Hyponatremia is a condition of low sodium levels within the blood and is typically seen during or after intense physical activity. If not corrected, hyponatremia can eventually lead to brain swelling, seizures, fluid in the lungs, and death.
The cause of hyponatremia in is two-fold; over hydration and decreased urination. Drinking more than 1500 mL of water per hour will dangerously dilute sodium levels within the blood. Decreased urination does not allow the body to rid excess water, further diluting sodium levels. One would think that drinking so much water would naturally lead to more pee breaks.. But for reasons still not fully known, a hormone named ADH is released during intense activity. This hormone is responsible for decreasing urine output, despite massive water ingestion.
A common misconception is the idea that taking salt supplements will negate the develop of hyponatremia. Sodium supplements during exercise lasting less than 18 hours does not prevent hyponatremia. Sodium supplements do not directly increase blood sodium levels. Instead, think of hyponatremia as a water problem, not a salt problem.
"Instead, think of hyponatremia as a water problem, not a salt problem. "
To make things even more difficult, the signs and symptoms of hyponatremia greatly overlap those associated with dehydration and other heat related illnesses. This includes fatigue, increased thirst, decreased urination, nausea, vomiting, dizziness, headache, confusion, blurred vision, breathing difficulty, seizure, and coma. Symptoms of hyponatremia can appear during or within 24 hours after activity.
But how do you treat hyponatremia, especially if it mimics other serious medical problems? The differing key factor is determining how much water the runner has ingested within the 24 hours leading up to the onset of symptoms. This can be done by asking the runner or members of their group.
Restrict further consumption of water. Cases of mild hyponatremia can correct themselves without treatment as long as excessive water intake does not continue. If water consumption continues, the victim will become worse. This restriction also includes standard IV solutions given by medical providers. Be sure to voice your concerns and reasons about possible hyponatremia to medical personnel.
Highly concentrated salt solutions have been shown to increase sodium blood levels and can be an option if you are in a remote wilderness setting without immediate access to care. The Wilderness Medical Society suggests a mix of 3-4 bouillon cubes dissolved in 125ml water. Do not give this solution to someone if they can not swallow. If the person is unresponsive, do not force the salt solution. Place the patient on their side to protect the airway. Seek help. .
The silver lining of good news is that hyponatremia is an ailment that can be easily prevented. Instead of forcing water consumption, drink water only when thirsty. This is the body’s way of communicating its needs. Keep track of how much water you or another person in your group is drinking per day. This will be helpful information when trying to distinguish between dehydration and hyponatremia.
And while salty snacks and foods do not directly prevent low sodium, it's a great excuse to indulge! Bring on the potato chips!
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