The Importance of Staying Hydrated

Every firefighter understands how important water is for fighting fires. It’s engrained in our minds from the time we enter the academy until the day we retire: “Put the wet stuff on the red stuff.” The part that’s well overlooked is how the “wet stuff” can help a firefighter perform in the heat throughout the day.

There have been many changes and advancements made to the industry over the years. Equipment has changed. Gear is lighter and more tolerable to the extreme conditions of firefighting. Fire trucks now have GPS navigation and computerized pumping systems. But with all of these advances in the industry, and as more and more research is conducted on the physical demands of firefighting, two facts remain unchanged: Firefighting is hard work, and it takes knowledgeable, competent and physically fit people to do the job. No amount of technological progress, tactical education or resources will change this.

In most stations, your shift starts with checking your gear, SCBA, med supplies and looking over the apparatus (usually with a cup of coffee in hand), but do you ask yourself, Am I physically ready? I imagine 100% of you nodded your head in affirmation to that seemingly rhetorical question.

Hydration & the Human Body
The human body is 66–70% water. Under normal circumstances, the human body loses about 35–90 oz. of water a day through body waste, sweat and breathing (Maughan, 2003). During normal athletic activity, the body can lose 8–16 oz. of water per hour. The extreme conditions of firefighting demand more than this. On average, working firefighters should anticipate losing 50–70 oz. of sweat in 30–45 minutes of fireground activity (Levine et al., 1990). For a 200-lb. firefighter, a 2% sweat-induced loss of body weight would require a post-exercise fluid intake of about 96 oz. or more, considering the individual was well hydrated before the call.

A Matter of Life & Death
Hydration is critical for optimal performance. Progressive dehydration from exercise (or fireground operations) impairs performance, mental capacity and perception of effort, and it can be life-threatening. With as little as a 2% shortage of body water, the ability to perform a high-intensity activity can be greatly impaired (Kleiner, 1999). The combination of the hot environment and the protective gear insulating the firefighter can produce dangerous conditions of hyperthermia and dehydration.

Properly hydrated, well-conditioned firefighters are therefore much better able to contend with heat stress than their unconditioned and/or dehydrated counterparts. Put that into the context of your crew, which is only as strong as its weakest member. If you don’t hydrate yourself properly before arriving on the fireground, you’re not only putting your own life in danger, but the lives of your crewmembers as well, because your performance level could be greatly reduced (IAFF, 2006). For these reasons, dehydration must be addressed before the firefight begins.

Don’t Rely on Thirst
Unlike most athletes, the date, time and duration of the event are unknown factors for firefighters. At a moment’s notice, you may be called to engage in very strenuous activity in a hot environment. But once the alarm sounds, it’s too late to try to prehydrate for a fire.

Maintaining hydration throughout a shift is the only way to ward off dehydration later. Don’t rely on thirst. The brain gets the signal that the body is thirsty after 1% of body weight has been lost. So by the time an individual develops the thirst mechanism, they are significantly dehydrated (Sawka and Pandolf, 1990).

How to Hydrate
To stop dehydration before it starts prior to the alarm for a service call, you must limit the use of stimulants, such as caffeine, avoid carbonated beverages, maintain physical fitness and stay adequately hydrated throughout a shift. Drink plenty of water at regular intervals, and aim to replace fluids at the same rate that they’re lost. At minimum, consume 64 oz. of water a day (Casa et al., 2000). Increase that amount when exercising on duty and after you’ve completed your workout to avoid being dehydrated at the scene.

As mentioned, avoid drinks with carbonation, because they can cause a burning sensation in the throat, which can discourage drinking, cause gastric distention and discomfort, and they can slow the absorption of liquid into the small intestines (Williams, 2006).
Caffeine increases the blood flow to the kidneys while inhibiting the reabsorption of sodium and water. This has been proven to cause major changes in the kidneys known as a diuretic effect. For this reason, it’s recommended that firefighters use caffeine in moderation (Williams, 2006).

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. Better-conditioned firefighters will carry more water and lose fewer electrolytes via sweat, thus enabling them to rehydrate quickly and completely.

Muscle mass is relatively high in water content (about 75%) compared to fat (generally 25% less). So the leaner the individual, the greater ability their body has to store water (IAFF, 2006).

