Hydrate or Die®

By Steve Isaac (aka Chief)

A previous article explained how to calculate and satisfy your body's fuel needs for ultra events like the WaterTribe Challenge.  Hydration was covered but many details were left out.  This article will fill in the the missing information.

You can customize this article so estimates further down in the article will be appropriate for your weight.

Enter your weight in pounds:     Valid between 50 and 500 pounds.

A person in good health requires up to 4 liters of water each day just to carry out normal metabolism.  This fluid is replaced by the fluids we drink and the food we eat during the day.  When extra energy is required more water is consumed to produce that energy.  In addition to normal metabolism, your muscles produce 8 to 10 times more heat when they are working hard than when at rest so you need to cool your machine.  The body will divert blood to the skin and produce sweat which evaporates and cools the blood.  Your core temperature remains stable at 98.6 degrees because your skin temperature might be cooled to about 77 degrees.  Everything is stable and you perform at your best.

Until you get dehydrated.  As sweat is produced your blood becomes thicker and your heart has to beat faster to make up for it.  Less fuel and oxygen is available to your muscles.  Your performance suffers.  If you don't replace the lost fluids soon, you will become seriously ill.  A loss of only 2% of your body weight is enough to cause initial symptoms.  A loss of 6-8% can cause death.  Consider that a 180 pound man only needs to lose 1.6 liters of water to display symptoms of dehydration.  

Just recently a Minnesota Viking player died of heat stroke during a practice session.  Proper fluid and electrolyte replacement may have prevented this tragedy.  Don't let dehydration take its toll on you.

In his book titled Serious Cycling and High Tech Cycling, Dr. Edmund Burke says, 

"With vigorous exercise in hot or humid conditions, you can start to feel the effects of dehydration in less than one hour. You'll start to feel a decrease in your strength and energy. After two hours, you may start to feel the more serious effects – headaches, cramps or nausea. In fact, dehydration is a key factor in bonking, or hitting the wall. Eventually heatstroke and heat exhaustion can set in."

But dehydration is only part of the problem for athletes working in high heat and humidity.  When the ambient temperature exceeds 95º F, evaporation of sweat is the only cooling mechanism available to the body.  If, at the same time, ambient humidity exceeds 80 percent, the ability to dissipate heat from evaporation declines.  Sweat will continue to pour from your skin but your core temperature will rise leading to serious heat related illness which can be life threatening.

Heat and Dehydration Illness

Here are some interesting facts that impact how your body deals with heat and exercise intensity. 

• You can easily loose 1 to 3 liters of sweat per hour on a hot day. 

• You can lose 1 to 2 grams of salt per liter of sweat.

• Your body can only absorb about 1 liter of water per hour

• Water and electrolytes (salts) must be kept in balance

Notice that it is easy to lose more water than you can replace every hour.  This is a fatal formula if you don't take steps to keep everything in balance.  

So let's examine what can happen if you don't keep your body happy.  Remember, 2.2 pounds = 1 liter of water.

Note all calculations round down to the nearest whole liter with a minimum of 1 liter.

Slight Dehydration is when you have a net loss of water equal to about 2% of your body weight.  This can happen in about one hour.  (Based on your weight this is a net loss of  1.33 liters)

Symptoms:  Decreased performance and endurance

Treatment:  Drink more water and sports drinks and/or slow down

Heat Cramps may begin when you have lost about 4% of your body weight.  One more hour for a total of two hours is all it takes.  (Your body's net loss of  2.67 liters)

Symptoms:  Headaches, muscle cramps or spasms often when you stop to rest

Treatment:  Drink sports drinks to replace lost electrolytes and fluid

Heat Exhaustion is more severe and starts with about 6% net weight loss of sweat.  It only takes one more hour for a total of three hours.  This condition is dangerous and must be rectified immediately.  (Your body's net loss of  4.00 liters)

Symptoms:  Malaise, headache, weakness, nausea, loss of appetite, vomiting, dizziness when standing up or sitting down.  Victim is still sweating, normal mental state, and is coordinated.  Core temp no higher than 104ºF.

