. Monitoring crewmembers in the field may require some equipment and take a short period of time each day. Current suggestions include two tests that may also be used to evaluate when workers have recovered from accumulated fatigue. Recommendations for Monitoring Accumulated Fatigue Compare daily body weight to baseline weights. During stressful assignments, daily body weight should be recorded when possible each morning before any food or fluids are consumed. This requires that data be maintained over the fire season, including the baseline weight of individuals in a rested state. Daily fluctuations are expected based on dehydration and fluid loss that can be replaced during meals. Consistent patterns of weight loss suggest environments and work that do not allow adequate recovery, or reflect inadequate nutritional intake. Generally, supplemental carbohydrate intake and maintenance of fluids should be adequate to enhance recovery for fit individuals. Monitor morning heart rate response to a standard 4-minute test (requiring 1 minute of easy bench stepping and 3 minutes of rest) for early signs of fatigue and impaired recovery. This fatigue test was evaluated during the summer of 2001 and compared to clinical measurements of immune function. Athletes have used morning resting and submaximal heart rate responses to monitor overtraining. The fatigue test might be appropriate for crews in "at-risk" situations or when accumulated fatigue might be expected. Using this test requires taking baseline measurements and maintaining data on individuals over a period of time to establish patterns (see Field Notes, page 12). For these tests to be practical in a fire camp, the medical tent would need to include a scale and an 8-inch bench. Another alternative would be for type 1 crews to carry a scale and bench. Additional Fatigue Countermeasures Fatigue countermeasures have been studied in military populations and endurance athletes. Although many questions remain to be answered, work cycling is one area of interest that may yield positive benefits for wildland firefighters. Work Cycling—Athletes and coaches have long understood that one of the most effective methods to counteract overtraining (accumulated fatigue) is to vary the training in both intensity and duration so that days of arduous activity are interspersed with less stressful days. This concept allows athletes to avoid illness and accumulated fatigue by scheduling time to recover between hard work periods. The result is reduced time lost to illness, improved alertness, increased total work, and higher productivity. The same principles should apply to wildland firefighters if stressful days are interspersed with less stressful days. This might be done for an entire crew or just for certain individuals. Most physically fit individuals can sustain 1 to 2 days of very arduous work, if they have a less stressful period (1 to 2 days) for recovery. Recovery days do not require inactivity, but do require a change of duty, generally to a duty with less total stress. Little is known about duty cycling for wildland firefighters, but further study might be beneficial. Recommendations for ways to vary the daily intensity and duration of arduous duty should be developed. Fitness—Physical fitness is another known factor in accumulated fatigue in athletes and workers. When team members are asked to do similar training for extended periods, athletes who are physically fit generally exhibit fewer symptoms of accumulated stress than do individuals who are less fit. Research during the summer of 2001 with two type 1 crews suggested that the fit workers did more work (both in absolute terms and adjusted for body weight) and experienced less fatigue. Fitness Recommendations for Wildland Firefighters Aerobic and muscular endurance training before the fire season that is maintained throughout the season would benefit firefighters who routinely work in situations requiring multiple extended arduous work shifts with moderate to high energy output. Fitness standards that are higher than the pack test (walking 3 miles with a 45-pound pack in 45 minutes) should be considered. A fitness training manual should be available to type 1 crews. Individuals who have been relatively sedentary but who wish to take the pack test should begin a training program gradually and slowly build up to the work capacity required for a wildland firefighter. The pack test should be considered a minimum fitness require-ment. Individuals who will be working on the fireline should be encouraged to improve their aerobic (endurance) and muscular fitness. The onset of fatigue as a result of work depends on the individual and is related to many factors. Methods to monitor fatigue within fire crews need to be developed to determine when individuals or entire crews need time to recover. Related Topics Caffeine and other ergogenic (performance-enhancing) supplements may prove beneficial in some extended operations involving arduous work. Studies of athletes have shown that caffeine can increase the utilization of fat during extended moderate work, sparing carbohydrates. In addition, caffeine has been shown to improve cognitive function during periods of extended work. Unfortunately, caffeine is a diuretic and is not advised during periods of heat exposure. A recent (2002) report by the U.S. Army has suggested that new drugs that postpone physical and mental fatigue may prove beneficial, but their long-term effects are not yet known. Commercially available supplements containing ephedra may contribute to life-threatening consequences during exertion and heat stress. It is beyond the scope of this report to consider the growing list of ergogenic aids. Dr. Steven Gaskill processes immune function samples as firefighters return from the line. Other recommendations: Investigate drink or food supplements that could be used during extended operations to help maintain blood glucose. Compare supplements that contain energy and nutrients (such as antioxidants) and a stimulant such as caffeine. A joint effort with the U.S. Army Research Institute of Environmental Medicine or a similar group may be warranted. Gaskill, S. 2002. Work and fatigue in wildland firefighting: a review of the literature. Missoula, MT: University of Montana Human Performance Laboratory. Copies of the complete review and a list of references are available from Brian Sharkey, bsharkey@fs.fed.us. Top Back \| Next \| Cover Page
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