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Sweltering in Oklahoma

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Sweltering in Oklahoma!





Ready for Oklahoma's "100-degree season"?

Summer heat waves can last days or weeks, and when they do, they have the potential to cause many deaths from hyperthermia ("hot body"). The University of Oklahoma and its Police Department are very concerned about the safety and well-being of the university community and wish everyone to stay safe and healthy during hot weather.

Most healthy adults can cope with heat; their bodies are able to maintain normal temperature
—up to a point. The body maintains its temperature primarily through sweating. When body heat rises above the norm, the brain causes the blood vessels in the skin to dilate, providing increased blood flow at the surface of the body and supplying increased fluids to make sweat. As perspiration evaporates, it cools the surface of the body and lowers body temperature.

When the weather is humid as well as hot, sweat doesn't evaporate as quickly, slowing the cooling process. Humidity above 75% can stop evaporation, allowing body temperature to rise. Thus, the body is better able to tolerate heat when the humidity is low.

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At-Risk from High Heat

Although anyone, at any time, can suffer from heat-related illness, some people are at greater risk than others. Check regularly on:


  • Infants and young children up to 4 years of age
  • Persons over 65, and particularly those who have health problems involving their heart, kidneys, or lungs
  • Persons who are overweight
  • Persons taking diuretics, sedatives, tranquilizers, antihistamines or any other medication which interferes with their ability to perspire
  • Persons who overwork or exercise excessively in the heat
  • Persons who are dehydrated or have poor circulation, reducing the ability of their body to deliver blood to the skin
  • Persons who have a mental illness
  • Persons who are physically ill, especially with heart disease or high blood pressure


Visit adults at risk at least twice a day and closely watch them for signs of heat exhaustion or heat stroke. Infants and young children, of course, need much more frequent watching.


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Beat the Heat!

3 Stages of Overheating

Prolonged exposure to excessive heat causes symptoms that become progressively worse unless you get out of the heat and do what is necessary to care for yourself.


1.     Initially, exertion in heat and/or lack of water (or loss of water and salt from heavy sweating) will cause cramps; painful spasms that usually center in the legs, but can also occur in the abdomen and arms. (A note regarding "thirst" — By the time your body tells you that you are thirsty, you're already mildly dehydrated.)

Also, persons poorly hydrated, or poorly acclimatized to heat, or standing for long periods (or who stop/stand abruptly after working/exercising) in the heat, may feel suddenly weak and dizzy, or may actually faint!

Should you get cramps, or suddenly feel weak/dizzy, stop what you are doing, rest in a cool area, and drink clear juice or a sports beverage. With shade and rest, faintess or dizziness should subside promptly. If cramps persist for more than an hour, see a doctor.


2.     Heat exhaustion comes next. Your body temperature is still normal, but your skin is cold and clammy, you're thirsty, become uncoordinated and feel dizzy. You may feel faint, and your heartbeat may be rapid. You must immediately be rehydrated with water, salt and minerals. If these symptoms persist even after you're cooled down, see a doctor. ONLY let persons exhibiting these symptoms have water or sports drink IF THEY ARE FULLY CONSCIOUS and can protect their own airway, as nausea and vomiting are also signs of heat-related illness.


3.     Finally, there is heat stroke. If you've let things get to this stage, you're in serious trouble. As your condition deteriorates, your body actually stops sweating — so beware of dry, hot red skin. Your body temperature is above 103 degrees F, your skin is dry and flushed (red), your pulse is strong and rapid, your mental state is impaired, —you're on your way to a coma. You may die unless you're treated immediately.

If you see someone with these symptoms, call for an ambulance. While awaiting its arrival, get the victim out of the heat. Loosen or remove clothing, wrap the person in wet towels or clothing, and apply ice packs around the neck, the groin and under the arms and knees (where the blood flow is greatest and closest to the surface). Do NOT allow oral hydration if mental impairment is observed (and it is usually present in this condition).

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The best defense is PREVENTION.

Here are some precautions you can take 


  • Wear lightweight, light-colored loose-fitting clothing.


  • Apply sunscreen with a Sun Protection Factor (SPF) rating of at least "SPF 15" to exposed portions of the body


  • Limit exposure during the hottest hours: 10 a.m. to 4 p.m.


