Hydration feels like a very simple concept – drinking water before, during, and after a workout is the key to ensuring that you don’t suffer from dehydration while working out. But sometimes, it can be hard to figure out why it’s such a big deal. Here’s why hydration is so important during a workout. 

Adverse Effects of Dehydration

Dehydration is no joke – it can lead to decreased coordination, fatigue, headaches, muscle cramps, and nausea. Being hydrated is also critical for preventing heat-related illnesses such as heat exhaustion or heat stroke, which can have serious consequences if you let them progress too far.

Additionally, studies have shown that decreased hydration can impair your performance and prevent you from getting the most out of your workout. 

How Much Should You Be Drinking?

While there are a ton of different guides out there stating how much you should be drinking, the current science on the matter is very simple: drink when you’re thirsty. This method can prevent you from under- or over-hydrating. If you’re searching for a little bit of a guideline, a good rule of thumb is to drink 4 to 6 ounces of fluids every 20 minutes while working out. If your workout lasts 90 minutes or more, include a sports drink to replace lost sodium and minerals as well as water.

While these tips are fairly broad, your fluid intake needs will vary depending on your sweat rate. Most people sweat between one and four quarts per hour. To determine what your sweat rate is, weigh yourself nude before and after a timed workout. If you drink during that workout, be sure to track how much and add this to your calculations. Each pound of lost weight equals a pint of water loss.

Using this calculation, you can determine what your fluid needs will be during a given intensity of activity.