Why Sweat the Heat?

An alien on Star Trek referred to the Enterprise crew as "ugly bags of mostly water."  According to Lt Commander Data "that would be an accurate description, since 90% of the human body is comprised of water."  If we have that much water, why does it matter if we lose a little in sweat? 

Did you ever see what happens to grapes when they are left in the sun?  Although it's popular in California to be a raisin, I don't recommend it here.

The body can tolerate small fluid losses, but large losses that occur with hard work and exercise in hot weather cause problems.  Your car would have problems too if you attempted a cross-country journey in the summer without plenty of coolant.

When body fluids are lost they have to come from somewhere. The first place that fluids are lost from is the blood.  If the fluid loss is significant,  the blood pressure falls reducing oxygen flow to various parts of the body � much like turning down the water to a sprinkler reduces water to the distant corners of the yard.

If you understand this idea, you can better understand all the symptoms of heat stress and dehydration:

The first place that the body starts to have problems is in the muscles.  During exercise and strenuous work, the muscles give off 30 times more heat than at rest.  When it is hot outside, this heat builds up.  Reduced blood flow from dehydration results in less oxygen delivered to the muscles, and a build up of waste products which cause fatigue, cramping and spasms in the legs, arms and stomach.  These HEAT CRAMPS  are the first warning signs of heat stress and dehydration.  To treat� stop what you are doing, get out of the heat, drink lots of fluids and apply ice packs to groin and armpits.

This next phase of heat stress is more serious, it is called HEAT EXHAUSTION.  Reduced blood flow to the brain, may cause lightheadedness, headache, pronounced weakness, visual disturbances and drowsiness.  The heart will try to help out by pumping the remaining blood around faster � so the person might feel his or her heart racing too.  The person's skin may be cold and clammy and the body temperature may rise as high as 104�.  This is a serious condition and the person must get to a cool place immediately, drink plenty of cold fluids, soak and loosen clothing, and call your doctor.

The most critical phase of heat stress is HEATSTROKE.  Symptoms may include loss of coordination, disorientation, vomiting, diarrhea, warm dry skin with NO sweating, weak rapid pulse,  and eventually unconsciousness.  Body temperatures may soar as high as 106�.  Treat as before and call the ambulance. IF NOT TREATED IMMEDIATELY THIS PERSON MAY DIE!  Their body has lost all ability to regulate temperature and unless cool intravenous fluid is given rapidly and aggressively the person may experience heart failure. 

RULES OF HEAT ENGAGEMENT

• Drink lots of fluids. (1 - 5 gallons per day)  Use your urine color as a guide, if it isn't clear and colorless, you aren't drinking enough.
• Avoid sugary, caffeinated drinks and alcohol.  These act as diuretics and pull needed fluids from your body.
• Acclimate yourself gradually to the heat.  Slow down your workouts and pace your activity to allow yourself a chance to get used to the heat.
• Exercise and do your most strenuous work in the cool parts of the day (before 10 AM and after 5 PM)
• Watch your fellow campers and your new scouts carefully � they may not know the signs of heat stress and may continue to push themselves past the warning signs.

Emphasize aggressive water intake.  People must start drinking before they get thirsty. Drink water before, during and after heat exposure and plan frequent breaks during the heat of the day. Staff, Scoutmasters, SPL's, and Patrol Leaders THIS IS YOUR RESPONSIBILITY.  HEAT STRESS is a preventable illness.  It is one of our largest summertime threats to personal safety.

by David W. Fairbanks, M.D.
Medical Director, Goshen Scout Reservation