  • If possible, avoid strenuous work or exercise outside.


  • Take advantage of shade in the environment and/or wear a wide-brimmed hat.


  • Stay in air-conditioned areas or use cooling fans to speed sweat evaporation.

    Stay indoors and, if at all possible, stay in an air-conditioned place. If your home does not have air conditioning, go to the shopping mall or public library-even a few hours spent in air conditioning can help your body stay cooler when you go back into the heat. Call your local health department to see if there are any heat-relief shelters in your area.

    Electric fans may provide comfort, but when the temperature is in the
    high 90s or above, fans will not prevent heat-related illness. Taking a cool shower or bath, or moving to an air-conditioned place is a much better way to cool off.


  • Drink lots of cool, non-alcoholic fluids. If you're exercising or working, drink 2 to 4 glasses of water an hour. If you lose a lot of fluid on a hot day, sports drinks are preferred over water because they will replenish sodium.

    Check with your doctor if you have health problems that require you to limit fluid intake or you're taking diuretics — ask him/her how much you should drink while the weather is hot.
Beat the Heat!


  • Don't wait until you're thirsty to drink.
    Drink more fluids (nonalcoholic)
    regardless of your activity level.

Don't rely upon
thirst as an indicator of your need for water; it's not reliable in very high heat.


  • Don't drink liquids that contain caffeine, alcohol, or large amounts of sugar —these actually cause you to lose more body fluid. Also, avoid very cold drinks, because they can cause stomach cramps.


  • Avoid hot foods, and keep meals light — Put less fuel on your inner fires. Foods (like proteins) that increase metabolic heat production also increase water loss (the body has to work harder - and use more blood - to digest heavy foods).


  • NEVER leave anyone in a closed, parked vehicle. Certainly don't leave children or pets in a vehicle, even for "a few minutes." Heat builds up rapidly to exceptionally high temperatures in a closed vehicle, and it doesn't take much exposure to make children or pets very ill.

Pay attention to warning signs:


  • Red, hot sweaty skin, cramps, lightheadedness and fatigue will occur long before heatstroke.


  • Remember the old Scouting saying, “If your pee is clear, you’re in the clear.” Colorless and very light yellow urine is a sign of a good, healthy level of hydration. Difficulty urinating and dark yellow or amber urine may be a sign of dehydration.


  • If you find it difficult to spit, or have thick, foamy saliva, you may be in danger of serious dehydration.


  • Get out of the heat immediately and seek medical attention before serious harm is done.


Heat Index / Heat Disorders Chart and Relative Humidity vs. Air Temperature Chart

For more information on the Heat Index, view the "Heat Wave" online brochure produced as a cooperative effort of NOAA’s National Weather Service, the Federal Emergency Management Agency, and the American Red Cross.

Also, you can view NOAA's HEAT: A Major Killer presentation HERE. And, you can click HERE to view an excellent presentation on The Heat Index from the NWS Forecast Office in Norman, OK.

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If you must be out in the heat:

Be resourceful and creative –


  • Try to limit your outdoor activity to morning and evening hours.


  • Cut down on exercise. If you must exercise, drink two to four glasses of cool, nonalcoholic fluids each hour. A sports beverage can replace the salt and minerals you lose in sweat. Warning: If you are on a low-salt diet, talk with your doctor before drinking a sports beverage. And remember – don't wait until you're thirsty to drink.


  • Slow down. Try to rest often, in shady areas.


  • Protect yourself from the sun's UV radiation by wearing a wide-brimmed hat (also keeps you cooler) and sunglasses and by putting on sunscreen of "SPF 15" or higher (the most effective products say "broad spectrum" or "UVA/UVB protection" on their labels). Wear lightweight, light-colored loose-fitting clothing.


Sunburn Prevention Tips:

  • Apply a broad-spectrum sunscreen with a SPF rating of at least "SPF 15". Reapply sunscreen every two hours, outdoors, even on cloudy days. Sunscreen is particularly important for children under 6 years of age.


  • Cover thyself! Consider wearing sunglasses, a wide-brimmed hat, and lightweight (but protective), light-colored, tightly-woven clothing (that prevents direct exposure of skin to sunlight) such as a vented long-sleeved shirt and full-length pants (rather than t-shirt and shorts).
No shadow? Seek the shade!