Treatment:  Stop all exertion and move victim to a shady spot, loosen restrictive clothing, administer sports drinks and water.  Place cold packs along neck, arm pits, chest wall, and groin but not directly against the skin.  Fan while splashing with water or soak in cool water until the core temp is reduced to about 100ºF.

Heat Stroke occurs at about 7% weight loss of sweat.  Your body does not have enough water left for cooling and other functions.  You begin to shut down.  Death is imminent.  (Your body's net loss of  4.67 liters)

Symptoms:  Confusion, disorientation, bizarre behavior, may appear intoxicated, seizers, coma, rapid heart rate, low blood pressure, rapid respiration.  Sweating may be present but often is not.  Core temp 105ºF or more.

Treatment:  Cool the victim as quickly as possible, use ice, cold packs, fanning, even immerse the victim in cool water if possible.  Administer saline solution if possible but vomiting or aspiration is a risk.  If necessary, use an IV if someone in the group is qualified and has the equipment.  Treat for shock.  Evacuate the victim to a hospital.

Notice that heat stroke is a life threatening condition.  If you are in the wilderness and cannot get to a hospital, you must restore fluid and electrolyte balance in addition to reducing the core temperature.  First priority is to cool the victim.  Dowsing with water and fanning is very effective.  Ice or cold packs can also be used.  Don't actually put the victim in a cool stream or lake because they may drown.  Trying to administer fluids to a victim that is unconscious or having seizures is dangerous due to the possibility of vomiting and aspiration.  Do what you can.  Cooling the victim may help them recover enough to drink.  If not, use an IV if you have the knowledge and equipment.  If that isn't possible, administer the fluids in a very small amount but at frequent intervals.  Maybe using only an eye dropper.  The solution MUST contain electrolytes.  You can make a saline solution which contains 5-7 grams of salt ( about 1 teaspoon) per liter of water.  Don't use a sports drink unless you have nothing else.   Note that this is a much stronger solution than you would normally use for hydration.

Tip:  The color of your urine is one of the best indicators of your hydration condition.  Clear to pale yellow is good.  Dark yellow, orange, or even brown can indicate dehydration or a serious medical problem.  But certain vitamins can effect the color of your urine.  Take your supplements with your evening meal so you can use your urine as a hydration signal during the day.  

You should monitor how many times you have to urinate.  Once every couple of hours is about right.  Check the color each time.

Hyponatremia  or Over Hydration

The flip side of dehydration is hyponatremia which is a build up of excess fluid in the brain and lungs that results from electrolyte depletion along with drinking plenty of water.  Usually it takes high exertion for a period of four hours or longer when the athlete is drinking plenty of water but not replenishing electrolytes that are excreted in the sweat.  This condition is often confused with dehydration because many of the symptoms are similar.  Treating the condition with plain water only exacerbates the problem.  Death is a very real possibility.

The symptoms are:

• respiratory distress

• nausea

• disorientation

• pink frothy sputum

Treat with sports drinks containing sodium and potassium.  Salt can be used or make a saline solution.  You must get electrolytes into the victim.

How to Determine Your Hydration Needs

Hydration needs are different for each person and for each climate.  It can be very difficult to determine these need just by sweat or exertion.  For example someone running an ultra marathon may be sweating buckets but all the sweat is evaporated and their shirt is as dry as the sand.  On the other hand, a sea kayaker in Florida during August may be cruising along without much effort but their shirt is wringing wet.  They are sweating but little to no evaporation is taking place.  Or consider a cross country skier in a very cold climate.  The ambient temperature cools their body, but they loose a lot of water through breathing very dry air.

There is a very simple experiment you can use to determine your hydration needs under any condition.  You should do this a few times during your training sessions so you begin to know your body and its response.

1. Select a training session that will last for one hour or more.

2. Weigh yourself buck naked and dry.

3. Go out and do your training session.  You might want to get dressed first.

4. Hydrate normally during your training session.

5. When your training session is over, strip off your sweat-soaked clothing quickly, towel off, and weigh yourself.

6. Subtract your the new weight from your previous weight to see how much water you lost.

7. Divide your weight loss by 2.2 to find out how many liters of sweat you lost.

Depending on your exercise level and the weather, you may end up with a net loss of fluid even though you hydrated yourself during the exercise.  This is normal.  Remember that you can sweat faster than you can replace fluids.  If you consumed about one liter per hour and you still lost fluid, you are on the road to heat exhaustion or worse.  It depends on how long you plan to maintain that pace.

