heat stress relief.


Weapons free
Feb 8, 2008
Well all this talk of heart attacks got me thinking that It would probably be nice to get some nurse/doc/med opinions on the best way to cool off or signs to watch out for during summer training..

Like two or three years ago I went to Summer Leadership School.. and during the more physical out door activities one of the ways we started cooling off was to pour cool water over the interior side of our forearms.. I donno how good of and idea it was as far as physically, but it definitely cooled me off..
Well if we are going to talk about heat illnesses lets talk about them...

There are 3 classes (major ones) of heat illness which one may encounter while working outside in the heat, during physical training or real world operations. I have added a couple of the more minor ones.

I will briefly run down their s/s and treatment of each. Remember the best treatment is prevention. Proper hydration and acclimatization to the environment you are working/training/operating in is the key to avoiding the illnesses listed below. The only exception to this is the first illness. That being said:

Prickly Heat:
1) Red rash that develops over actively sweating skin
2) Prickly sensation/pain over same area (caused by dysfunction of the sweat glands when blocked by salt crystals)

1) Cool and dry affected area
2) DO NOT apply creams to the area
3) Wash area with soap and a loufa(sp?)
4) If itching is severe, 25mg Benedryl PO q 4-6 hours for itching

Heat Syncopy:

1) Cool victim and give cool fluids (powerade/gatorade, cut 50/50 with water) once he/she is alert and awake. The colder the fluid the better as its more easily absorbed by the stomach, however warm fluids are better than no fluids.

Heat Cramps:
1) Painful muscle cramps which generally occur in the more heavily worked/exercised muscle groups
2) Onset during or immediately after work/training

1) Move to a shaded/cool area
2) Rest
3) Drink cool fluids (powerade/gatorade, cut 50/50 with water)

Heat Exhaustion:
1) Malaise, headache, weakness, nausea, vomiting (flu-like symptoms)
2) Tachycardia (rapid pulse > 100 bpm)
3) Sweating (usually profusely)
4) Temp usually normal (100.4 to 102.2 range)
5) Normal mental status

1) Move to shaded/cool area
2) Remove tight clothing
3) Drink cool fluids (powerade/gatorade, cut 50/50 with water)
4) Place ice/cold packs on the neck, groin, chest wall, under arms, in groin (dont place ice directly on skin)

Heatstroke: This is a true medical emergency and should be treated as such. The death rate is 80% when not treated effectively and properly.
1) High temp (usually over 105)
2) Confused, disoriented, seizures, unconsciousness
3) Rapid breathing
4) Rapid pulse (over 100 BPM) and often very weak
5) Sweating may be present or absent

1) Call 911 if you are in an area where they can reach you. (Obviously this precludes operational environments as well as many training environments, however if training you should have an emergency plan ICO an accident.)
2) RAPID cooling (the faster the better). Place ice/cold packs on the neck, groin, chest wall, under arms, in groin (dont place ice directly on skin) or immerse in cool water if possible only until body temp has fallen to 102.2
3) Maintain the airway / NOTHING by mouth
4) Administer IV fluids (1-2 liters NS)
5) Treat for shock

Hyponatremia: Caused by drinking large volumes of h2o or other hypo-osmotic fluids. Often times it can be difficult to differentiate hyponatremia from heat exhaustion/stroke in a field setting because of the over lap of s/s. The most major difference is hyponatremia patients generally have a normal temp (less than 101) and heat exhaustion patients are generally greater than 102. This is a true medical emergency as well.
1) Weakness
2) Lack of appetite
3) Nausea/Vomiting
4) Muscle Cramps
5) Lethargy, apathy, confusion, agitation, seizures, disorientation, unconsciousness

1) Call 911 if you are in an area where they can reach you. (Obviously this precludes operational environments as well as many training environments, however if training you should have an emergency plan ICO an accident.)


Thanks for the great breakdown of heat related illness, SC.

A couple of small hydration tricks to remember when you are exercising in the heat:
First, make sure that you weigh yourself before and after your training session. As a general guideline drink two cups of water for every pound that you lose during your work out.

Second, Gatorade has a fair amount of carbs in it, which I understand actually prevents the absorption of electrolytes into your system. For a number of years NFL players have been drinking infant Pedialyte during training camp to improve electrolyte absorption. The Pedialyte doesn't have any carbs in it, so it doesn't taste as good as Gatorade. However it comes in flavors so it isn't terrible to drink.

Finally, remember that when the Temperature Humidity Index becomes 103 degree f. or more, you have to slow down no matter how fit you are or how accustomed to the heat you are...
Thanks for the good imput Crip and Typhoon.. awesome information..

But I was wondering why Crip was cutting the Gatorade/Powerade 50/50 with water.. is that because the above mentined, carbs preventing the electrolites being absorbed?

Or are their other reasons against Gatorade/Powerade?

I quit drinking the them in turn for just water during and whey protein + milk after my workout, because I was told that unless I was training for a marathon or something that I wouldn't lose anything that water couldn't replace while I was working out..
that I wouldn't lose anything that water couldn't replace while I was working out..
Gatorade does serve a purpose, however. When it is extremely hot you can also drink too much water and end up causing yourself problems because you are diluting your system and not replacing electrolytes. An extreme example would be the woman who literally drank herself to death by consuming too much water a couple of years ago in order to win a radio station contest...
Awesome posts Crip/Typhoon,

Straight gatorade has too many carbs that is correct. It can actually dehydrate you, as it is hyperosmotic and will pull fluids into your GI tract. In some cases this can actually cause diarrhea (or worsen it if you have a GI bug). Drinking a concentrated protein solution will actually do the same.

