Runners and Triathletes Guide to Sweat Rate and Sodium

Nov 1, 2020 Fuel Sweat
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Overview

What Is Sweat Rate

The simplest definition is that it is the amount of fluid lost during activity.

Why Sweat Rate Matters

Understanding an athlete’s sweat rate is key to optimal performance for all endurance athletes alike. Sweat is important because it helps to cool off your body when you are exercising. If you are not able to adequately cool your body off, then you are putting yourself at risk of heat stroke. Many causes may prevent ou from sweating, so talk to your doctor. One of the most common though is that you are dehydrated due to fluid and electrolyte loss that has occurred before or during exercise.

What Is The White Stuff On My Face And Clothes

Salt! When your body sweats, it’s not just water that you are losing. It’s electrolytes like salt too. Rehydrating is important, but it’s also important to get electrolytes. If you don’t, then you are at risk of hyponatremia. Hyponatremia is a serious condition that can lead to dire consequences. If you think you are experiencing hyponatremia, seek EMERGENCY MEDICAL ATTENTION. Symptoms may include:

  • Nausea with vomiting
  • Fatigue
  • Headache or confusion
  • Cramps or spasms in your muscles
  • Irritability and restlessness
  • Weakness
  • Vomiting or nausea
  • Confusion

How To Calculate Sweat Rate

To calculate this, weigh yourself before a run/ride and then again after. From there, find the difference between the two and factor in how much fluid you took in during the activity.

For example:

  • Before my run: 180lbs
  • After my run: 178lbs
  • Activity duration: 2hrs
  • Amount of liquid consumed: 32 ounces

The Math:

  • 180 - 178 = 2 lbs
  • 2lbs + 2lbs consumed (32 ounces) = 4lbs
  • 4lbs / 2 hours = 2lbs (32 ounces)

32 ounces per hour sweat rate

How To Calculate Sodium Loss

The easiest way to do this is to pay someone to do it for you unfortunately. There are a ton of places that do this, but if you google search “Sodium Concentration Testing” then you should be able to find one near you. Upon completion of testing, they will be able to tell you how much salt you have to replace in a given hour in addition to your sweat rate.

Popular electrolyte supplements include:

  • Gatorade / Gatorlytes
  • Nuun Tablets
  • Coconut Water
  • Pedialyte
  • Skratch Tablets
  • Saltstick Caps
  • BASE Salt
  • Pickle Juice (yes, pickle juice)
  • Bouillon (or my favorite Better than Bouillon)

FYI, this is not an ell encompassing list. New supplements are being created all the time.

Do I Need To Hydrate When Swimming

Yes! Just because you are in water doesn’t mean that your body doesn’t lose sweat.

Do I Need To Hydrate During The Winter Months

Yes! Just because it is cold out doesn’t mean that your body doesn’t lose sweat as well.