Hydration and Nutrition FAQ

Rebecca Youngs, MS, RD, LD

Fit For Life Physical Therapy

Question: “After my running or walking workout I see white streaks of salt residue on my arms and legs – and even my clothes.  Why?”

After reading the article last week on hydration, this might make a little more sense, but let us dive deeper.  If you taste salt in your sweat, feel dry or gritty after a run, or see white streaks on your body, you are a salty sweater… meaning you have much higher sodium needs than the runner next to you. 

Sweat evaporates through our skin as it is well-established that the primary physiological function of sweating is to disperse heat to regulate body temperature.  With sweating, heat is transferred from the body to water on the surface of the skin, especially when exercising to cool down the body.  Although there are many electrolytes in sweat, sodium and chloride contribute to the biggest losses when sweating.  

Causing substantial changes in sodium concentrations in the body by either drinking too much water, or from losing too much salt (more likely in some than others) can be dangerous from a neurologic standpoint and can also lead to muscle cramps that can hinder performance.  All athletes should use electrolyte-rich beverages during training, as well as throughout that day if a great deal of fluid was lost.  

Athletes who notice the salt residue on their skin should pay more attention to replenishing their sodium stores via electrolyte beverages with higher sodium concentrations, snacking on salty foods, using condiments high in sodium like soy sauce and ketchup, salting food liberally, or using salt sticks.  Some medications may also influence the rate of sweat loss.  

If an athlete frequently experiences muscle cramps or notices these signs of excessive sodium loss, working one on one with a dietitian can be helpful in assessing the actual amount of sodium lost in a period of time and the best way to replenish these stores to help improve performance. 

Question: “After a hot run or walk, I notice a vinegar smell.  Is that normal?”

This “vinegar” smell you may notice after a hot, sweaty run is actually ammonia, a byproduct of protein break-down.  Normally, when proteins in the body are broken down, ammonia is generated and is excreted via the liver and urine.  But, when the body is producing more ammonia that usual, the only other place to excrete it is in sweat.

So why would a runner or walker breakdown protein during or after a hard workout?  Because protein is being broken down to supply the body with glucose for energy.  If the body does not have an adequate glucose supply or enough stored glycogen to fuel the activity, the body will breakdown protein. 

This is NOT what we want as athletes!  To prevent this, increase your daily consumption of carbohydrates, as well as your hydration efforts.  Most of the time, this is unintentional and is due to athletes not knowing how many carbohydrates they need.  But, if an athlete is intentionally cutting carbs, the body will continue to break down muscle to get glucose which can become dangerous and severely impair performance.  There may be other medical conditions or infections that can cause a vinegar-like odor when sweating.  Please work with a medical professional to determine if other items may be the cause, or if you are not eating enough carbohydrates!

Registered & Licensed Dietitian Rebecca Youngs is an avid marathoner, loves to work out, and has specialized her practice in gastrointestinal health, as well as sports nutrition and fueling athletes of all levels. She is available for individual consultations at Fit For Life Physical Therapy or through zoom video conference.

Fit For Life Physical Therapy cares for people of all activity levels - to help prevent, recover from, or rehabilitate sports & orthopedic injuries.  We are proud to move people every day.

Please visit our website https://www.fitforlifephysicaltherapy.com/, email us at info@fitforlifephysicaltherapy.com, or call or text us at any of the phone numbers for our three convenient locations inside Fleet Feet/FrontRunner stores:

Polaris:  1270 East Powell Road Lewis Center, Ohio 43035 ~ 614-981-2065

Upper Arlington:  1344 West Lane Avenue, Columbus, Ohio 43221 ~ 614-981-1979

New Albany:  5792 North Hamilton Road, Columbus, Ohio 43230 ~ 614-581-7441