Fighting fire is hard work. This has been a universal truth since the inception of the fire service. No amount of tactics, resources, or technological progress will change this fact. One thing that has changed over the past 100-plus years of the modern day fire service is that firefighter rehab is absolutely necessary. We have come a long way in the concept of firefighter rehab, but there is always room for improvement. Specialty apparatus with comfortable seating, air-conditioning, misting systems, and other amenities specifically designed for rehab are certainly a plus. However, you don’t need to spend millions to have an effective rehab sector.

Following National Fire Protection Association (NFPA) 1584, Recommended Practice on the Rehabilitation of Members Operating at Incident Scene Operations and Training Exercises, does not require that you have a huge budget at your disposal.1 An effective rehab area can be set up using very simple concepts and tools. This article addresses one component of rehab: firefighter hydration.


What is dehydration, and what does it do to the body? Our bodies are made up of about two-thirds water. When someone gets dehydrated, it means the amount of water in the body has dropped below the level needed for normal body function. Under normal circumstances, we lose about two to 2.5 liters of water a day through body waste, sweat, and breathing. Nutrition experts recommend a daily fluid intake of about 1.5 to 2.5 liters for healthy adults under normal living circumstances to prevent a liquid deficit. Small decreases don’t cause problems and go completely unnoticed in most cases. Losing large amounts of water (in excess of 2 percent of body weight) can be a problem.

Strenuous work, particularly in protective clothing and in hot environments, can result in a loss of one to two liters of water an hour. At this rate, a firefighter may rapidly lose a significant amount of body water weight (the amount of water the body contains under normal conditions based on the size and weight of an individual). A loss of 1 to 2 percent of body water weight will compromise work performance, a loss of 2 to 3 percent will compromise mental alertness, and a loss of 3 to 5 percent can compromise the body’s ability to sustain life.2 Thirst is one indicator of dehydration, but it is not an early warning sign. By the time you feel thirsty, you may already be dehydrated.3 Other symptoms of dehydration include the following:

  • dizziness and lightheadedness;
  • headache;
  • a dry or sticky mouth;
  • nausea/vomiting;
  • excessive fatigue, general discomfort, irritability, and unusually decreased work performance; and
  • production of less urine and darker urine.4

Urine color is the best low-tech monitoring tool for detecting possible dehydration. Note: If you are taking a vitamin supplement, this method will not be an accurate indicator; vitamins affect urine color. Clear urine is an indicator that you are very well hydrated. If the urine is light yellow or straw colored, you are sufficiently hydrated and not in any immediate danger. However, if your urine is a dark yellow color, you are already in the early stages of dehydration. Beginning a firefight at this stage may be the precursor to advanced dehydration or worse.5 Dehydration often leads to heat cramps, heat exhaustion, and possibly even heat stroke.

Along with water, the body loses sodium and potassium through sweat. These electrolytes are critical to maintaining the body’s performance level. Without sodium and potassium, the body cannot function properly, and symptoms will appear.6


Heat cramps are the mildest form of heat/dehydration-related illness and are characterized by painful muscle spasms usually in the abdomen, hamstrings, or calves. These cramps can come on very suddenly and are excruciating. Heat cramps are caused by failure to replace the body’s lost sodium, although poor physical conditioning can also play a key role. Heat cramps can be relieved by drinking liquids (what liquids will be discussed in depth later) or through IV therapy. Light massage and application of ice packs to the affective area may also help to relieve muscular pain during these cramps.


Heat exhaustion is a more serious form of heat/dehydration illness. It is the result of even more severe levels of water and sodium losses through sweat. Symptoms generally include weakness and fatigue and clammy and moist skin that may appear flushed or pale. The body will continue to produce sweat at this stage, further depleting itself of electrolytes and water.


The most serious heat/dehydration-related illness is heat stroke. This is very serious and possibly life threatening. It is brought on by a combination of the aforementioned dehydration factors as well as the body’s failure to regulate its core temperature. Sweating now stops. It is followed by mental confusion, delirium, loss of consciousness, convulsions or seizures; if left untreated, it could lead to coma or death. The core temperature of an individual experiencing heat stroke can be greater than 106°F; the patient will present with hot, dry, and mottled skin.