Other Daily Recommendations
The World Health Organization recommends drinking 6 to 8 large glasses of water a day. But remember: This is only to maintain normal fluid balance and does not take into account the extra fluid loss caused by firefighting activity. Optimally, try to consume half your bodyweight in ounces of water a day. So if you were a 200-lb. individual, you would drink 100 ounces of water a day.

Drink before, during and after your shift. Get into the habit of taking on fluids throughout the day; try to have a water bottle on the truck and around the station. And always try to drink more fluids than you need. Smaller quantities at frequent intervals help optimize hydration.

Here are some other tips to help you stay hydrated throughout the day:

Prior to Fireground Operations (or exercise)

  • Drink at least 16 oz. of water an hour before operations/exercise to ensure your fluid levels are up to par. If you’re dehydrated prior to exercise, try to consume 32 oz. of water.
  • Drink 8–10 fl. oz. 10–15 minutes.

During Fireground Operations (or exercise)

  • Drink cool (40 degrees F), dilute fluids at a minimum rate of at least 8 oz. every 15 minutes or 34 oz. per hour. Those who are dehydrated must drink 8 oz. every 10 minutes or 50 oz. per hour.
  • Drink 8–10 oz. every 10–15 minutes.
  • If exercising longer than 90 minutes, drink 8–10 oz. of a sports drink (with no more than 8% carbohydrate) every 15–30 minutes.

After Fireground Operations (or exercise)

  • If the exercise (fireground activity) lasts for less than an hour, the body should have sufficient electrolyte and carbohydrate supplies to maintain optimal performance. Therefore, for short periods of exercise, water is just as good as sports drinks.
  • If exercise (fireground activity) lasts for more than an hour, use a sports drink with electrolytes and carbohydrates along with water to rehydrate the body.
  • Weigh yourself before and after exercise and replace fluid losses, drink 20–24 oz. of water for every pound lost.
  • If no water was consumed during exercise (fireground operations), aggressively rehydrate at a rate of 16 oz. of fluid every 15–20 minutes.

Want to Learn More?
For more information on proper hydration, check out the IAFC’s booklet, “Rehabilitation and Medical Monitoring: An Introduction to NFPA 1584”at http://www.iafc.org/Operations/ResourcesDetail.cfm?ItemNumber=4781.

And to read results from an extensive rehab study completed by the Orange County, Fla., Fire Authority, visit http://tinyurl.com/OC-hydrationstudy.

Burr, R and U.S. Army Research Institute of Environmental Medicine. (n.d.) Thermal Heat Stress Protocol for Firefighters and Hazmat Responders. Retrieved on May 29, 2011, from www.iaff.org.

International Association of Firefighters, International Association of Fire Chiefs, American Council on Exercise. Peer Fitness Reference Manual. IAFF. Washington, D.C., 2006.

Institute of Medicine. Dietary Reference Intakes for Water, Sodium, Chloride, Potassium and Sulfate. National Academy Press: Washington, D.C, 73–185, 2005.

Kleiner, SM. Water: An essential but overlooked nutrient. In Journal of American Dietetic Association. Retrieved May 31, 2011 from www.ncbi.nlm.nih.gov/pubmed/9972188.

Maughan, RJ. Impact of mild dehydration on wellness and on exercise performance. In European Journal of Clinical Nutrition. Retrieved May 29, 2011, from http://www.nature.com/ejcn/journal/v57/n2s/full/1601897a.html.

Casa, DJ, et al. National athletic trainers association position statement: fluid replacement for athletes. Journal of Athletic Training. 2000;35(2): 212–224.

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

Sawka, MN and Pandolf, KB. Effects of body water loss on physiological function and exercise performance. Perspectives in Exercise Science and Sports Medicine. 1990;3: 1–38.

Skinner, JS. Fighting the fire within. Firehouse magazine. 1986;46: 66.

Smith, DL, Manning, TS, Petruzzello, SJ. The effect of strenuous live-fire drills on cardiovascular and psychological responses of recruit firefighters. Ergonomics. 2001; 44(3): 244–254.

Williams, D. Firefighter hydration during rehab. Fire Engineering magazine. Retrieved on May 15, 2011, from www.fireengineering.com.