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OVERVIEW

• Water is the most critical nutrient, not only for survival, but also for your performance.
   
• Avoid Heat Related Problems: wear a hat, light colors, rest in the heat of the day, and drink frequently, see Table 5. Treatment of Dehydration.
   
• Hidden water-- the water should be in your bottle, not in your food, see Table 6. Water Content of Trail Foods
   
• Excess salt can cause retention of water and burden kidneys, see Table 7. Salt Content of Trail Foods.
   
• To avoid excess salt: avoid processed foods, buy reduced salt products, combine high salt foods with low salt foods. Do NOT take salt tablets.

THE COOLANT: WATER!

Water is without debate, the most critical nutrient for your performance and your survival.. What you need when energy flags and your head spins is WATER, WATER, WATER!

How much water do I need each day?

It depends on the temperature, on how hard you're working, on your physiological state--too many variables to give a pat answer. BUT you can know if you're getting enough water. You should need to urinate more than three times a day, and your urine should be pale yellow-to-clear, NOT dark yellow. If in doubt, drink some more. Don't wait until you're thirsty, or you're past the point of "impaired performance." For a ballpark estimate, figure at least 3 quarts/person/day.

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HYDRATION TIPS

• Drink at least 3 quarts of water/day; more in hot, dry climates.
   
• If you don't need a "potty stop" in the morning before your first cup of coffee, you're dehydrated. DRINK!
   
• If you drink a quart of fluid and don't see any of it appearing out the other end, you're not drinking enough. DRINK!
   
• You'll know when you've had enough by the color of your urine. It should be clear amber, not cloudy dark yellow.
   
• Dilute sports drinks slightly--(1/4 Cup mix in 3 Cups water); the sports drinks are formulated for runners, high in salt and sugar for a quick recharge. You need a slow, steady dose.

 Why is water so important?

#1) It's the SOLVENT and reactant for the chemical reactions that keep your muscles moving and your mind alert. Without sufficient water, you dehydrate and collapse.

#2) Water is the COOLANT that carries away the excess heat you generate working so you can maintain the ideal "98.6^oF" (or whatever is normal for your body temperature). In short, it does for your body what the radiator does for your car engine. If you can't evaporate off the heat fast enough or are dehydrated, you collapse (heat stroke or heat exhaustion, respectively). In this situation, water outside of the body is almost as important as water inside the body. In very hot climates, make sure you douse your head and torso at every opportunity; wear a wet bandana around your neck. The water outside your body will help as well as the water inside your body to conduct the excess heat away from your body.

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What do I do in case of dehydration or heat exhaustion?

In either case, the victim will lose consciousness if the dehydration or exhaustion is severe. Cool their body with wet cloths and fanning (pour your water bottle on them, if necessary, especially on the chest and neck). When the victim is conscious, encourage them to sip water and rest in the shade. Don't allow them to get up until they have consumed at least a quart of water. (Their spinning head should tell them if they haven't had enough yet--drink more.) This is the most common ailment of summer travellers in the Great Southwest. Thankfully, it's easily remedied if you're carrying sufficient water. Once rehydrated, you can go on and finish the 20 miles you set as your goal, but go gently.

Better, however, is an ounce of prevention.

• Don't hike in the heat of the day. Get started before the sun comes up. Find a quiet place by 1:00 p.m. and rest for 2 hours.
   
• Wear a hat with a brim; wear white colors to reflect the sun's heat.
   
• Wear plenty of sunblock if you choose to expose your skin.
   
• Relax your muscles as you walk. Going downhill? Shuffle/duck walk, using different sets of muscles on the outside and inside of your leg, rather the the relentless pound, pound, pound of the normal downhill stride. Going uphill? Zigzag, again using different sets of muscles.

MIXED MESSAGES

Now that you're properly convinced that water is critical for your well-being, performance and survival, I'm going to flip the message. When it comes to food, leave the water behind. Get the water INTO your water bottle, but OUT of your food bag.

 What is the most efficient food --the food that weighs the least but provides the most calories?

As you can see by comparing the values in Table 6, the best you can do is 8.6 calories/gram (vegetable/olive oil). If you carry foods that are not dried, the values can be less than 1.0. For a 50-35-15 diet, try to keep close to the 5 Cal/g, with less than 10% water in the foods you select. Thus, you might choose Pringles over Pretzels, banana chips instead of dried apricots, gingersnaps rather than fig bars. The lower % water, the less unnecessary weight you carry. The higher the caloric density, the more efficient the food weight you carry. Even foods that you consider "dry", like spaghetti or bagels, are likely to carry more water than you expect. Water content and caloric density of Trail Foods are listed in Table 6. The higher the density, the better. It may help you decide what to take, and what to leave home next time you travel.

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DEHYDRATION TIPS

   To reduce water weight even without a food dehydrator:

• Buy dried onions, fruits, mushrooms, soups, etc. readily available at grocery stores.
   
• Extend soups with your own dried vegetables (and reduce salt concentration).
   
• Bake thin-sliced bagels/breads for 10 minutes at 350^oF to cut the water weight in half.
   
• Make fruit leather in any conventional oven (See Saving Fuel).

*My home-dehydrated fruits and vegetables are dried to the crispy stage, so they contain less than 10% water. Less water means less opportunity for bacterial/fungal activity, and lighter weight for me to carry.

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 SALT

What happens if I don't get enough salt?

