Q and A – Over Hydration

A few weeks ago I had a question from one of our followers Taz VanLeeuwen –

Dehydration is often discussed but what is over hydration and how do you find the right balance?

Great question Taz and a very important one. Many people are told about how important hydration is without being informed of the hidden dangers of over hydration. In fact, over hydration (hyponatremia) is far more dangerous and deadly than dehydration. If someone is dehydrated, it’s quite easily fixed, you can just give them more water, or in extreme cases a qualified paramedic can hook you up to a drip and problem solved. If you are hyponatremic, it can sometimes be misdiagnosed as dehydration, therefore treated incorrectly, and even if diagnosed correctly is far harder to treat than dehydration.

In a nutshell, hyponatremia is an excess dilution of electrolytes (mostly sodium) in the blood which causes many of the bodies essential functions to slow down or cease working and in extreme cases, death. The only way to overcome it is to supply the body with the electrolytes it needs. But as with many things, prevention is far better than a cure.

So let’s focus on preventing this from happening. If you tke the recommendations from a number of years ago, you should drink 1.2 liters of water and 600ml of sports drink per hour. Now I’m guessing these people have never run anything longer than a few k as most of you would know, with this amount of water on board, you would be running off to the bushes ever few minutes to relieve yourself. Not to mention the bloated stomach!

Believe it or not, drinking during events is actually a new thing with the elite Marathon runners of 30+ years ago not drinking during events. So drinking heaps in races shorter than this is simply not necessary. Especially if you are towards the back of the pack where most of these issues tend to occur. More recent studies have shown that the body will struggle to process more than 500ml of water per hour for the average person. This is obviously dependant on temperature and humidity with higher levels required when it is hotter or more humid, but it is a good point to start from. In some conditions, depending on the intensity of the race, it is impossible to replenish all the fluid we lose, so all we can do is try to replenish what we can and slow down if dehydration does start to become a factor.

What I would recommend you do is listen to your body. Previous recommendations state that you should drink before thirst kicks in. But thirst is a great tool to keep track of things. If you are running well and not thirsty, maybe just have the occasional sip of water. If you notice yourself getting overheated and lethargic, maybe your water intake should be increased (excluding fuelling issues). Remember there is no exact science to this. Each person is different and each race will have its own unique conditions.

Now getting electrolytes right is something that is quite easy to do with so many sports drinks and gels on the market. You really have no excuse to come close to hyponatremia. First thing you can do is add a small pinch of a high quality sea salt to you drink bottles. This will work in a couple of different ways. Organic substances actually increase our absorption of water, so will help hydration, while the salt is predominantly sodium, one of our most important electrolytes. You shouldn’t be able to taste the salt, but the water will have a slightly different feel in the mouth. If you can’t tolerate that, there are products out there that are salt in a capsule which can work really well as you don’t have to taste it at all.

Most gels contain an element of sodium, so having a gel every hour and a good mouthful of water with it (essential for the absorption of the gel) is a great start. Even the amazeballs from The Runners Kitchen which I use quite often contain an element of salt. So you have many choices as to how you want to tackle this problem.

So to summarize this –

• Drink to your thirst, there is no need to drink more than your body tells you it needs.

• Use a salt supplement, either a pinch of sea salt in your water or use a salt supplement in a capsule once an hour, especially in ultra distances.

• Use an electrolyte drink, gel or solid fuel like Amazeballs every hour at least to help keep your electrolytes up.

• Lastly, monitor your urine output and colour. If you are having to go every hour and it is clear, you may be drinking too much and if it’s been many hours since you last went and it is dark when you do go, start drinking!

It’s definitely not an exact science and is something you can try out during your training runs. Just check how your thirst is after your long run for the week and work out how much water/electrolytes you tend to need. By the time you get to a race, there should be no questions left unanswered.

Hope this helps clear up a few things Taz,

Run Well

Chris O’Driscoll

P.S. If you have any questions you would like cleared up, feel free to email me at chris@brewstersrunning.com


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