What can you do?  Slow down.  Cool down.  Take a break and rehydrate.  Always, always, always rehydrate when you stop to sleep or after a race. And one more "always:" Always maintain electrolyte balance.

Recommendations From American College of Sports Medicine

Based on available evidence, the American College of Sports Medicine makes the following general recommendations on the amount and composition of fluid that should be ingested in preparation for, during, and after exercise or athletic competition:

1. It is recommended that individuals consume a nutritionally balanced diet and drink adequate fluids during the 24-hr period before an event, especially during the period that includes the meal prior to exercise, to promote proper hydration before exercise or competition.
2. It is recommended that individuals drink about 500 ml (about 17 ounces) of fluid about 2 h before exercise to promote adequate hydration and allow time for excretion of excess ingested water.
3. During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace all the water lost through sweating (i.e., body weight loss), or consume the maximal amount that can be tolerated.
4. It is recommended that ingested fluids be cooler than ambient temperature [between 15 degrees and 22 degrees C (59 degrees and 72 degrees F])] and flavored to enhance palatability and promote fluid replacement. Fluids should be readily available and served in containers that allow adequate volumes to be ingested with ease and with minimal interruption of exercise.
5. Addition of proper amounts of carbohydrates and/or electrolytes to a fluid replacement solution is recommended for exercise events of duration greater than 1 h since it does not significantly impair water delivery to the body and may enhance performance. During exercise lasting less than 1 h, there is little evidence of physiological or physical performance differences between consuming a carbohydrate-electrolyte drink and plain water.
6. During intense exercise lasting longer than 1 h, it is recommended that carbohydrates be ingested at a rate of 30-60 g.h(-1) to maintain oxidation of carbohydrates and delay fatigue. This rate of carbohydrate intake can be achieved without compromising fluid delivery by drinking 600-1200 ml.h(-1) of solutions containing 4%-8% carbohydrates (g.100 ml(-1)). The carbohydrates can be sugars (glucose or sucrose) or starch (e.g., maltodextrin).
7. Inclusion of sodium (0.5-0.7 g. per liter of water) in the rehydration solution ingested during exercise lasting longer than 1 h is recommended since it may be advantageous in enhancing palatability, promoting fluid retention, and possibly preventing hyponatremia in certain individuals who drink excessive quantities of fluid. There is little physiological basis for the presence of sodium in an oral rehydration solution for enhancing intestinal water absorption as long as sodium is sufficiently available from the previous meal.

Let's See How Real Products Work

Let's examine four products to see if they meet criteria 6 and 7 of the American College of Sports Medicine recommendations.  The first product will be our baseline product, Gatorade.  This is selected as the baseline because it was the first commercial sports drink and it can be purchased just about anywhere.  The second, ACCELERADE, is one of the newest high tech sports drinks that uses the latest scientific evidence on athletic performance.  The third is three gel packets taken over a one hour period with a liter of water.  And the fourth is the EnduroCaps from Hammer Nutrition for electrolyte replacement only.

Table entries are calories per liter or grams per liter or percent of Minimum Daily Requirements (MDR).

Note 1:  The Hammer product does not meet the recommendations for carbs, but the Endurolyte Capsules are not intended for that purpose.  Hammer nutrition also supplies gels and Sustained Energy for that purpose.

Note 2:  PowerGels supply some electrolytes but not enough to meet the ACSM recommendations.  I usually use PowerGels for an energy boost and rely on my sports drinks for the electolytes.

Complex carbs are typically maltodextrin.

Electrolytes are typically a combination of sodium and potassium.  Hammer Endurolytes also contain calcium, magnesium, and manganese along with vitamin B6.

BCAA is Branched Chain Amino Acids which are used by the body for muscle repair.

C% and E% are vitamins C and E with the percentage of Minimum Daily Requirements (MDR).  These vitamins are anti-oxidants which help reduce the negative affects of high intensity exercise.

