Hydrate or Die...It's the Law of the Desert!

As a professional firefighter, the subject of hydration is something that I do not take lightly.  Having served as the Health and Fitness Coordinator for my department since 1999, one of my responsibilities is to educate my fellow firefighters about the importance of proper hydration...not just for our survival, but for those who depend on us.

You see, if we are not properly hydrated, then we are not capable of performing at our highest level of performance...which ultimately means that we are not providing the level of service that our 'customers' expect.  If I am actively involved in firefighting and life safety operations, and I succumb to heat exhaustion due to hypo-hydration, a series of potential outcomes begin to come into play...none of them being good.

If I go down in a fire, the stress level that we normally work under is immediately increased...exponentially. Thereby creating a greater workload for the rest of my crew, as they are forced to not only continue firefighting and search/rescue operations...but now they have to somehow manage getting me out of a deadly environment as well. Often times this results in an increased potential for fire spread, as well as a decreased effort to search and/or rescue trapped victims within the structure.  Working as a firefighter in the Arizona summer heat, creates an even greater need for proper hydration, in order to maintain a high level of performance.

Yesterday, I was riding with The Ride 430 Challenge team on our weekly training ride.  The route we took was nothing terribly daunting...about 70-miles.  Understand however, that it is August...and in Phoenix that means temps that can soar quickly to well above 100-degrees, with the fun little addition of humidity upwards of 40%.  Many of you reading this live in climates where you experience humidity rates in the 90's, and may be thinking "40%...that's nothing!"  What you need to keep in mind however, is that climates are relative.  We adapt and acclimatize to the environments that we live in...so for us here in Phoenix, August can be quite brutal.

I wont bore you with the details of our ride, but suffice it to say that a number of my team members suffered out there in the heat...and ended up with varying levels of heat stress and heat exhaustion.  

So how can we protect ourselves against heat related emergencies?  

The first, and possibly the best way to protect ourselves is simple...don't perform strenuous activities in the heat.  Pretty simple, right?

Not so much.

This is the real world.  And in the real world, people have to be out in the heat.  Firefighters have to battle fires during the summer, and athletes have to train.  As athletes however, we can minimize the impact of the heat by doing our best to plan our outdoor training sessions so that we are limiting our total heat exposure time.  This means starting early!

What else can be done to reduce or chances of heat related emergencies?

How about employing proper hydration and nutrition strategies...that makes sense huh?  Sometimes however, that is easier said than done.  It takes commitment and discipline...planning ahead, and sometimes a little sacrifice.

Sacrifice? You bet!

If you are training early Saturday morning, then you probably shouldn't be out 'getting your drink on' Friday night.  You should probably eat clean and get adequate amounts of rest that night...which for some, means that you probably shouldn't go out on Friday.  That could be considered a sacrifice...right?

How many of you know how to hydrate properly?  My guess is that most of you think you know...but have never really researched the topic, or been formally educated.  For those of you who have it down, what follows my simply be a review for you.

First of all, let's talk about fluid replacement...because that's really what hydration is...replacing fluids in our body that have been utilized for a variety of human functions...thermo-regulation being one of the biggies.

Thermo-what?

Thermo-regulation is the process of maintaining a 'normal' body temperature range.  As ambient temperatures rise, so too do the demands placed on the body for cooling.  A number of mammals thermo-regulate through the process of panting.  Just like when I take my dog Tuck out for a session of Frisbee...he quickly begins to pant as his body core temperature begins to rise.  

We humans however, use the process of evaporative cooling to maintain our body's normal core temperature range.  As our core temperature begins to rise, our body begins to produce sweat, excreting it to our skin's surface, where it evaporates and cools the body.  This process is highly dependent upon fluid within the body...that's where the sweat comes from.  

Think of your body as a big jug of water.  It can only hold so much at one time.  As we take water from it, the total volume held within it begins to decrease.  If we don't replenish it, the jug runs dry.  Sweating takes water from our 'jug' to keep us cool.  If we don't replenish the supply, we will soon run dry.

