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December, 2002
Table of Contents

Surviving When Gods Play
By Steven John Isaac

Make a Hypothermia Kit
By Steven John Isaac

Modify Your Space Blanket
By Steven John Isaac

Dozing Off
By Steven John Isaac

Fueling the Fire
By Steven John Isaac

Hydrate Or Die
By Steven John Isaac

The WaterTribe Kit
By Steven John Isaac

How To Finish a Challenge
By Steven John Isaac

Tow, Tow, Tow Your Boat
By Steven John Isaac








Fueling the Fire

By Steve Isaac (aka Chief)

Customize this article.
Your Age:  


Energy and hydration go hand in hand during long term athletic events like a WaterTribe Challenge or Crucible.  You need to keep your fuel and fluid levels in balance or you cannot produce enough energy to keep moving.  Triathletes call it "bonking" or "hitting the wall."  It's actually easy to keep everything in balance if you know a few facts and keep some simple rules in mind.

If you are going to start exercising, be sure to get an OK from your doctor.  You can also get a stress test that will tell you your actual maximum heart rate.

Your body needs the correct amounts of fat, carbohydrates, protein, electrolytes, and water to keep functioning at an optimum level.  Most of us have more than enough fat to keep us going for days or weeks at a time.  But fat burns in a carbohydrate fire.  If you don't have enough carbs stored or replenished, you will not be able to process your fat and you will bonk.  If you don't have enough water, you will dehydrate and bonk.  If you don't restore depleted electrolytes your nerves and muscles will cease to function, your brain will swell, your lungs will fill with fluid, and you will bonk or die.

Fortunately, it is relatively easy to keep your systems in balance.  It all starts with your heart.

Your body is like an analog computer that indicates how all your systems are doing at any given time by your heart rate.  If you are reasonably fit and your systems are in balance, your heart rate will tell you how many calories you are burning and in what proportion of fat to carbs.  However, the indicator isn't perfect.  It can be thrown off by dehydration, illness, psychological state, and numerous other factors.  But most of the time we can use your heart rate to determine your fuel needs.

Your Heart Rate

Heart Rate Monitors

Purchasing a heart rate monitor is a very good idea.  It will make your training sessions more efficient.  I like the Polar 610, if you can get it, but there are less expensive models that work very well.  Also, the Suunto Advizor watch has a heart monitor, a compass, an altimeter, and a  barometer which is nice during expeditions.

So how fast does your heart beat.  Right now take your pulse and see what your nominal resting heart rate is.  Count the number of beats in 15 seconds and then multiply by four.  This is an indicator of overall fitness.  As you continue your training you should see your resting heart rate come down.  Something in the low 60's is good,  Many very fit people have resting heart rates around 40 beats per minute.

Now let's figure your maximum heart rate.  Subtract your age from 220.  For most people this is a good approximation of your nominal maximum heart rate.  There are more accurate ways to measure it but for now these two numbers will do nicely.

Insert your age into this box and click the button to run the numbers and customize the following table for you.  It is preset to my age but you are probably older :)

At the age of 75 your maximum heart rate is estimated to be:  145

  Zone 1 Zone 2 Zone 3 Zone 4 Zone 5
Mid Zone
% of Max
55% 65% 75% 85% 95%
Beats/Min 79 94 108 123 137
Target Zones Expedition Paddling Crucible Paddling Battle
Cal/Hour 240 420 600 780 1050
204 336 240 195 52
24 63 330 546 945
12 21 30 39 53

Fat contains 9 calories per gram.  One pound of fat contains  454.54 grams or 4091 calories.  That is enough to fuel over 16 hours in Zone 3 for each pound of fat on your body.

Carbohydrates and protein contain 4 calories per gram.

Note that the number of calories burned in each zone does depend on your body weight or what activities you are performing.  But for our purposes these numbers are close enough no matter your weight.  Your heart rate is the only piece of data that you need to determine how many calories of each type that you are consuming.  Your weight and physical conditioning also impacts what zone you will be in for any given activity.  If two people jog three miles at 10 minutes per mile, a 150 pound man in good condition might be in Zone 1 or 2.  Another man weighing 250 pounds just getting off the couch might be in Zone 5.  The calorie counts above would apply to the physically fit man.  They would not apply to the couch potato.  His heart rate is high due to physical exertion AND poor health.  However, a physically fit man weighing 250 pounds might be in Zone 3.  The table above works if you are reasonably fit and in good health.

Most of us have plenty of fat so we don't need to worry about getting enough.  A very fit man weighing 160 pounds and having 6% body fat is carrying 9.6 pounds of fat.  Enough to go about 10 days at 16 hours per day.

