How Much Water Do You Really Lose During A Workout?

Now, this is a tricky question but let’s dive in.

To figure out the amount of water you lose during a workout depends on several factors.

Your sweat rate can vary based on the activity, the temperature,humidity, what shape you’re in and even the clothes you’re wearing.

Sweating occurs as your body breaks down fuel to create energy for your tissues to use causing your core temperature to rise. Your body then releases heat in the form of water as a response to this temperature elevation in an attempt to cool your body.

When you’re dehydrated, your body cannot undertake this process as efficiently which leaves you susceptible to heat related injuries or symptoms.

The average person will sweat between 0.8 and 1.4 liters (which is roughly 27.4 to 47.3 oz.) per hour during exercise.(To give you an idea of how much that is, larger water bottles hold around 24 oz. of water.)

This can mean different things in terms of % of body weight. A safe percentage of body weight lost during exercise due to fluid loss is anywhere from 1-2%. Anything more than that and you are experiencing dehydration, which means less than optimal performance.

If you are not losing any body weight percentage, then you are taking in too much additional fluid.

0.8 to 1.4 liters is a wide range so we suggest you use a sweat rate calculator like the one here to find out your individual sweat rate or you can simply measure your sweat rate by weighing yourself before and after exercise. Keep in mind you need to factor in any fluids lost (bathroom breaks) or fluids taken in during exercise.

Finding out your sweat rate is extremely important for exercise prep and rehydration. Hydration is the difference between outstanding and poor athletic performance.

To properly hydrate before and after exercise, you should know your hydration rate as well.

You can find a handy hydration calculator here that tells you approximately how much fluid you should take in per hour based on your individual specifications and exercise.

Note: when we talk about hydration and re-hydration we do not mean that you should only take in water. If you are exercising in extreme conditions or for a lengthy amount of time, your body requires a small amount of sodium so that you do not experience hyponatremia, which occurs when you have taken in too much water and not enough sodium, resulting in nausea, headache and fatigue.

We suggest consuming water/ water with electrolytes before exercise and suggest rehydrating with a variety of foods and liquids. Several fruits and veggies have high water content. You can also find high water content in smoothies.

At SmoothieCompany.com for example, our smoothies are made with 16-24oz of Ice, real fruit smoothie puree, protein powder plus an additional 3-6oz. of water making our smoothies the perfect post-workout drink to help refuel muscles, replenish glycogen stores and rehydrate your body.