Difference Between Hyponatremia and Dehydration

With summer creeping up on us and our desire to get outside more comes a need to drink more water.  However, understanding how much water to drink and when is crucial, especially when it comes to running, hiking or biking long distances.  We naturally assume we must consume more water because we sweat, but we also must need to make sure we don’t over hydrate.  Hyponatremia (hypo= Low; nat = Sodium; emia = blood) low blood sodium,is a condition where the normal amount of sodium is diluted to a point where normal body function is altered.  On a sad not hyponatremia has been know to kill many hikers, marathon runners and military personnel every year.  This is why I wanted to put out there how to recognize the difference, what to do about it and how to prevent it.

What is the difference between Dehydration and Hyponatremia?

(signs and symptoms)

Hyponatremia Dehydration
Headache Lightheadedness
Confusion Confusion
Seizures Heart palpitations
Muscle cramps Muscle cramps
Weakness Weakness
Vomiting Vomiting
Weakness Weakness
Lack of sweating

As you can see the symptoms of both of these are VERY similar.  Treating either one incorrectly can and will lead to death.  SO what do you do in the case you feel someone is suffering from either one of these?  DO the opposite!  If they are dehydrated get them fluids.  If they are hyponatremic STOP giving them fluids or give them stuff with salt in it like a pretzel, sunflower seeds or Gatorade (be careful with this one as they already have to much fluids).

So how do you tell which condition you are dealing with?

The easiest way to prevent both of these is to weigh yourself before and after exercise.  It is becoming more of a standard for people to weigh themselves prior to marathon event.  The idea being that if you sweat too much you will lose weight and if you drink to much you will gain weight.  The goal is to weigh the same before and after.  This suggests that you hydrated appropriately for the activity.

I read a study a while ago that said almost 80% of the people who run marathons become hyponatremic at some level! Why? In order to prevent dehydration they end up drinking at every drink station.

The rule to live by is 1 lb = 16 oz of water or Gatorade.  If you weight 180lbs before your run and 182 after your run you need to back down on the amount of water you are drinking.  Like wise if you weigh 150 (before) and 148(after) you should drink about 32 ounces of water/Gatorade immediately upon completion of your run.

Getting the weight of you and a friend prior to every run may not always be a viable option and unfortunately you see you friend showing some of the signs and symptoms mention earlier, so how do you determine what the next best option to help you friend recover is? Ask them!  Find out when the last time they drank some water or how often they were drinking.  This will be important information you will be telling the medical personal you called to help you with this situation.  Remember this is a serious situation and in either case you need to call 911 and get advanced medical personnel to the scene.

It was my goal to bring some light onto these conditions and show how similarly they can present themselves.  Take care of your neighbors as you rock your 5Ks,13.1s, 26.2s and century rides this summer!



I would love to know if anyone has ever suffered from either of these:


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