Wednesday, August 10, 2011

Don't Fry Your Body in Pre-Season

Heat-related illness is the most common cause of illness and even death in athletes at this time of year.  Korey Stringer was a Minnesota Vikings player who died in August of 2001 from exertional heat stroke.   The Korey Stringer Institute at University of Connecticut is dedicated to the prevention of sudden death in athletes and is supported by Korey Stringer's widow. 

There are two basic physiologic processes that contribute to this problem. These are dehydration and hyperthermia:

Dehydration is the process of water loss leading to hypohydration. Usually measured by body mass loss, urine color, urine osmolality, urine specific gravity or via serum osmolality (gold standard).

Hyperthermia is a body temperature elevated above 39°C or 102°F.

And here, from the Korey Stringer website are some other definitions, in descending order of severity:

Exertional Heat Stroke (EHS)- a medical emergency involving life-threatening hyperthermia (rectal temperature > 40°C, 104°F) with concomitant central nervous system dysfunction; treatment involves cooling the body.

Heat Exhaustion- Inability to continue exercise in a hot environment due to cardiovascular insufficiency usually in combination with prolonged heat exposure, cutaneous vasodilation, muscular exertion, and dehydration.

Heat Syncope- A brief fainting episode in the absence of salt, water depletion, fluid loss or
hyperthermia, often subsequent to prolonged standing.

Heat Cramps- Painful spasms of skeletal muscles, usually after exercise in a hot environment.

For some really frightening stories about illness and two recent deaths on the football field check out this blog, Training and Conditioning

Here are some basic guidelines laid out for athletes by the Korey Stringer Institute:

1. Listen to your body- if you do not feel well, back off (lower your intensity) and seek help if you continue to feel lousy.

2. Hydrate yourself- try to keep your urine color like lemonade and not like apple juice.

3. Listen to your thirst- if you are thirsty, you need fluids.

4. Phase in exercise in the heat- called heat acclimatization, the first 7-10 days should gradually include an incremental increase in intensity, duration, equipment, etc.

5. If your teammate, child, athlete, friend, colleague, look like they are struggling in the heat, seek shade/ice/fluid/rest for the person. If they do not start to do better immediately, call 911.

6. Be sure that an athletic trainer is employed by your high school to take care of the prevention, recognition, and treatment of emergency situations in sport.

7. Be sure to educate coaches and athletes about these tips and the common signs and symptoms of heat illnesses.

8. Realize that your performance will be about 10-15% worse in the heat as compared to cooler climates. Adjust pace, intensity, and effort accordingly.

9. Be sure you are getting enough salt in your diet/sports drinks/sport foods. Sodium assists with the hydration process and you lose a lot in your sweat during intense exercise in the heat.

10. If someone is suffering exertional heat stroke, cool them immediately using cold water immersion, the amount of time hyperthermic (not the temperature obtained) is the key to outcome being life or death.

Most school athletic departments have guidelines that encourage coaches and trainers to pay attention to the Heat index and the Real Feel Temperatures when they are practicing.  Of course, they need to remember that the index at noon is very different from what they will feel later inthe afternoon.   Schools should have policies that call for cancelling practice when the Heat Index is over 95 degrees Farhenheit. Here is a website for New York State that charts the correct actions to take based on the Heat Index.  And here is a fairly good explanation of the difference betweeen Heat Index (essentially a mix of heat and humidity) and the (Accuweather) Real Feel Index (more complex that takes cloud cover, wind and other factors into account).

Knowing that the country is in the grips of a severe weather system, there is no reason to believe that the temperatures and humidity will vastly improve before pre-season starts.  It's a good idea to start acclimatizing by spending time in the heat and humidity and beginning to work out under the hot conditions to get the body accommodated.   Although water is generally good enough to hydrate most athletes, when there is a great deal of sweating, electrolyte containing drinks are going to be much better.

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