This is the reason behind the 50/50 mix. A 50/50 mix should nearly match a physiologic electrolyte solution such as pedialyte which is deigned to be iso-osmotic and readily absorbable from the GI tract. Plus it is more palatable than pedialyte (I always wonder why these products designed to be taken by kids taste so awful... but I digress).

Some other tips... really cold fluids on a warm day or if you are overheated can stimulate the vagus nerve, which is a big nerve that runs along your esophogus through your chest. The vagus nerve controls your parasympathetic nervous system, which will slow your HR and lower your BP. Hence, ice cold fluids = vaso-vagal episode = possible syncope. Cool fluids are best. Warm fluids will hydrate you fine, just probably not taste as good on a warm day! The temperature of the fluid before it hits your stomach will not have an effect on the absorption.

Remember... oral hydration is the same physiologically as IV hydration... so the only reason to give IV fluids is if the person cannot tolerate oral fluids (i.e. vomiting or altered mental status).

Crip's point about hyponatremia is well heeded. Sweat contains electrolytes such as sodium... so if a person hydrates with just straight water, his or her blood sodium level will fall. This causes swelling of the brain. The blood brain barrier prevents the movement of salt out, so the blood will have more water than salt, and therefore water will shift into the brain, causing edema. The problem is... as a responder you will be faced with a warm confused patient, and it is easy to presume heat stroke as the cause and rapidly infuse fluids. Rapid correction of hyponatremia can make the condition worse. It is very important if you are in charge of the health of your team to ensure rehydration with physiologic electrolyte solutions to prevent this from occurring, because treatement and ID in the field is exceedingly difficult.

And as for the major's original post... any method of keeping yourself cool and hydrated is okay, within the guidelines we have discussed here... so your method was fine.

EMSDoc :cool:
Hyponatremia and hypokalemia and hyper or hypo calcemia are all very closely tied together as these are the 3 major electrolytes in the human body - plus the sodium/potassium pump in the nephrons not only needs those 2 eltrolytes, but calcium and water to work properly. the body is a balancing act - and under stress the balance can be very skewed.

Too much or too little of any one can throw off the absorbtion or excretion of either or both of the others - or even water...
What about putting a small amount of salt (like a pinch) in a gallon of water.. would that work to maintain proper sodium levels..

I also heard something about throwing in a banana too, something about the potassium helping with the diffusion of salt through the cells or something.. I'm not talking about cramps persay as heat cramps aren't necesserely caused by a potassium deficiency, but it can cause other problems.. Hypokalemia? could that be an issue just from the heat, or would there have to be underlying factors to provoke something like that..
I had a guy going down due to heat one exercise, no medics around as we were too far forward for pussy medics to be there }:-)

I made the affected guy drink a full canteen with one MRE packet of salt and one of sugar mixed in within one hour, it turned him around nicely, no problem after that.
Hypokalemia: Potassium losses (hypokalemia) become apparent after the acidosis is corrected. If severe, it can cause weakness, muscle cramps, and heart rhythm disturbances (such as premature beats). Your body will move potassium out of the cells to partially correct the loss. It may take hours to correct. You'll get potassium from yogurt, bananas, and (a tiny bit) from sport drinks. If you're taking some types of blood pressure medicines or diuretics (water pills) potassium loss can be a problem.


True that diarrhea and vomiting CAN be causes, I was just inquiring to the possibility that it can be onset by Heat Stress..
we will give you initial guidance and point you in the right direction - you have to do your own research and legwork - sorry.

New assignment - find five possible long term effects of a moderate to severe heat injury and figure out if any of them can become life long disabilities.
Low potassium can be a pre-exisiting condition due to diet, or can be induced by vomiting/diarrhea. Potassium can be lost in sweat, and there are many electrolyte shifts that occur when homeostasis in the body becomes affected by any stress (heat being one of them).

As for "homemade" electrolyte replacement solutions... ideally commercial ones are best because they are specifically designed for that purpose, however MacGuyer-ing a solution at times is all that is practical. The best answer is if you can prepare and bring gatorade or pedialyte beforehand, 50/50 gatorade or pedialyte are preferred. But if you are in the trenches or it is not practical to carry cases of gatorade with you... then you have to do the best with what you have. Another option... there are commercially available dry packets available that don't take up much space that you can add to any source of water to make an electrolyte solution.

Doc :cool:
Prevention is always best.

I always made sure to get people into shade and check on them on hot days.
Does anyone have stats as to how many people have been lost to Hyponatremia and to heat stroke etc...

I'd like to see a comparison between the two.

I'm still more than a little uneasy with the whole 'drink lots of water' mentality of the Military nowadays, goes against all my training.
The body can be trained to operate on small amounts of water, which is IMO vital to certain types of troops.
Dinosaur...:p Tell us about the leaches/bleedings and brandings you got at the RAP and what drill is like with a SMLE.

Leeches have valuable applications and the SMLE is the best bolt action military rifle ever made, I have three with me now (including a Lithgow).

So fuck you! :p :D

You are all water drinking pansies, In the words of Chopper, Harden the fuck up!
Lets say you have a heat injury such as exhaustion, but you are drinking plenty of water. You vomit, but its mostly clear water as your stomach is full. How can you get the body to absorb the water faster to prevent the injury?

or are you just S.O.L.?

Also while im at it, How long would you say it takes the average person to climatize to an area? If your only there 1-2 weeks, can you acclimitaze? If not again, are you just S.O.L.?