Dehydration doesn’t discriminate. It can happen to elite athletes, weekend warriors, and the general inactive population alike. Symptoms can be mild to severe, and in some cases fatal.
Most people associate dehydration with being thirsty. While this is one sign that your body may be starting to 'dry out' like a grape in the sun, there are other things to be aware of that may help you stave off dehydration.
What’s more, dehydration can be classified as either acute or chronic. In this article, we will discuss the differences between the two, what to look out for, how to prevent dehydration, and how to treat it if it happens to you.
According to the American College of Sports Medicine (ACSM), dehydration simply refers to the loss of body water. However, it is a lot more complicated than that. We need to narrow our focus on exercise-induced dehydration. We’re athletes after all.
Exercise-induced dehydration refers to:
When athletes lose two percent or more bodyweight via sweating, bad things can happen. These include:
Did that last bullet point catch your attention? I hope so because dehydration is a high stakes poker game with some serious consequences if you roll the dice wrong.
Now it’s time to get down to brass tacks and discuss the different types of dehydration. Acute and chronic
Acute dehydration, as the name implies, happens in the short term and occurs when you lose more fluid than you take in. It can be summed up like this:
Fluid out > Fluid in
Acute dehydration affects the way the body functions and can inhibit athletic performance. The good news is acute dehydration is easy to spot and highly preventable
The tests for acute hydration are simple and straightforward and do not require any invasive techniques. These are:
Treating acute dehydration is fairly simple.
Generally speaking, acute dehydration can be resolved in 30-60 minutes once fluid is consumed in adequate amounts and absorbed by the body.
Unlike short-term, acute dehydration, chronic dehydration occurs when dehydration recurs over longer periods of time. For example, not drinking enough water on a daily basis (over the course of a month) to replace fluids lost through bodily functions, activities of daily living, and exercise.
If left untreated, chronic dehydration can have disastrous consequences and will require immediate medical attention.
The causes of chronic dehydration are similar to those of acute dehydration. Also included are:
There are two ways to test for chronic dehydration:
Unfortunately, just “drinking enough water” is not a cure for chronic dehydration. More than likely you will need to drink electrolyte beverages to restore fluid balance and help your body hold on to more of the fluids you are drinking.
Additionally, you may be put on a drinking schedule where fluid is measured out and consumed throughout the days at certain points.
In the most extreme cases, an IV may be needed to directly deliver fluid into your bloodstream.
Last but not least you may need to cut back on habits that caused the extreme fluid loss. This includes decreasing alcohol and caffeine consumption and cutting back on any diuretic medications you may be on.
The time it takes to recover really depends on why it happened in the first place and how long you have been chronically dehydrated. Simply put, there is not an exact number of days and will depend on an individual's circumstances.
Your doctor may perform the tests listed above over the course of 60 days to determine when you are back in a euhydrated (normal body water content) state.
The following guidelines suggested by the International Society Of Sports Nutrition should leave athletes in a hydrated state throughout the day and during exercise.
There are a lot of opinions on the best way to hydrate during exercise to prevent dehydration.
However, the two most common and research-backed methods of staying hydrated are drinking on a schedule and drinking to thirst.
Drinking on a schedule is exactly what it sounds like. An athlete consumes fluid at specific points during racing or training.
For example, taking sips of sports drink every 10-15 minutes that usually equates to 16-32 ounces of fluid per hour.
While this method is tried and true, some athletes experience GI distress from drinking too much and other times it is not practical to drink on a schedule (i.e. during a mountain bike race on rocky singletrack.
Again, this is exactly what it sounds like. It can be summed up by:
Drink when you are thirsty and don’t when you are not.
The research has demonstrated that this method is just as effective as drinking on a schedule when it comes to preventing dehydration or the 2% body weight loss from sweating.
The short answer to this is no. Besides, it is very difficult to replace every drop of fluid you lose through sweat during exercise. And that’s OK!
Even if you drink on a schedule or drink to thirst, more than likely you will still lose body weight through sweat. This shouldn’t have a negative impact on performance if you are following the hydration strategies outlined above.
There are a lot of variables that can determine how quickly an athlete can become dehydrated. These are discussed below.
Use the following formula to get an idea of your hourly sweat rate:
16 x [(your starting weight in-lbs) – (weight in-lbs after 1-hour of exercise)] + [fluids consumed during exercise in oz] = sweat loss in oz/hour.
Say for example I weigh 161 pounds before exercise and 160 pounds when I finish my workout. The calculation would look like this:
16 x [(161 lbs) – (160)] +  = sweat loss in ounces per hour.
16 x 1 = 16
16 + 8 = sweat loss of 24 ounces per hour
Therefore, I would try to drink 24 ounces of fluid an hour to offset the fluid I am losing through sweat.
What a morbid question. The norm is 10 days after absolutely no fluid is consumed.
More of something isn’t always better and this can be the case when an athlete drinks WAY TOO MUCH fluid before and during exercise. Especially if it is water, as this can cause hyponatremia.
Hyponatremia happens when an individual drinks too much water which throws the body’s electrolyte balance out of whack. Mild hyponatremia can lead to headaches, nausea, confusion, and fatigue while severe hyponatremia can cause comas, seizures, and death.
To avoid hyponatremia athletes should NEVER over hydrate while also consuming salty (i.e. electrolytes) foods and beverages during exercise.
So far we have discussed several conventional methods to prevent dehydration. While proper hydration and nutrition will always be your best bet to battle dehydration, there are a few supplements that may also help.
Most people think electrolytes prevent cramping. While this may be the case in rare circumstances, electrolytes play a bigger role when it comes to dehydration because they can:
Creatine isn’t just for the gym bros to get big and strong. It can help with hydration! When creatine is taken it promotes water uptake in the muscles. Properly hydrated muscles = happy muscles that perform well! 2-3 grams daily is the dose here.
Betaine helps with water retention in the cell (osmolyte) and thus protects the cell from hydration. 2.5 up to 6 grams daily.
Glycerol acts like creatine in that it helps the cells to uptake more water. 1.2 grams per kilogram body weight and 26 milliliters per kilogram bodyweight of fluid, 60 minutes prior to exercise.
Both acute and chronic dehydration can derail your athletic performance AND have a negative impact on your health.
By following the advice given above, an athlete will remain in a euhydrated (adequately hydrated) state throughout the day and before, during, and after exercise.
About The Author Matt Mosman - Spearfish, South Dakota
Matt Mosman (MS, CISSN, CSCS) is a research scientist, endurance athlete, and the founder and Chief Endurance Officer at EndurElite. Matt holds his B.S. in Exercise Science from Creighton University and his M.S. in Exercise Physiology from the University of California. Matt and his family reside in Spearfish South Dakota where they enjoy running, mountain biking, camping, and all the outdoor adventures Spearfish has to offer.