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    Hyponatremia and Exercise Associated Collapse

    Tuesday June 10, 2003

    Dr. Addlesburger of Sheridan had some helpful tips for runners and Search and Rescue volunteers at Tuesday's meeting. The meeting focused on the collapsed athlete, also known as Exercise Associated Collapse, or EAC. This usually occurs when a person stops running after a long distance. Ever had that feeling of dizziness or lightheadedness when you stop running? EAC happens frequently at sporting events. While you are running, the blood in your legs is being returned passively to your heart by muscle contraction. When you stop running, it begins to pool in your legs and does not return to your heart to be pumped to your brain and other organs. This is why a lot of athletes collapse after the finish. EAC can be treated easily by just laying flat with your legs and hips elevated. This will return blood to your heart by gravity. Also, when you cross the finish it is wise to continue walking around rather than standing or sitting in one place. If you sit down directly after finishing, the next time you stand up you could find yourself in a frightening predicament! However, the collapse of an athlete can also be caused by more serious conditions such as:

    • Hyperthermia- body temperature is higher than normal (heat stroke).
    • Hypothermia- body temperature is below normal.
    • Dehydration- Excessive loss of body fluid.
    • Hyponatremia- Decreased concentration of sodium in the blood.
    • Hypoglycemia- Deficiency of blood sugar
    Dr. Addlesburger had some helpful advice for runners and medical personnel.

    Hyperthermia and hypothermia are common in races such as this one. In this race you could find yourself in snow at high elevations, or very hot conditions in the canyon. Hypothermia and hyperthermia, in their mild forms are relatively easy to prevent and treat. Wearing the proper clothing and paying close attention to the weather can prevent you from developing hypo/hyperthermia. More severe cases need to be treated by EMS crews or at the hospital.

    Dehydration is not usually a cause of serious problems as one might think. The body can lose up to 10% body weight before serious problems occur. However, if a person gains >2% body weight, serious life-threatening problems can develop. Likewise, Hypoglycemia has a low percentage of serious problems at sporting events. It can usually be treated easily by drinking or eating something sweet.


    Hyponatremia is a condition where the serum sodium (amount of sodium in the blood) is low. The main focus of Dr. Addelsburgers presentation was hyponatremia. In the past, medical personnel were taught to treat more common conditions such as hypo/hyperthermia, dehydration and hypoglycemia. These conditions are common, but research has begun to show that in long distance events, hyponatremia could be to blame for life-threating problems as well. Symptoms include:
    • Headache
    • Incoordination
    • Lightheadedness
    • Dizziness
    • Nausea/Vomiting
    • Bloating
    • Fullness
    • Seizures
    • Coma
    Physical signs of Hyponatremia include:
    • Mental Status Changes
    • Edema (Swelling) in hands and fingers
    • Body Weight gain of >2%
    • White sediment on the skin
    • Decreased or no urine output
    Life-threatening problems developing from Hyponatremia are caused by Cerebral Edema (swelling of the brain), and Pulmonary Edema (fluid in the lungs). Both of these conditions are very serious and could result in seizures, coma and death.

    Hyponatremia can range from mild to severe. It usually occurs while exercising becuase of sweating. The body looses precious amounts of sodium through the skin. When sweat evaporates it leaves the white sediment on the skin mentioned above. Meanwhile, the body tries to compensate by retaining sodium and water from the kidneys. Urine output decreases and in severe cases will stop entirely. While more water is being consumed and no urine is being made, swelling and weight gain occurs. Mild cases can be treated easily by just eating something salty. If it has developed to a serious stage, treatment at the hospital is necessary.

    What can you do?

    Dr. Addlesburger had some helpful advice for runners to prevent hyponatremia:
    • Pay close attention to the temperature. If you are sweating excessively, make sure you are drinking sports drinks (this is better than water, Gatoraid and Poweraid contain a lot of sodium as well as other electrolytes lost through sweat), or eating salty foods. You can also take Sodium tablets. 1gm/hr was recommended (although you need to pay close attention to how much you are sweating, you may not need as much on a cool day as you would on a really hot day).
    • Try not to take Motrin, Aleve, Acetaminophen, or Ibuprofen. Nonsteroidal anti-inflammatory drugs (NSAIDS) are hard on your kidneys. You want your kidneys working at their full potential to prevent hyponatremia.
    • Consume only what fluid your body needs, no more and no less. It was suggested by Dr. Addelsburger to consume less than or equal to 1 Liter of fluid per hour. Those who drink >1-1.5L of fluid per hour put themselves at risk for hyponatremia.
      Helpful tip: While you are training, weigh your self before you leave for your run. Run for 1 hour and then re-weigh yourself. You should consume 16oz of fluid for every 1lb lost in an hour.
    • Pay attention to what your body is telling you. Keep track of how much you are drinking and urinating. If you start to have any of the symptoms above, try eating salty foods and drinking sports drinks to replace the salt you are losing. And please, tell one of the medical personnel that you are starting to feel poorly. They may have some great advice and can help you out of a bad situation before it becomes life-threating. Please realize that all of those medical checks are there for a very good reason.
    • Don't sit or stand around at the finish. Keep walking, you'll need a good cooling off period for long distances.

      What does the medical personnel do?

      Treatment of hyponatremia seems simple, replace the sodium. But it's not that easy. First and foremost the medical crew needs to lay the runner flat with their hips and legs elevated. If EAC is the culprit, this may be all it takes. If the symptoms continue, then they will need to rule out hyper/hypothermia, dehydration, hyponatremia and hypoglycemia. This is done by assessing the following:

      • Rectal Temp (ear and oral temperatures do not reflect core temperature accurately). Hyperthermia is >102F, Hypothermia can range from 86F-98.6F.
      • Systolic Blood Pressure (hyponatremia causes hypotension, or low blood pressure)
      • Pulse (hyponatremia causes tachycardia, or rapid pulse).
      • Hydration status/ Body weight/ Fluid In/ Urine Output (weight loss of up to 10% reflects dehydration, weight gain of >2% could reflect hyponatremia).
      • Previous history of collapse, drug use(NSAIDS, insulin).
      • Previous medical history.
      • Symptoms (listed above)

      When other diagnoses are ruled out and hyponatremia is suspected, the first treatment would seem to be sodium replacement via an intravenous(IV) solution. The first choice of IV solution in an emergency situation is Normal Saline(NS) 0.9% Sodium. In most cases, NS is an appropriate choice. However, in hyponatremia cases the human body will stop making urine in attempt to retain sodium. By the time hyponatremia becomes an issue, all urine output will essentially cease. Giving the patient more fluid will result in fluid overload, or water intoxication. Hyponatremia can only be confirmed in a hospital setting where blood can be tested and watched closely while sodium replacement is being administered. Although intravenous access should be obtained immediately, it is advised that only anti-seizure medications be administered until the patient is receieved at the hospital. Then a solution with a high concentrarion of sodium (3.0% sodium) can be administered. It is very important not to correct the problem too quickly. Sodium replacement is done very slowly to prevent further problems.

      The Bighorn Mountain Wild and Scenic Trail Runs are lucky to have a great Search and Rescue team to watch over our participants. In 11 years we have had a number of people run into problems. Each has had a happy ending. Just remember, they have been doing this for a long time. They take the time to train their members in all conditions that could develop during our races, including hyponatremia.

      Just remember to Run Smart and take Dr. Addelsburger's advice. Let's keep our good record going!

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