Hydration

[Rick M]

Twenty or so years ago I saw something about survival being 4 minutes without air, 4 hours without shelter, 4 days without water and 4weeks without food. Since summer is approaching, I was wondering what people do to hydrate themselves both before and during their hikes.

Before hand, I'll drink a sugared soda and an equal amount of water; if it's a search at night I'll drink one with caffeine.

During the hike I usually drink lots of water and occasionally mix in some Hydrolyte or Gatorade diluted 50% with more water to make it tolerable during the hike. If I'm with certain "friends" I'll drop my apple core in my water bottle to keep them from asking me for my water...it seems to work.

In the winter for a day I usually carry two liters water for a day hike and three for an overnighter if I'm not going to have access to a steam or spring or snow. In the summer, I'll carry 3-6 liters depending again on conditions (I once consumed six liters in one summer morning hiking 12 miles in July in the Fish Creek Mountains...116 degrees, DON'T TRY THIS!

On a recent search, a medical type person was concerned about all the water I was drinking but I think the salt in my snacks and the alternating electrolyte solutions should work as I usually do ok (always outlasted searchers in Death Valley...but proper clotheing for conditions help too).

Any thoughts ideas comments on what you do/use or how I can improve what I do.

[Bivouac]

Rick M.

My only comment on hydration is from a perspective of ultra endurance events. . . . The rule is that any sugar consumed before absolutely necessary disrupts proper hydration.
If this occurs. . . then sugar doesn't absorb maximally when consumed.

Hydration first. . .sugar a distant second. Probably not critical in low calorie burning situations but just thought i would mention it.

[FIGHT ON]

Rick.
I drink water on the way to the trailhead. I also carry and drink more water then I need. I don't mind the extra weight because it sure feels better than being dehydrated. I like being able to drink as much as I want and not have to wonder if I will have enough for the rest of the hike. Also if someone else I am with runs out they can have it. I don't take caffeine because it raises your heart rate. I like to know that because it is going faster it's because of my hiking and not because I took a drug. I heard that carbonated drinks do something to the cells in your body. When you drink carbonated water, there is an imbalance of less water outside of the cells. so the body takes out water from the cells to balance the water content inside and outside of the cells. so therefore your cells have less water after drinking carbonation. So I avoid them too. Boring I guess but I like to keep as close in touch with what's really going on in my body as I can.

[Ellen]

Howdy Rick,

During endurance exercise lasting up to 24 hours, your primary needs are water, carbohydrate, and sodium. Dehydration can happen sooner than muscle glycogen depletion, so ultimately water is the key nutrient for both health and performance.

I like Gatorade and carry at least 2 liters in the winter and at least 3 liters in the summer for day hikes. In the summer, I use Gatorade Endurance due to the higher sodium content (I'm a salty sweater) and in the winter I use regular Gatorade.

I've worked with numerous endurance and ultra-endurance athletes (runner, cyclists, triathletes and hikers). Most of them have tried different sports drinks and found one that "works' for them. Some athletes drink water and carry carbohydrate and sodium sources (e.g. higher sodium sports gels, pretzels, etc.)

Research with ultra-endurance athletes indicates that we can "burn" up to 1 gram of carbohydrate per kg per hour. During warm hikes, I generally go through one pint or more of Gatorade an hour and one gel an hour. This gives me about 40 grams of carbohydrate, well within what I can burn. Liquid and solid carbohydrates are equally effective -- each has advantages and drawbacks.

The optimum carbohydrate concentration for a sports drink is 4 to 8%. More concentrated drinks are absorbed more slowly, as Bivouac pointed out. This not only slows the water getting into your blood, but can also cause gut distress. Soft drinks and fruit juices have 12 to 15% carbohydrate. Since you're drinking the same amount of water after the soda, you've effectively reduced the carbohydrate content to acceptable amounts.

Some ultra-endurance athletes (Ironman triathletes, Tour de France cyclists) use products that are 18-24% carbohydrate such as CarboPro and InfiniT. The rationale is that they can carry alot of calories in their feed bottle. However, they also carry a water bottle and obtain water and/or sports drinks at aid stations. They cosnume a certain portion of the bottle each hour and dilute it with water to meet their carbohydrate requirements.

Hypontremia (low blood sodium) is a concern during ultra-endurance exercise lasting over four hours. A continous decrease in blood sodium causes rapid entry of water into the brain. This causes brain swelling (cerebral edema) and a series of neurological responses (confusion, seizure, coma) that can end in death from brainstem rupture.

Hyponatremia is primarily caused by consuming an amount of fluid that exceeds sweat and urinary water losses. The most likely explanation for exercise-associated hyponatremia is that excessive drinking reduces the plasma sodium concentration.

