Heat Related Injuries

Heat Related Injuries

Michael W. Dickey, MD

Medical Director: Hill Country Urgent Care

 

It is summertime again.  100-degree temperatures are an every day occurrence. For those of us that work or play outdoors in Central Texas it is an important time to listen to our bodies.  Whether we are an athlete, stonemason, or a homeowner working around the house, lost efficiency and productivity as a result of the Texas heat is an annual rite of passage.  Failure to take into account the effects of heat on your body can be disastrous.  Some simple precautions can make all of us more resistant to the effects of the summer heat. 

The range of symptoms that can result from heat exposure are varied and may go unrecognized.  The common heat injuries are heat edema (or swelling), heat syncope (or fainting), heat cramps and the more severe problem of heat exhaustion.  The less common injury is heat stroke.  A heat stroke is a life-threatening emergency that needs immediate medical attention.

Heat edema is swelling that particularly occurs in the legs, feet and hands.  It is the most common and mildest heat injury.  It typically improves with elevating the affected parts of our bodies.  We become more resistant to heat edema with acclimatization to the summer heat.

Heat cramps are painful spasms of muscles that often affect the hands, arms, legs or our abdomen.  Heat cramps can be a warning sign of an impending more severe problem, heat exhaustion.  Heat cramps result from excessive loss of fluid and salt and typically respond to replacement of lost fluids and salt.  Salt can be replaced by consumption of salty foods such as chips or pretzels.  Alternatively, adding one teaspoon of table salt per quart of water makes an appropriate replacement fluid.

Heat syncope is fainting or dizziness that occurs after prolonged standing or sudden rising from a sitting or laying position.  It resolves immediately with laying the affected person in flat position and replacing fluids.  Usually the affected person can consume fluids while lying in a supine position until able to stand upright again.

Heat exhaustion results in a group of more severe symptoms that include:  severe sweating, generalized weakness, headache, dizziness, nausea, vomiting, chills, blurred or altered vision and skin flushing.  Also with heat exhaustion, the affected person's body temperature can rise dangerously close to the level needed to cause a heat stroke.  A person affected by symptoms of heat exhaustion should be moved to a cool area to rest for several hours.  They will need to consume 3-4 quarts of replacement fluid over a 3-4 hour rest period.  If the victim is unable to take fluids because of vomiting, or if recovery does not occur over this period, medical intervention is needed.

Heat stroke is a rare but life threatening problem.  Body temperatures of 105F or higher and mental confusion are the main characteristics of heat stroke.   The misconception that all victims of heat stroke cease to sweat is not accurate.  Heat stroke as a result of exertion, such as in an athlete or worker is often associated with continued sweating.  The "classic heat stroke" is an event that generally occurs in the elderly or very young.  It is not necessarily associated with exertion, but is simply a result of prolonged heat exposure.  It is "classic heat stroke" that results in a “hot and dry person” who has ceased to sweat.  Either type of heat stroke is a true medical emergency.  911 (Emergency Medical Services) should be notified immediately in any situation where a heat injury is associated with confusion or elevated body temperature.

Yes, we can do several things to help prevent heat injuries.  The simplest and maybe the most important thing we can do is to allow our bodies to acclimatize, the process of becoming accustomed to exercising in the heat.  Essentially, the body becomes more efficient with repeated exercise in the heat; the body produces less heat of its own and dissipates the heat more effectively.  Adults require 4-7 exercise sessions in the heat of 1-4 hours duration to facilitate the acclimatization process.  Children require somewhat more.

Adequate hydration decreases the susceptibility to heat injuries.  The amount of fluid needed to maintain hydration is usually underestimated.  The thirst reflex should not be our only guide to our fluid intake.  Hydration before exertion in the heat should consist of 16 oz of fluids and an additional 8 oz of fluids every 20 minutes. 

In outdoor activities such as tennis it is recommended to take periodic breaks in the shade while cooling down with cold water or ice prior to returning to the tennis court.  Certain brands of bottled beverages such as Gatoraid, Poweraid or Smart Water offer supplemental electrolytes (essential elements for normal body functions) which may help to prevent onset of symptoms associated with heat-related injuries. Sometimes it is just best to follow what other animals in nature do, be active outdoors only in the morning and late evening and avoid outdoor activities during the heat of the day.  For those in Central Texas during July and August, long afternoon siestas are a great way to avoid the heat of midday.

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