Not likely, if you are eating enough calories to sustain you day after day. (see Table 7.) However, if you drink coffee/caffeinated beverages rather than water/juice, the diuretic affect may induce dehydration and electrolyte depletion. In this case, rehydrate with a quart of dilute Gatorade or another electrolyte-supplying drink. (To get optimum absorption, make a 5% sugar solution, by mixing 2 scoops (4 T) Gatorade per 3 cups water.) If you're thirsty, more caffeine will only make you thirstier.

If you are taking medications, read the labels carefully. Many induce electrolyte loss and therefore you would need to choose moderate- to high-salt foods/drinks, rather than a strictly low salt diet.

 What happens if I get too much salt?

Much more likely to have long- and short-term consequences, compromising performance due to the strain of carrying excessive weight, loss of water, fatigue, and for some, increasing their risk of heart disease.

 Water follows Salt:

Normally, when too much salt is consumed, a healthy kidney has to work harder to correct the salt imbalance (get rid of the excess salt). When you consume excess salt, you must absorb more water so that you can "flush" out that salt. Remember from high school biology class, osmosis is the movement of water from a region of low salt concentration to high salt concentration. If you eat salt, then water follows that salt. Thus, it follows that a steady diet of salty foods increases the blood volume, requiring that the heart work harder. When you're hiking, the last thing in the world you would want is to pump "diluted" blood, rather than pumping the oxygen-rich blood your starving muscles demand. So the kidney works harder to flush out the salt, the heart works harder to deliver oxygen to the muscles, and YOU work harder because you have to transport and purify all the water necessary to keep your body reasonably balanced. Would you deliberately choose to carry extra weight along the trail? That's what you are doing when you eat excess salt.
 
 

But don't I need more salt when I'm exercising?

Simply stated, "Salt in" should equal "salt out", i.e., you only need to replace the salt that is lost. Most salt is lost through urine and perspiration. Under normal conditions, the human body requires only 200 mg sodium ("salt" = sodium chloride) to maintain balance. The Daily Reference Value (or more familiar, RDA), based on a 2000 Calorie diet, is 2400 mg sodium, ten times more than you "require", but enough to make your food taste good. At that, most of us still eat twice the RDA/DRV in a day, so we consume more than 10 times what we need. Thus, even if you increased your perspiration volume and urinary output tenfold on the trail, you would still be getting enough sodium, given the typical American diet. (Depending on acclimitization, approximately 1000 mg (1/2 teaspoon) sodium are lost in one quart of perspiration. Therefore if your weight decreases by 6 pounds in the course of a day of strenuous hiking, you have likely perspired off 3 quarts --"A pint's a pound the world around". You could justify consuming an extra 3000 mg sodium that day.)

I really sweat a lot. Don't I need salt tablets?

Not if you are eating over the course of the day. Even food as "unsalty" as a fig bar contains 45 mg sodium. Do you snack on jerky, or trail mix with salted nuts? Do you dine on instant soups or prepackaged meals? Do you drink a sports drink such as Gatorade? A salt tablet contains 500 mg sodium, so a handful of trail mix or a helping of instant soup provides the equivalent of one or two salt tablets. (Compare values in Table 7.) As long as you are eating sufficient calories to sustain your exercise (approx. 3000-4000 Cal), it is not necessary to take a salt tablet. Salt tablets would only be necessary if you were sweating profusely (over 4 quarts/day) and drinking only water (not eating food or drinking other beverages). [Note: caffeinated beverages do not count as "drinks". Caffeine is a diuretic, so you lose almost as much fluid as you gain by drinking the beverage. Highly sugared beverages also "draw water" out of the body.]

With all that said, for any PCT hikers that are trailing across the Mojave desert or the Oregon lava beds in late spring or summer, you should be especially wary of salt depletion. You of all hikers will likely be losing quarts of sweat each day and you may not be consuming adequate food. Unless you are genetically predisposed to hypertension, go ahead and eat those high salt soups/pretzels! Dehydration due to excessive sweating and inadequate fluid intake can be life-threatening, but if you drink enough water so that what goes in comes out, you avoid the danger of dehydration.

What is the most reasonable way to reduce my salt intake?

If you are presently consuming over 4000 mg/day and you think your intake is excessive, here are some suggestions for moderating your salt intake.

1. Wean yourself gradually. Do you use salt in cooking and salt your food again at the table? Try eliminating one of these "exposures". (Removing the salt shaker from the table is the most effective, but meets with the most resistance with unconvinced consumers.) For example, fry eggs and potatoes without adding salt. Let each individual salt his/her portion at the table. Count shakes, and work from 6 down to 3 in the course of three weeks.

Cut the salt in half in your favorite recipes--you'll never miss it.

Same idea: Use 1/2 the spice packet with a package of Ramen noodles. To serve twice as many people, use three times as many noodles with the Macaroni & Cheese, adding sauted onions, mushrooms, and peppers for added flavor.

2. Select foods from the low salt column to balance out the foods you select from the high salt column. For instance, double the amount of water added to soup then add 1 cup additional vegetables. Vegetables are low salt. The soup then serves two, rather than one. Salt is cut in half. Or balance the high salt soup with a low salt cracker. With high salt processed/canned meats, eat low salt cereals/grains (like yeast breads or pasta) and vegetables.

3. Read labels! Compare brands. Buy reduced salt products. Many manufacturers are aware that there is a growing market for low salt alternatives. Note that natural cheeses are much lower in salt than processed cheeses. This is true for processed meats (bologna, sausage, pastrami, etc.), canned products and prepackaged meals. Eat all the dried fruits and vegetables you want. They are naturally low salt unless processed with added salt.

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Value in ( ) is mg sodium/serving. 1 teaspoon table salt = 2300 mg sodium, the RDA
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