In endurance events such as the marathon, symptomatic hyponatremia is more likely to occur in smaller individuals who run slowly, sweat less, and drink excessively before, during, and after the race.

During prolonged endurance exercise such as an Ironman triathlon, high sweat rates and a high sweat sodium concentration (“salty sweat”) can also contribute to hyponatremia. Large sweat sodium losses confer a greater risk of developing hyponatremia because less fluid intake is required to produce dangerously low blood sodium levels.

Now to bring this back to hiking...
Hyponatremia has occured in individuals hiking the Grand Canyon. To my knowledge, it isn't common in hiking otherwise. I think some people hiking the canyon over-drink on the way down when they aren't sweating much and so dilute their sodium level.

Regarding your situation....
You've probably been fine because your sweat rate has matched or exceded your fluid intake. Consuming salty snacks or higher sodium sports drinks helps to maintain blood sodium levels as well.

I encourage athletes in endurance events (including hikers) to measure their sweat rates during different environmental conditions. That is the only way to know how much to drink. If an athlete gains weight after a workout, he or she is over-drinking. If an athlete loses over 2% of body weight during a workout, he or she is getting dehydrated and needs to drink more.

OK -- it's 5 PM now and I'm off the clock Hope this helps.

Miles of smiles,
Ellen

[Rick M]

Gee Ellen, that's awesome!
On the whole, I usually weigh less (anywhere from 1-4 pounds) after a search depending on the mission and time of year and if I stop with the rest of the team afterwards to eat. I always attributed it to calories consumed and given off as CO2 and H2O. It looks like much of it might be water loss since most searches last less than 12 hours. I tend not to drink as much as I probably should during a search because of the concern of running out of water and then maybe finding a dehydrated or heat stroke person we're searching for or for a fellow search who has run out of water (I always like to have 1 liter with me at all times that doesn't get used). I don't really like salty sport drinks and so always try to supplement with salted nuts, chips, or other foods (and juices that I dilute).

I also like what I just read in your book Eating for Endurance:

...In addition to aiding fluid absorption during exercise, the sodium in sports drinks encourages fluid intake because it makes the drink taste better.
Sports drinks containing sodium can promote rehydration after exercise. The sodium helps to maintain your thirst and keeps you drinking while it delays urine production. This combination promotes rapid rehydration and enhances your recovery. Drinking plain water eliminates your thirst so that you stop drinking, and urine production is stimulated. This sequence delays rehydration and can hinder your recovery.

p. 115

Recovery is important in search and rescue because just when you come down the mountain from your assignment you might be asked to go back up again to another area.

I hope it's ok to quote from your book, I just got it and it's the first thing I've ever read about "nutrition" and such...all I can say is I love root beer and pizza supremes . I just need to find a sports drink whose taste I like...never have found a beer that I liked...they all taste like old stump water to me.

Thanks again. I had inquired of another RD and nutritionist about doing something for us mountain rescue types for food and fluids and looks like you have done that with this post and the one for food by LipBiter. I owe you one!

[HikeUp]

Ellen, your posts are extremely informative - thanks.

Not quite sure how to ask this, but is hyponatremia a more serious condition that dehydration? I'm sure it's not a clear cut answer, but if you had a choice of drinking too much (leading to hyponatremia) vs. not drinking enough (leading to dehydration) which is the least risky choice on a strenuous hike?

If I try to sip water/gatorade every 10 minutes or so (or on some regular schedule) I tend to hit a point where I just don't feel like I can drink any more...my stomach says "I'm full already!"...even if I am sweating a decent amount on a summer time hike. I tend to lose a pound or two or more on such days and wonder if I need to force down more water/gatorade or if erring on the dehydrated side of things is ok.

[Perry]

I mix my own sports drink and add 1.5 teaspoons salt per gallon. But I think I lose salt at a faster rate than most people, so others may be able to get by on less. The thing about hyponatremia is that a person's condition can rapidly deteriorate after drinking a bottle of water. And it's deceptive if you aren't familiar with the effects.

[magikwalt]

As a young skinny Marine I went with a water salt mixture for hydration and a massive bag of M&M Peanuts. As I've gotten older and fatter I've taken a line much closer to Ellen's. Give me Gatoraide Endurance, salted peanuts and either an apple or an orange. I don't dilute the Gatoraide.

Everytime I've played with the formula on long hikes or high heat (sometimes both together) I have paid for it with muscle cramps and crummy finishes to what should have been a fun hike.

[FIGHT ON]

So when you pee, if it is clear are you drinking too much. Or if it is really yellow are you not drinking enough?

[Perry]

Depends on B vitamins. I would just drink plenty, eat plenty of carbos, and get plenty of salt.