WaterTribe Tips

• Know your body.  Do the water loss experiment a few times under various conditions.

• Find a combination of products that works for you.  If you haven't considered these issues before, you can start with the ones in the above table.

• Set your watch to alarm each hour.  Use the hourly alarm to do a mental inventory of your hydration and fuel consumption.

• If you get that horrible sloshing in your stomach, you are drinking too much too fast.  Slow down your pace and your drinking rate.

• You should urinate every couple of hours.  Check the color of your urine especially if conditions are worse than normal or your exertion is higher than normal.

• Use a bladder system for plain water or water with Hammer Caps dissolved into it.

• If you drink a lot of sports drinks, you will reach a state where you just cannot stand the taste anymore.  The same goes for gels.  Always have plain water and regular food available.  If you are in zone 2 and below, you can normally use a lot of regular food.  In zone 3 and above, it becomes difficult to supply your needs with regular food over a long period.

• Be especially careful when your high intensity exertion exceeds the one hour and four hour time frames.  For example, an Elite class Crucible type event.  Ultra events lasting 24 to 72 hours require extreme precision and experience.  Multi day events like a WaterTribe expedition race should be handled in zone 2 or below.

• Get first aid training including heat related illness.

Products to Consider

There are numerous products on the market to provide fluid, electrolytes, and energy.  We all have different needs and palates so it is up to you to select the products that work for you.  The following list is not intended as an endorsement and certainly is not comprehensive.  

CamelBak -- Hydrate or Die® is a registered trademark of CamelBak, a great source for hydration systems.  Their bladders are top notch.  Their packs are good and relatively cheap.  When I'm training, I never put anything but water into a bladder.  As soon as you put a sports drink into one of these bladders, you begin a science experiment that you may not be able to control.  However, for racing it might make sense to use one bladder for water and another for a sports drink.  After the race, toss any bladder that you can't get totally clean.  Another idea is to dissolve Hammer electrolytes in a bladder so you always get the right balance of fluid and electrolytes.  The bladder will be easy to clean since no sugar is contained in the capsules.

Hammer Nutrition -- Gels and electrolyte replacement capsules.  Their capsules contain a blend of several salts and minerals that are designed to be used with plain water or added to your favorite sports drink to enhance the electrolyte replacement process.  These capsules appear to be better than plain salt tablets.  In fact, they may be a good way to make saline instead of using plain salt.  Hammer products are gaining wide spread use among cyclists, triathletes, and adventure racers but they can be hard to find.  Even online they were out of stock as this article was written.  I have not tried them yet, but I plan to experiment soon.

Gatorade -- I used Gatorade as an example in this article because their products are ubiquitous, they are available in liquid or powder form, and they work.  There are other sports drinks on the market so choose one you like.  The great thing about Gatorade is that it does meet the criteria define by ACSM and if you run out of your favorite drink, you can typically find Gatorade at a 7-11 or gas station and such.  The 20 oz size is perfect for regulating and tabulating your consumption in zones 3 and above.

Do not confuse sports drinks with so called energy drinks like Red Bull.  Stay away from faddish energy drinks.

EnduroxR4 and Excellerade -- It has been shown that a ratio of 4 to 1 (carb to protein) has certain beneficial effects beyond the scope of this article.  I use EnduroxR4 everyday after strenuous exercise.  It works for me.  I just started using Accelerade and I have not made a final decision about its effectiveness, but preliminary results are good.   EnduroxR4 and Excellerade are now available from GNC.  

PowerGels used along with plain water are great energy boosters, but notice that they do not meet the ACSM recommendations for electrolytes.  However, if you use Hammer Endurolytes along with PowerGels or HammerGels for energy, you get an excellent match.

Editor's Note:  PowerBar (PowerGels) has recently introduced (7/2004) a new sports drink product.  It looks very promising but I haven't tried it yet.

Wilderness and Travel Medicine, by Eric A. Weiss, M.D. published by Adventure Medical Kits.  This is a great little book about wilderness first aid.  Adventure Medical Kits are great too.

© 2001 Steve Isaac.  All Rights Reserved.

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