Hydration V Dehydration.

[P36]

Who needs the Comedy Channel, anyway? Sorry if I wasn't clear in my original post. Yes, I drank a ton of water that day. It was a "learning" experience. Seriously, it was.

Who knew you could kill yourself by drinking too much water? Common sense would say that you would just empty it out the other end, right. So if you didn't have to go, you must be REALLY dehydrated! Live and learn.

[NousDefionsDoc]

"No-P36" LOL

[VMI_Marine]

Originally posted by ccrn
In my flield we consider the general population to be dehydrated overall. People wince when I suggest to them they need to drink 6-8 large glasses of water a day. They prefer to spend money on mountian dew, jolt cola, and 44oz big gulps full of soda.

Dehydration can cause lethargy, difficulty concentrating, confusion, even coma and death. For the average individual not in crisis this is manifested by decreased performance across the board. Students should take note.

The one semester in college where I felt truly awake and alert during every class, I was taking a PT-intensive OCS prep course and bringing a 32 oz bottle of fluid with me to every class. After that, I stopped going for the coffee and soda on road trips.

The gist that I am getting from this thread with regards to overhydration is that under normal circumstances it is not a threat to Joe Citizen. Those of us in the "business", who spend a lot of time outside of normal circumstances, need to monitor our hydration and food intake because the stress we place on our bodies interferes with the kidneys' ability to process and excrete the excess fluid. Is the lieutenant on track here, or am I wandering with the map upside-down again?

[18C/GS 0602]

Originally posted by VMI_Marine
Those of us in the "business", who spend a lot of time outside of normal circumstances, need to monitor our hydration and food intake because the stress we place on our bodies interferes with the kidneys' ability to process and excrete the excess fluid. Is the lieutenant on track here, or am I wandering with the map upside-down again?

While there are reports of extreme exercise causing decreased renal function in the medical literature I think that the majority of cases of exercise induced hyponatremia are due to environmental factors i.e. someone losing a large amount of sodium in their sweat but only replacing it with water/sports drinks and no oral rehydration salts (ORS) or food. I think there are two reasons for this. First many extreme athletes are very aware of dehydration, and how it can cause a decrease in performance, but not aware about how over hydration can also cause problems. The second part is that sports drinks are not enough by themselves- when a large amount of sodium is lost you need ORS or food, which have much higher content of sodium than sports drinks. It boils down to someone losing more sodium than they are replacing, rather than exercise causing the kidney not to function properly.

[ccrn]

QUOTE]Originally posted by VMI_Marine
Is the lieutenant on track here, or am I wandering with the map upside-down again? [/QUOTE]


Sir, its more like this:

Rather than renal function this is more a matter of osmosis ie the shifting of water in the body, between inside and outside the cell.

There is a saying in medicine that where salt is water will follow. Outside the cell is where sodium likes to live, inside the cell is where potassium lives. When sodium is low outside the cell water tends to shift from the outside to the inside ie overhydration and hyponatremia(attracted to the potassium). This also causes cells to expand causing the neuro symptoms of hyponatremia. When sodium is high outside the cell ie dehydration this causes water to shift to the outside (attracted to the sodium) of the cell shrinking it. When one salt is concentrated more than the other the water will go to it.

If the cell can be thought of as a "battery"of sorts (depolarization)this can explain why we dont function well ie not contracting optimaly or conducting correctly when poorly hydrated. If a neuron doesnt have enough water in it, or too much it wont "conduct" correctly and therefore difficulty concentrating, confusion, lethargy etc.

My battery analogy isnt a very good one but I think it effective when considering hydration. If the battery is too full it can expand causing damage while to low it cant conduct.

To summarize if the cell is swollen with water (overhydration;hyponatremia) it cant funtion properly. If the cell doesnt have enough water in it (dehydration) it also cant function properly.

Respectfully-

ccrn

[Sacamuelas]

As much as a 5 to 10 lb weight loss has been recorded in athletes in a period of 1 hour during endurance athletic events under hot and humid conditions. Essentially all of this weight loss results from the loss of sweat. Loss of enough sweat to decrease body weight only 3 % can significantly diminish a person’s performance, and a 5 to 10 % rapid decrease in weight can often be very serious, leading to muscle cramps, nausea, and other effects. Therefore, it is essential to replace fluid as it is lost.

You need to provide replacement of Salt AND Potassium. Sweat contains a large amount of salt, for which reason it has long been stated that all athletes should take salt tablets when performing exercise on hot humid days. Unfortunately, overuse of salt tablets has often done as much harm as good. Furthermore, if an athlete becomes acclimatized to the heat by progressive increase in athletic exposure over a period of 1 to 2 weeks rather than performing maximal athletic feats on the first day, the sweat glands also become acclimatized, so that the amount of salt lost in sweat is only a small fraction of that prior to acclimatization. This sweat gland acclimatization results mainly from increased aldosterone secretion by the adrenal cortex. The aldosterone in turn has direct effects on the sweat glands, increasing the reabsorbtion of NaCl (salt) from the sweat before it issues forth from the sweat gland tubules onto the surface of the skin. Once the athlete is acclimatized, only rarely do salt supplements need to be considered during athletic events.

On the other hand, recent experience by military units exposed to heavy exercise in the desert has demonstrated still another electrolyte problem- the problem of potassium loss. Potassium loss results partly from the increased secretion of aldosterone during heat acclimatization, which increases the loss of potassium in the urine as well as in the sweat. As a consequence of these findings, some of the newer supplemental fluids for athletes and soldiers are beginning to contain properly proportioned amounts of potassium and NaCl.

Note about patients experiencing hypokalemia. When the normal K+ concentration falls below approximately 1/2 to 1/3 the normal value (4.5 mEq/L) , muscle paralysis or at least severe muscle weakness often develops. This is caused by effects on the nerve and muscle fibers membranes that prevent transmission of the normal action potentials.

[cbtengr]

I have found myself doing a lot of physical work in very hot and humid conditions. I sweat profusely and at night I experience some pretty severe cramping in my legs. I make it a point to stay hydrated in order to avoid the cramping but am still having some issues. How important are the intake of electrolytes in order to control the cramping?

Rather than spend large amounts of money on sports drinks such as Gatorade I make my own, the wife found the recipe online and it consists of the following:
1/4 Cup lite corn syrup
1/2 teaspoon of Lite Salt Iodized Salt and Potassium Chloride
Sugar free flavoring
2 qts of H20

Is this recipe adequate? Do any of you have your own concoctions that you would recommend?

[CSB]

When we were in Somalia (101st Airborne, 1984) our medics would insist that from time to time we piss on/on a device that looked like a flute. Then they would look through an eyepiece and declare what the specific gravity was. Then they would say "Your'e OK, or drink more" and so on.

I had never seen this before, and havent seen it since. Portable urine specific gravity testing as a way to avoid dehydration.

Is this a valid procedure?

====

Oh, by the way, the best training drink ever: I invented this myself when training at Ft. Bragg in the late 1970's:

Gatorade and cheap white wine, half and half, ice cold.

Yummers, extremely refreshing, and I never suffered from dehydration even when rucking/running in a North Carolina summer.