But carbohydrates are the key.  Above zone 2 our bodies can store only about two to three hours worth and we are out of gas.  You have to replenish carbs constantly to achieve high performance levels over sustained periods.

The two zones of primary interest to paddlers in the WaterTribe Expedition Races are Zone 1 and Zone 2.  Since Crucible races are over in one day, Zone 3 and Zone 4 can be sustained.  Zone 5 is reserved for battle:  crossing Boca Grande Pass, fighting a tide race, storm conditions.   Take a good look at the table above and notice how easy it is to keep your carbs replenished in zones 1 and 2.  But notice the exponential increase in carb requirements for zones 3, 4, and 5.  It gets increasingly difficult the longer you stay in these zones.  If you are in zones 4 and 5, you might be able to cram enough food into your stomach, but there wouldn't be enough blood available to digest it.  Also, how will your keep your boat moving forward while trying to feed your furnace at such high rates.  And if that isn't enough, there are two limits which your body imposes:

Limit 1:  Your body's systems can only metabolize about 350 calories per hour.

Limit 2:  Your body's systems can only absorb about 1 liter of water per hour.

Zone 1 -- An Afternoon Paddle

Most reasonably fit kayakers are going to be in Zone 1 most of the time.  Typical trips are leisurely with lots of time spent on a beach.  WaterTribe Challengers can find themselves in this zone when the wind and tide make paddling easier.  Always take advantage of this zone to eat solid food because your blood supply is not needed for your muscles and can be diverted to your stomach. This is a recovery zone.  Training in this zone is beneficial and puts very little stress on your joints and your body's systems.  If you "need to get in shape," start in Zone 1 with walking or water exercises.  

Zone 2 -- Burning Fat

Notice that Zone 2 burns more fat per hour than any other zone.  If you are trying to lose weight and get in shape, you want to spend a lot of time in Zone 2.  Your body is training itself to convert fat to energy.  Training in this zone will increase the number of mitochondria in each cell.  Efficiency in all zones will benefit.  If you don't replace the fat you are burning by snacking, you will lose weight.  For ultra endurance sports lasting several days, you want to get your body fat to about 12% but not much less than that.

Notice that you will need about 63 calories per hour of carbohydrates and another 20 calories per hour of protein.  That translates to about 1/2 of a 20 oz. bottle of Gatorade per hour along with a "chew" of low fat jerky.

During an expedition race like the Everglades or Okefenokee or Lake Michigan most of your paddling time should be in Zone 2.  You can keep this up all day long.

I find that training in Zone 2 is difficult.  Running always gets me into Zone 3 after a couple of miles.  The only forms of training that keeps me in Zone 2 is bicycling, swimming, and paddling.

Zone 3 -- Cardiovascular Fitness

This is the aerobic training zone. You get the most training benefit for cardiovascular fitness in Zone 3.  You still burn lots of fat but carbohydrates are your main source of energy in Zone 3.  

You will need about 330 calories per hour of carbs, but only 30 calories per hour of protein.  That's about one 20 oz. bottle of Gatorade every 20 minutes along with our chew of jerky each hour.  Now that's a lot of Gatorade.  Instead, you might want to start using PowerGel or Gu or some other carb source to supplement your sports drink.

Zone 3 is sustainable for days if you can keep up with your bodies demands for carbs, protein, electrolytes, and water.  This takes planning and practice.  It isn't easy to keep up with this type of demand hour after hour and day after day.  World class adventure racers and ultra runners and cyclists do it all the time.

Zone 4 -- Threshold of Super Fitness

Calories burned from fat goes way down but training in this zone is essential for truly outstanding physical fitness.  You will transition from aerobic training to anaerobic training.  Your muscles will not be able to get enough oxygen.  You can continue but you will feel the "burn" from the build up of lactic acid.  Endorphins will be produced that give you the "runner's high" and your body will begin to get really efficient.

Even if you are very physically fit, you may find it difficult to stay in Zone 4 longer than about one hour.  I like to train in Zone 4 two days per week for one hour each day.

Zone 5 -- Battle

One of the best reasons to wear a heart rate monitor during your race is to help you stay out of this zone.  Typically it is difficult to even sip water from a CamelBak when you are in this zone because your oxygen demands are so high you cannot afford to interrupt your breathing.  Forget opening a gel pack or a bottle of Gatorade.  All your fuel has to come from stored sources in the body.  This zone cannot be sustained for longer than a few minutes.  If you stay in this zone until exhausted, you may not recover for a long time which could force you to quit a Challenge.  Reserve this zone for those moments when everything is on the line. Perhaps a sprint to the finish or getting through a tough section of water.

