Is your sweat rate negatively impacting your health and performance?

 

As the weather gets warmer, I often get emails from athletes asking me about my recommendations for sweat testing or if I can review sweat test analysis. Interestingly, almost every time I speak with an athlete in regards to sweat rate and sodium loss, they give a lot of focus to sodium. While sodium is important and plays a role in sport drinks (and in your daily diet), you can't load your body with sodium and expect your body to perform well if you are exercising in a dehydrated state.

The sweating response is a thermoregulatory mechanism designed to help cool down the body. Dehydration increases in hot conditions. Dehydration occurs from sweat loss. When you sweat you lose fluids. If you don't replenish these fluids as you are exercising, your blood volume drops, which causes your blood to get thicker. This makes it harder for your heart to supply blood to your muscles. As a result, your heart has to work even harder to pump that blood. Additionally, when fluid levels drop, you have a harder time controlling body temperature which causes the core temperature to rise even faster.

You are going to lose more fluid through sweating when your body gets warm. But you DO NOT lose sodium without fluids. Dehydration is fluid and sodium loss - not directly from sodium loss. If you are simply focusing on sodium, but not drinking enough water (fluid) each hour, the sodium will not benefit your high sweat rate.

You must drink enough fluid - in the right combination/formulation of sodium and carbohydrates - for those nutrients to be properly digested and absorbed, in order to keep you properly hydrated and fueled. 

When it comes to understanding your hydration needs in order to devise a personalized hydration and fueling plan, you need to take into account the following: how much fluid you are loosing each hour (ex. your sweat rate—usually measured ml/hr) and how much sodium you’re losing when you sweat.

You can't just focus on sodium and neglect water (and carbohydrates). They all work together to keep your body performing well and to stay in good health. 

To help keep your body functioning well as you advance your training en route to your upcoming endurance events, do the following:

• Keep yourself well-hydrated during the day. ~90 ounces of fluid for women, ~120 ounces of fluid for men.
• Rehydrate after sweaty workouts: ~16-20 ounce water + pinch of salt
• Follow well researched, practical sport nutrition and hydration guidelines before/during and after workouts.
• Do..... not ration your fluids to minimize stopping or try to "save weight" when biking by limiting how much fluids you have on your bike. 
• Make sure you are comfortable drinking while moving (ex. biking, running, between sets while swimming).
• Wear a hydration belt/pack everytime you run outside. I love my Naked Running band. Karel likes this belt (PYFK Running Belt Hydration Waist Pack with Water Bottle Holder)
  as well as the one he has from Compress Sport.
• There are a variety of sport nutrition powders on the market to help you take away the guessing to ensure you are meeting your needs. As a reminder, gels and chews are sodium low, concentrated sources of carbohydrates. If you are prioritizing gels, chews and solid food over sport drinks, you are likely falling short on your sodium and fluid needs.