Dehydration and all the aforementioned related medical problems can further be complicated by age, physical fitness level, stimulant use (such as caffeine), and preexisting medical problems. Even if none of these risk factors exist, we firefighters are already predisposed to dehydration by the very nature of what we do. Turnouts raise the body’s core temperature as well as eliminate the body’s primary method of cooling itself. The body produces sweat, which evaporates and cools the skin, helping to regulate body temperature. When encapsulated in turnouts, this evaporation cannot take place. The body’s temperature continues to rise as we vigorously exercise (firefighting). We sweat more, losing more electrolytes and water, while still not being allowed to cool off. It is a vicious cycle that can rapidly overheat and dehydrate even the most physically fit firefighters.


Dehydration must, for all these reasons, be combated before the firefight begins. Limiting the use of stimulants such as caffeine, maintaining physical fitness, and keeping yourself adequately hydrated throughout your shift are ways to stop dehydration before it starts.

Avoid caffeine throughout your shift. It has been proven to cause major changes in the kidneys known as a diuretic effect. Caffeine increases the blood flow in the kidneys while inhibiting the reabsorption of sodium and water. Caffeine also has been known to weaken the detrusor muscles in the bladder, which provokes the need to urinate.7 In a nutshell, caffeine makes you dispose of the electrolytes your body so desperately needs. The liquid you consume in the form of caffeinated drinks, such as coffee or soda, is not enough to overcome dehydration, and the diuretic effects make what little liquid your body takes in less effective.

There is some controversy surrounding caffeine and dehydration. A Web search on this topic reveals several proponents of caffeine use and sports activity. However, the majority of the debate surrounding caffeine focuses on athletes and their use of caffeine as a sports stimulant. In these cases, the athletes were prehydrated and under the supervision of sports trainers in a regimented training program. For this reason, it is recommended that firefighters use caffeine in moderation.

A high level of physical fitness helps combat dehydration before it starts. Fitness improves heat regulation, creates a greater blood volume, and allows you to adjust more easily to vigorous exercise in a hot environment. Fit firefighters typically carry less body weight and are acclimated to intense physical activity. Furthermore, in general, firefighters engaging in fitness-related activities throughout their workday typically maintain an adequate level of hydration by consuming water or sports drinks during and after workouts.

Maintaining an adequate level of hydration throughout your workday is of the utmost importance. Unlike most athletes, when and for how long we are expected to perform is an unknown factor for firefighters. At a moment’s notice, we may be called to engage in very strenuous activity in a hot environment. Once the alarm sounds, it is too late to try to prehydrate for a fire. Maintaining hydration throughout a shift is the only way to ward off dehydration later.

Prehydrating begins the day before a shift. If engaging in physical activity during your day off, it is vitally important to stay hydrated. Drinking alcohol or large amounts of caffeine before a shift will potentially affect your performance when called to duty. For on-call volunteer firefighters, staying hydrated while “off duty” is an absolute must. Approach your days off from the mindset of “the night before the big game.” Athletes certainly would not allow themselves to become compromised by dehydration, drinking alcohol, or consuming an excessive amount of caffeinated drinks the night before they want to perform at their best. To be at the top of your “game,” you must have the same mindset before a shift.

As discussed before, urine color is an easy way to measure your hydration level. Throughout your day, this simple method may be used to stay prepared. Here at the Mesa (AZ) Fire Department, dehydration, especially during the summer months, is a major concern, as you can imagine. For this reason, we have placed charts (SNTTM Handout #14, Web site listed in endnotes) (5) in the bathrooms of the stations that help firefighters gauge their hydration levels. This simple tool illustrates what hydration level you currently have based on a color chart. We have had great success with this simple regulatory method.


What you drink to prevent dehydration can be very important. A good rule of thumb is, if physical activity has lasted for less than 40 minutes, drink water; if the activity has lasted for more than 40 minutes, drink a sports drink to replace energy and electrolytes. Picking sports-drink type products to stock in the station and in the rehab sector can be very confusing. They are not all created equal, and cost is always a factor. So how do you pick a good sports drink to place in rehab? With some simple baseline knowledge, choosing a sports-type drink can be easy. First, let’s discuss what a sports drink is and what it does.

A sports drink is a combination of water, carbohydrates, and electrolytes. The water replaces the water the body loses through sweat. The carbohydrates replace energy stores in the body to increase performance and stamina. Electrolytes replace those that the body has lost and needs for continued performance. The glucose and sodium also enhance fluid absorption in the small intestines, thus rapidly replacing what the body has lost. The water, carbohydrates, and electrolytes work together to keep the body’s thirst mechanism active. Thirst prods firefighters to drink more, thus they become better hydrated. Water alone tends to eliminate the body’s thirst mechanism.8

Picking a sports drink that will rehab firefighters properly is not that difficult. All the information you need to make a wise choice is on the bottle label. Start with the calories the drink provides. A good sports drink should provide between 50 and 80 calories per serving, which will properly replenish the energy stores of firefighters recovering in rehab. Additional calories will cause the absorption rate to slow and the body’s metabolism to become inefficient.

