Hyponatremia - how I found a solution

You could say it all started a few years ago.

I began having headaches and feeling nauseous the day or a few days after a hard workout. I don't really remember for how long I've suffered from it, but I do know that it's been at least 10 years.

I started reading up a bit on "Exercise induced hangover", and found some information about Hyponatremia. It seemed that if I just digest some more salt I will be better. It worked sometimes, but still other times didn't work at all.

When the symptoms where bad I couldn't eat or drink anything for a day, or sometimes even several days. It just felt like a really bad hangover that lasted far too long.

Then I read about balancing the extra intake of sodium with potassium.

This worked a little better, but I still had serious problems about once every month. I drank a lot of sports drink, both homemade and commercial, after work out. I tried adding pinches of salt to my water. I went to see a sports doctor who hade an idea that it might be migrane, but didn't find anything pointing in that direction either...

But a small article in Runners World got me in the right direction.

I don't remember the exact words, but more or less: The amount of sodium in your sweat is actually less than in your bodily fluids as a whole. That means that when you're sweating, you are actually increasing the sodium ratio in you body! You cannot get Hyponatremia from sweating, it's the water intake afterwards that causes the problem.

So what should you drink after training to avoid hyponatremia?

Well, according to this studie:

Although it is difficult to rule out some effect of the type of fluid consumed on the risk of hyponatremia, our findings suggest that the contribution of the type of fluid is small as compared with the volume of fluid ingested.

Or put another way: it doesn't matter whether you drink plain water or a sports drink, it (statistically) doesn't effect your risk of hyponatremia.

Ok, so it's neither the sweating, nor the type of drink that causes it? Then what?

Well, read the above quotation one more time:

our findings suggest that the contribution of the type of fluid is small as compared with the volume of fluid ingested.

It's the amount of fluid you drink! My kidneys can produce roughly about half a litre of urine per hour. That should mean that if I limit my fluid intake to half a litre per hour, my body will be able to get rid of any excessive water. But if I consume more than that amount, I might be in the risk of "water poisoning" myself.

I have now been limiting my water intake for the last three months and have had no problems yet.

Ok, I am quite thirsty sometimes. Only drinking a small bottle of water after a half marathon is quite hard, but I feel so much better when doing it!

And thinking about it, are any other primates drinking the amount of water that we are? I am certain that being thirsty isn't that bad, but drinking too much water is really dangerous.