Our sweat not only contains water, it also contains electrolytes such as sodium and potassium.  These electrolytes are important for specific human functions such as muscle contraction, proper cardiac muscle activity, etc.  When these electrolytes are depleted, a variety of unwelcome events can begin to occur, such as muscle fasciculations and cramping, peripheral numbness and tingling, heart arrhythmias, vision problems, headaches, vomiting, etc.

No bueno!

I've already mentioned that hypo-hydration...commonly known as dehydration...can lead to decreased performance levels.  This is due to increased physiological strain and  an increase in perceived exertion levels to complete a given task.

That means if you are out training, and you are dehydrated (by as little as only a 1% loss of total body water volume), your body is going to have to work harder to complete the task, than if you were adequately hydrated...thus creating a cyclic, progressive rate of performance decrement.  

So let's look at how we should hydrate our bodies...before, during, and even after exercise.  The following information is not simply based on my personal thoughts...no sir!  It's evidence-based information from the American College of Sports Medicine (ACSM) Position Stand on Exercise and Fluid Replacement.  It is what I base all of my hydration education and protocols on...used on myself, my athlete clientele, and my firefighters.

Before Exercise

Pre-hydration is extremely important.  The goal is to begin physical activity adequately hydrated (euhydrated), and with normal plasma electrolyte levels.  A good rule of thumb to follow is to consume 17-20 ounces of fluid (400-600ml) 2-3 hours prior to training or competition.  If you do not produce urine, or your urine is dark in color, slowly drink more fluid (~ 3-5 ml/kg) about 2 hours before the event. By hydrating several hours prior to the event (such as listed above), there is adequate time for urine output to return to normal before the onset of the event.

What should you consume prior to the event?  There is a great deal of research into this topic, and many feel that plain water is best  to consume prior to an event or training session.  However, there is some merit to consuming fluid with mild amounts of sodium, which has been found to stimulate thirst and retain needed fluids.

During Exercise

The goal of replenishing fluids during exercise is to prevent excessive dehydration, resulting in decreased performance levels.  Recent studies have found that as little as 1% total body water loss, has profound effects on physical performance.

Low to moderate exercise intensities, performed in mild temperatures, have been found to result in an average of 500ml of fluid loss per hour (16-20 ounces).  This aligns well with the often followed rule of thumb that states you should consume one bottle per hour (for endurance athletes such as cyclists).  

The same level of intensity however, performed in hot climates (like Phoenix!) has been shown to result in significantly higher rates of fluid loss... ~2-3 liters per hour (68-102 ounces).  So if you are following the one bottle per hour rule, you may find yourself on the wrong end of the hydration curve, quite quickly!

This, like nutrition, can be quite specific to the individual, and may need to be 'dialed in' over time to find just the right amount of fluid intake that provides performance enhancement benefits, while preventing that bloated 'over full' feeling.

Post Exercise

The goal of consuming fluids following exercise, is to replace any fluid and electrolyte deficit that was created during activity.  How aggressive one is about replacement is once again individual specific...but generally speaking, the quicker the better.

In most cases the consumption of normal meals with a sufficient amount of plain water is all that is required to return the body to euhydration.  In my personal experience however, most athletes do not maintain enough fluid intake during exercise, thereby requiring more aggressive post-exercise replacement strategies to quickly return the body to normal levels.  

Once again, the consumption of mildly salted drinks and foods will help to stimulate thirst, as well as help to retain those fluids that have been consumed.

How much fluid should be replaced?  The ACSM recommends that ~1.5 liters of fluid be consumed for each kilogram of body weight lost.  To determine this amount, it is necessary to weigh yourself prior to exercise, and again immediately (or as close as possible) after your activity.  The difference between your start and finish weights is your total body weight loss.  To find your weight in kilograms, simply divide your weight in pounds by 2.2...or just use 2 to make it simple.  Then consume 1.5 liters of fluid for each kilogram lost.

It's that simple.

I hope this has helped.  Stay tuned for my next post...which will look at nutrition, and how it can play a role in hydration and overall performance.

As always...I thank you for reading!

Yours in Health and Performance,

John