Next, look at the electrolytes contained in the drink. The sports drink should contain between 100 and 170 mg of sodium to adequately replenish the body’s electrolytes. A lesser quantity may cause firefighters to become electrolyte depleted (hyponatremic), which may lead to heat cramps or worse.

Finally, look at the carbohydrate content. Research has shown that a 6 percent concentration of carbohydrates allows for rapid fluid absorption and improves performance. To calculate the carbohydrate percentage of a beverage, divide the amount of carbohydrates in one serving (usually listed in grams) by the amount of fluid in milliliters (8 oz. = 240 milliliters) per serving, and then multiply by 100. The label may list this value for you next to the total grams of carbohydrates per serving.9

The type of carbohydrate is very important. Choose a drink that has glucose or sucrose as the carbohydrate source, because they are quickly absorbed by the body and easily utilized as energy. Drinks with high-fructose corn syrup or galactose can upset the stomach and can be a far less effective energy source.10 In general, the less expensive sports drinks (typically store-brand types) contain corn syrup as the carbohydrate. This falls into the “you get what you pay for” category. Although the drinks may be cheaper, the minimal cost savings may not be worth it if crews in rehab have stomach discomfort (and in some cases nausea from gastrointestinal distress) and possibly may not be able to return to the firefight.

Some manufacturers are now adding protein to sports drinks. The theory behind this is that protein aids in recovery time following strenuous muscular work. However, the sports nutrition community is divided on this subject. Protein will certainly not hinder firefighters’ recovery time; however, the amount of carbohydrates, electrolytes, and calories a drink contains should be of primary concern.11 Until there are further studies done defining the attributes of protein in sports-type drinks, protein should not be a major determining factor when choosing drinks for firefighter hydration.12

Avoid fruit juices. Although healthful, they are not ideal fluid replacement beverages because of their high carbohydrate and low sodium content. Fruit juice is absorbed at a slow rate and can cause stomach discomfort and gastrointestinal distress. Even when diluted with water to help absorption rates, they still do not contain enough sodium to be effective rehab choices.

Do not choose drinks with carbonation, which can cause a burning sensation in the throat (discouraging drinking), cause gastric distention and discomfort, and slow the absorption of liquid into the small intestines.

As noted, avoid drinks with caffeine. Many “energy drinks” are sold in health food stores and are marketed as energy boosters for pre- or post-workouts. However, energy-type drinks do not contain the carbohydrates and electrolytes needed for rehab and should not be used. Some sports drinks may contain caffeine, which is not plainly stated on the front of the bottle. That’s why it is important to take the time to research products before buying them to stock a rehab unit or area.13

Taste, of course, is an important factor. The flavoring in sports drinks encourages consumption. Factor taste in when looking at products to purchase for rehab. Provide a wide variety of flavors to encourage members to consume the drinks often. Taste, however, should not be the most important factor. Consider the caloric intake, type of carbohydrates, and sodium levels first; taste should be a secondary concern.

There is a common misconception that sports drinks should be diluted with water before consumption. This is not so. Water can and should be stocked with sports-type drinks in rehab (keeping the 40-minute exertion rule in mind). However, sports drinks are formulated to provide the greatest benefit when consumed without dilution. The theories behind dilution of sports drinks most likely stemmed from individuals trying to limit calories when “dieting” and not fully understanding how and why sports drinks are designed the way they are. Dilution of sports drinks will not provide the proper amount of carbohydrates and electrolytes for firefighter rehab when exertion has been more than 40 minutes.

Once you have selected the sports drinks your department will purchase, decide where and when they will be available to firefighters. Placing these drinks on a rehab unit along with water and snacks is a good start, but it does not completely address firefighter hydration and rehab.

Since, as stated, combating dehydration starts before the fire, drinks should be available in the stations so firefighters can maintain an adequate level of hydration throughout their shift. Mesa Fire has made bottled water and sports drinks available to our members in this way for many years. The policy has been well received and is considered a privilege that has not been abused. Along with placing these drinks in the stations, remind members of the importance of maintaining their hydration level throughout their shift. Placing the color charts in the bathroom at the beginning of the summer months as well as sending out yearly dehydration educational material has been an effective way for the Mesa Fire Department to remind our membership of how important these concepts are.