Fueling the Zone

The following table provides some guidelines for sources of carbs and protein that will fuel one hour in each zone.  Notice that in Zone 3 you can get your fuel with 3 PowerGels or 6 apples.  Try eating six apples in an hour and you will see why PowerGels are so important.  The flip side is that PowerGels taste pretty good at first, but I guarantee that the 15th PowerGel of the day will go down hard.  No matter what you decide to eat, avoid fat as much as possible.  Fat is harder to digest and will divert too much blood to the stomach.

  Zone 1 Zone 2 Zone 3 Zone 4 Zone 5
24 63 330 546 945
Carbs 4 oz Gatorade
1/2 Apple
1/2 Orange
1/2 PowerGel
8 oz. Gatorade
1/2 Banana
3 PowerGels
50 oz Gatorade
3 Apples
3 Oranges
3 Bananas
5 PowerGels

No time for 
Protein 1 oz jerky 2 oz jerky 3 oz jerky NA NA
Water 1 Liter 1 Liter 1 Liter 1 Liter NA
  If you have that horrible "sloshing" in your stomach, you are 
drinking too fast.  If you aren't urinating about every 2 hours or 
so you aren't drinking enough.
No Time
to eat or

Notice the NAs in zones 4 and 5.  When you are working at these levels, you cannot afford to put protein in your stomach.  There won't be enough blood available to digest it.  Instead it will make you sick or cause cramps.  Also, in zone 5 all your carbs must come from carbs stored in the muscle.  Stay out of zone 5 except for very short periods of time.

The table recommends that you consume about 1 liter of water per hour in all zones.  This may be more than you need in the lower zones and not enough in the higher zones.  But this is about the maximum your body can process.  By consuming more than you need in lower zones you will be well hydrated if you suddenly need to boost your energy levels.

Notice how difficult it is to fuel the body starting in zone 3 and getting almost impossible in zone 4 and totally impossible in zone 5.  On the other hand, zones 1 and 2 are easy to fuel.  What does that tell you over a 12 to 16 hour day?  That's right -- stay in zone 2 as much as possible.

The key is to be physically fit so that you can keep your boat going at hull speed while your heart stays in zone 2 or zone 3.  So buy a heart rate monitor and wear it next time you go paddling.  

Hydrate or Die

Hydration will be covered in more detail in another article.  For now a couple of simple rules and a warning will suffice.

Your body can only process about one liter of water per hour.  If your body needs more than that due to metabolism and sweat, you can begin to dehydrate even if you are drinking a lot of water.  

  • respiratory distress
  • nauseated
  • disoriented
  • pink frothy sputum

In addition  to water you must replace electrolytes or you can get into a dangerous condition know as hyponatremia or "water intoxication" in layman's terms.  This is a build up of excess fluid in the brain and lungs.  The critical point for this condition is high intensity exercise that lasts for roughly 4 hours or more combined with inadequate electrolytes.  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.

  Zone 1 Zone 2 Zone 3 Zone 4 Zone 5
Gatorade or 
Per Hour
10 oz. 20 oz. 40 oz. 40 oz. NA
Per Hour

1/2 Liter

1 Liter

      Assumes you also use one or more 
PowerGels per hour.

If duration is more than 3 hours also use high salt snacks such as jerky, pretzels, chips.  In extreme conditions supplement with electrolyte pills (salt tablets).

An Eating Plan for the Day

This plan assumes you want to travel fast and light.  You don't want to wash dishes and you want to crash as soon as possible because you are already sleep deprived.  This is the adventure racer's plan for an 8 to 12 day event.


  • Perk up some real coffee.  Drink half the pot and put the rest in a good thermos bottle.  When you are done, rinse the coffee pot out real good.  Washing isn't necessary.

  • Eat a high carb and moderate protein breakfast bar.  Some fat is OK but try to keep it down.  I like HarvestBars and ProteinPlus, both from PowerBar.  A  HarvestBar and a ProteinPlus bar while breaking camp and drinking coffee is about right for me.  Choose something you like and works for you.  Even Pop Tarts work.

During the Day:

  • Consume high carb snacks with limited protein throughout the day.  Carb to protein ratio should not exceed 4 to 1.  Keep the fat content down as much as possible. Check the table toward the top of the article for the amount of calories to consume.

  • Stay in zone 2 as much as possible.  Zone 3 might be necessary when crossing a pass or fighting a current.  Zones 4 and 5 should be avoided if possible.  However, have PowerGels handy just in case.

