Overhydration

We are all familiar with how important it is to hydrate, and you’ve probably been told by a medical provider that you have to hydrate more. However, there is such a thing as too much. As with everything in the body, it’s all about balance.

The balance, in this case, is all about electrolytes and water. The body is a bioelectric machine and requires the right balance of fluids to conduct signals like nerve impulses that create muscle contraction. When you eat and drink, the body takes what it needs to keep this balance, and then excretes the rest out. You can easily see this after a salty meal when you urinate. That’s the body dumping out the excess salt. Conversely, if you haven’t had enough salt, the body will excrete more water and your urine will be clearer. 

Dehydration has its risks and you won’t live long without water. However, overhydration can be just as deadly. When you gulp down tons of water prior to a sporting event thinking that it’s a good thing, you can develop hyponatremia. That means that you’ve diluted the fluids and now you don’t have enough salt. Under normal circumstances, the body would just eliminate some water and restore balance. However, if you are a distance runner, you likely are not going to stop to pee. Then if you continue to hydrate, you could get yourself into some trouble. 

Water in the body resides both inside a cell (intracellular), and outside the cell (extracellular). The extracellular fluid is primarily in blood plasma, with a small amount residing in the lymph. About ⅔ of the water is in the intracellular fluid and ⅓ in the extracellular fluid. When you are overhydrated, in an attempt to restore electrolyte balance, water will move from the bloodstream into the cells. This will lead to puffy fingers and toes, and even worse, it can cause hydrocephalus. This means swelling in the brain, and it can be deadly. 

There have been many instances of runners collapsing and dying from overhydration, and many more hospitalizations. So how do we know how much water to drink? This is a complicated question and depends on many factors, such as the type of sport, conditioning levels, male vs. female, body weight, sweat rate, environmental heat, etc. There are some symptoms that will clue you into the early signs of hyponatremia. If your wedding ring is feeling tighter, that’s a sign you have too much fluid retention. Other signs include confusion, cramps, vomiting, and headache. If it goes on for too long, one could go into a coma, have seizures, and even die. 

Part of the issue is that we’ve been told how important it is to hydrate, however this may be an overcorrection and there is a history behind it. In the 1900’s, athletes were told not to drink during a sporting event. Then in the 1960’s, gatorade was invented by a physician at the University of Florida that improved performance for their football team. A whole industry was born around rehydration. As humans do, we overcorrected to the point where many athletes are now overhydrating (thanks to Precision Hydration for the history summary). There are lots of recommendations out there for strategies to optimally hydrate, but bearing in mind all the individual differences we have and all the factors that go into fluid balance, there is no one size fits all answer. Precision Hydration is an organization that has a free online test you can take to give you an idea of what you may need and will even give you a hydration plan. Check it out here.