Make sports drinks and water available on each apparatus to facilitate company/crew level rehab (also referred to as self-rehab by the NFPA). By placing sports drinks and water on each unit, crews may hydrate throughout their day. Rehab units often are called only to scenes where a large number of resources are required. However, the activities that crews engage in throughout the day as single units can be just as taxing on their hydration levels as a large incident. Their hydration level is steadily attacked throughout a shift as crews engage in activities such as drills, business inspections, single-unit response calls, and equipment maintenance. Having the ability to rehydrate at the crew level is critical. On each Mesa Fire Department apparatus, we have placed a small store-bought ice chest. Each morning during the apparatus check, the engineer (driver/operator) places sports drinks and bottled water in the cooler along with fresh ice. This concept has been an easy fix for our hydration needs and has proven to work effectively at the company level.

NFPA 1584 lists the following as basic rehab practices:

  • medical evaluation (heart rate, blood pressure, and temperature) and treatment,
  • food and fluid replacement,
  • relief from climatic conditions (out of smoke, shade, air-conditioning, for example),
  • rest and recovery, and
  • member accountability.

Using these simple concepts as guides, every department can achieve effective rehab. Although we here at Mesa Fire are fortunate enough to have several specialty vehicles designed specifically for rehab, often it is the simple things such as those described above that truly make a difference. With some basic research into sports drinks and their contents, you can be well on your way to providing adequate firefighter rehab for your members. There is a wealth of information on the Internet on this subject as well as in NFPA 1584. I encourage you to continue to investigate sports drinks and rehab concepts.

To learn more about dehydration, firefighter heat stress, and rehab concepts, go to; select “personnel and wellness” division, and click on the “heat stress” link for a very funny and informative DVD production available for viewing or downloading.

I would like to thank Captain Holly Button and Captain James Johnson of the Mesa Fire Department Wellness Office for providing some of the research for this article.


1. NFPA 1584, Rehabilitation of Members Operating at Incident Scene Operations and Training Exercises, NFPA Technical Committee on Fire Service Occupational Medical and Health, Feb. 6, 2003.

2. Glen A. Selkirk and Tom M. McLellan, “Physical Work Limits for Toronto Firefighters in Warm Environments: Defining the Problem and Creating Solution,” WSIB Research Grant #01 005: Final Report. Defense R&D Canada – Toronto, Sept. 2003, 4-5.

3. Elizabeth Joy, M.D., FACSM, “Heat Illness,” Sports Medicine Tip Sheet,” University of Utah, Salt Lake City, 1-2.

4. Inter-Association Task Force on Exertional Heat Illnesses, “Consensus Statement: Overall Strategies for the Prevention of Exertional Heat Illness,”, accessed on 08/15/2006.

5. SNTTM Handout #14 “Am I Dehydrated? Urine Color Chart”, accessed 08/13/06 (may also be accessed by typing “SNTTM Handout #14” into “Google” search engine).

6. AWC Executive Wellness Center “Hydration and Heat Disorders,” Accessed on 08/10/06.

7. Jack Hartley, “Caffeine and Sports Performance,” Vanderbilt University Research Paper,, accessed 08/15/2006.

8. City of Mesa (AZ) Fire Department, Firefighter Wellness Office, “Heat StressAwarness” DVD, 2006, directed/produced by Captain Holly Button.

9. Gatorade Sports Science Institute, “How To Read a Sports Drink Label” flyer, 2000.

10. Leslie Bonci, “A Quick Boost,” a guide to energy drinks and bars. T&C Sept. 2002 at

11. “The verdict is in: Most of us can skip drinking protein-enhanced sports beverages during exercise,” Julie Deardorff, Chicago Tribune, , accessed 9/13/06.

12. “Studies Divided on Value of Adding Protein to Sports Drinks,” Robert Preidt,, accessed on 9/13/06.

13. “Fluids 2000, How Sports Drinks Work,” Gatorade Sports Science Institute, 07/27/2000.

DEREK WILLIAMS has been a firefighter in the state of Arizona for 15 years. For the past 11 years, he has served as a firefighter/paramedic in the Mesa (AZ) Fire Department, where he is assigned to a ladder company and is a member of the hazardous materials team. He has an associate’s degree in fire science and paramedicine from Mesa Community College, where he has also been an instructor. He also serves part time in the Firefighter Wellness Office, assisting in the area of firefighter injury management.


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