  • Use a combination of PowerGels, apples, oranges, bananas, chips (low fat), pretzels, and limited jerky (low fat) for snacking during the day.  Unless you can stay in zones 1 and 2, forget traditional gorp, nuts, chocolate due to too much fat.

  • Know your heart rate zone and pay attention to the tables on carbs and protein requirements.  Remember zone 2 is your preferred zone for long days in succession.

  • Note the hydration table and make sure your hydration needs according to your zone are met.

Evening Meal:

  • Your evening meal might come at 03:00 but you must still view it as a dinner and it is the most important meal of the day.  Your body had been pushed to the limit and this meal will help it repair itself and get ready for the next day.  You will be somewhat dehydrated at the end of the day even if you stayed on your fluid replacement program.  This is the time to fully hydrate your body so you are ready for the next day.

  • As soon as your kayak is anchored safely mix up a 16 oz. drink of EnduroxR4.  This is a recovery drink that will go a long way toward keeping your body well fueled and ready for the next day.  

  • Keep drinking water as you setup camp until your urine is clear.

  • Boil enough water for a freeze dried meal and any other use.  Perhaps an herb tea to help you sleep.

  • A freeze dried meal that serves 2 to 4 people is about right for one long distance racer.  Get the kind that has its own mixing bag so there is no cleanup.

  • Have as much desert and fat as you want.  Watch out for chocolate or other foods that might keep you from sleeping soundly.

  • Take a pee bottle into your hammock or tent.

A Racing Example

While writing this article I put these principles to work in a one-day adventure race here in Florida.  Preparation started the night before the race with a large carbo loaded dinner and plenty of water.  At 05:00 I had coffee and Pop Tarts (hey, I was in a hotel room).  At 06:00 I had a banana which was my last solid food before the race.  I drank orange juice, a 16 oz. bottle of water and a 20 oz. bottle of Gatorade over the next two hours leading up to the start at 08:00.  I urinated about 3 times during this period the last about 5 minutes before the race.  Just before the race started I took my first PowerGel with a few gulps from my hydration pack.  I was very well hydrated and fueled at the start.

I completed the race in 6 hours while wearing a heart rate monitor.  I spent about 1 hour in zone 2, 3 hours in zone 3, 1 hour in zone 4 and 1 hour in zone 5.  Of course these zones were mixed up so my hour in zone 5 was not all at once.  During the race I consumed 80 ounces of Gatorade, 6 PowerGels, and 2.5 liters of water.  I urinated a small amount 2 times.

During July in Florida's summer heat and humidity you are always going to sweat faster than you can replace fluids.  So at the end of the race I was a bit dehydrated, but I felt pretty good.  

Contrast my fueling needs with the winners and you will see why it is important to get in shape at a much lower weight.  The winners did the race in roughly 3 hours and 20 minutes.  Their heart rates were lower than mine so they didn't need as much fuel.  Instead of carrying all that extra water, they did the first section with one or two bottles of Gatorade.  When they switched to the bike, they probably had another full bottle.  Add a couple of PowerGels and they can do the whole race.  Since their load is less they need less fuel and they are on a winning spiral.

The moral of the story is to get in the best shape possible.  But that is another article.

Leave No Trace

PowerGels and their competitors are great products but they have one big problem.  The convenient single serving packets have a tear off top.  During triathlons and adventure races you see the tops and empty packets dropped along the trail.  I hope the WaterTribe will be more careful and carry out all empty packets and tear-off tops.

I carry a small Ziplock bag to put empty packets into so they won't make everything else sticky.  When you reach civilization, dump your garbage in an approved dumpster.  If you are in a one-day event like the Crucible and  you know that your calorie demands are going to be very high, you can use multiple serving PowerGel packets that reduce the problem because they don't have a tear off top.  You can also load gels into non-disposable flasks designed for the purpose.  I don't recommend these flasks for multi day events due to sanitation issues.  However, they work well for one-day events because you can put the flasks into the dishwasher after the race.


The heart rate information contained in this article is adapted from The Heart Rate Monitor Book by Sally Edwards and Sally Reed and published by Velo Press.  Other sources too numerous to mention have been digested over the years.  

Note that I am not a doctor or a nutritionist or any other recognized expert in the field.  The opinions expressed here represent my study of the issues over the years.  However, they are supported by my own empirical evidence.

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

PowerBar -- Again these products are ubiquitous and they work.  Many other sports bars and gels are on the market so experiment and find one you like.  

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 haven't used Excellerade yet due to the lack of retail outlets but I hope to try it soon.  EnduroxR4 is available from GNC.  

CamelBak -- A great source for hydration systems.  Their bladders are top notch.  Their packs are good and relatively cheap.

© 2001 Steve Isaac



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