When buying clothes for outdoor activities, look for clothing with SPF ratings of at least "SPF 15". Modern outdoor clothing rated at "SPF 30" and "SPF 40" is commonly available. In contrast, an ordinary cotton t-shirt offers an SPF rating of only "SPF 5" to "SPF 9" (and, when damp, much less than that) —well below the minimum "SPF 15" recommended by doctors for even minimal exposure.


  • Avoid reflective surfaces (including water) which can reflect up to 85% of the sun's damaging rays.


  • Don't have a shadow? Seek the shade! If your shadow is shorter than you are, you're likely to sunburn. Stay in the shade whenever possible.


Sun Protection Recommendations: UV Index and Key

This chart, above, is the KEY for the UV Index Map. Click HERE  or on the "example" map (right) to visit Today's UV Index map.

(For more information, see the EPA's "A Guide to the UV Index".)


The current UV forecast map  (click on the example map, right) shows predicted UV exposure levels for "solar noon" —the time during the day when the sun appears to have reached its highest point in the sky. Usually, this is not the same time as "clock noon". The relationship between clock noon and solar noon depends on your location within your time zone and the time of year.




The UV Index Forecast Map and Bulletin (linked above) are generated around 1:30pm EST daily. If the originating information is considerably delayed, these products may NOT be updated. An alternative site for the UV Index Bulletin (a "text" product) which is operationally updated:


Today's "UV Index" Contour Map


To view a large "4-day" contoured analysis of Today's UV Index over the U.S., click on the “example” map, right, to go the EPA's SunWise program website. (

For more information on the "UV Index",

click on these "question" links, below 


(The questions, above, link to the NOAA/NWS Climate Prediction Center's UV Index Information page.)

You can also look up today's UV Index for your location from U.S. EPA's "SunWise Program" website.

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"Working" in the sun?

Or do you supervise others working in the sun?


1.     Educate yourself and your workers about the risks of heat and sun exposure. Include treatment of heat-related problems in first aid training.


2.     Use common sense when determining assignment for work in hot environments. Lack of acclimatization, age, obesity, poor conditioning, pregnancy, inadequate rest, previous heat injuries, certain medical conditions and medications are some factors that increase susceptibility to heat stress. Employees with medical conditions or taking medications should ask their doctors before working in hot environments.


3.     Make water available, and encourage regular hydration.

Discourage intake of alcohol, coffee, tea and caffeinated soft drinks, which cause dehydration.


4.     To the extent practical, ensure good ventilation in all work areas. Provide spot cooling in work areas of high heat production.


5.     Assign a lighter workload and longer rest periods during periods of intense heat. Short, frequent work-rest cycles are best. Alternate work and rest periods with longer rest periods in a cooler area, and schedule heavy work for cooler parts of the day.

Promote hydration during all rest periods.


6.     Regularly check on workers exposed to high heat. Monitor workplace temperature and humidity and check workers' responses to heat at least hourly during periods of intense heat. Be alert to early signs of heat-related illness and allow workers to stop their work for a rest break if they become extremely uncomfortable.


7.     Be familiar with the indicators of heat-related health problems. All workers should learn to spot the signs of heat stroke, which can be fatal.

Get emergency medical attention immediately if someone has one or more of the following symptoms: mental confusion or loss of consciousness, flushed face, hot, dry skin or has stopped sweating.


For more information relating to heat/health issues for employers/employees, view/print OSHA Quick Card: Protecting Workers from Heat Stress (

Also, for cold weather health issues, view/print the OSHA Cold Stress card, which provides a handy chart for exposure risk at LOW temps. Also, visit the NWS "Wind Chill Chart" webpage.


For more hot weather health information...

Visit the CDC's "extreme heat prevention" guide –



and also,




This “Sweltering in Oklahoma!” publication was created by Neal Stone and Richard Hamilton (EMT-A members of  OUPD’s former “Project M.E.D.I.C”)   with assistance from “friend of OUPD” Keith G. Plummer, PA, Director of Emergency Medicine at Johnston Memorial Hospital in Tishomingo, OK.  Created in 2005.  Updated in March 2012.