All athletes have experienced dehydration. Sometimes it is mild and it is easy to recover fluid losses post training session. Some athletes have experienced more severe consequences of dehydration including the need for IV hydration after a race or needing to be hospitalized. Training or racing without proper hydration can contribute to poor performance, loss of concentration and even heat stroke. Many athletes think of hydration as drinking enough water but adequate intakes of electrolytes such as sodium, potassium, magnesium, chloride and calcium are also critical. Because sweat losses of potassium, magnesium and calcium are low, sodium (salt) is generally the electrolyte of most concern. Just as sweat rates can vary, so do sweat electrolyte losses. Salty sweaters are most likely to run into trouble than non-salty sweater. Have you ever finished a workout on a hot dry day and noticed a white salty grime lining your face? You may be a salty sweater. Not having enough sodium in the diet or drinking too much water and not replacing electrolytes can cause the sodium levels in the body to become diluted. The medical term for this is hyponatremia.
I have experienced hyponatremia after completing a training run on a hot, humid day. I came home feeling nauseated with a headache and extreme fatigue. Luckily I knew the side effects of low sodium which can also include confusion or muscle fatigue. Extremely low sodium levels can also have severe consequences including seizures, unconsciousness, or even coma.
So what can you do to make sure you are getting enough electrolytes? For any exercise lasting about an hour or less there is probably no need to worry and most people get enough sodium in food and fluids consumed throughout the day. If you are training longer then an hour in a hot or humid environments, here are some things you can do to ensure you are keeping your electrolytes and fluids in balance:
1) Unless you have high blood pressure don’t limit sodium in your diet. Most endurance athletes don’t need to pay attention to the recommendations to limit sodium to <2000 milligrams per day. For athletes with large volumes of training/exercise in hot or humid environments this is not a good recommendation to follow. This may mean you need to add sodium to foods or consume salted foods throughout the day to get enough sodium. Salty foods also increase thirst, which can also help with hydration.
2) Drink electrolyte containing beverages during exercise. For exercise lasting longer than 60-90 minutes an electrolyte beverage containing carbohydrate is recommended. Over-drinking without electrolytes can cause low sodium because sodium levels in the body can become diluted.
3) After your workout drinking water to replace fluid losses is good, but too much water without enough electrolyte can also lead to low sodium levels in the body. This is especially true if not enough electrolytes were taken in during exercise. After hot workouts I sometimes add a pinch of salt to my recovery drink or smoothie. You can also eat a meal high in sodium. I have know athletes that drink chicken broth after a workout (not the low sodium variety). Make sure you do whatever works best for you.
4) Pay attention to the signs of low sodium. If you find that you are feeling a loss of concentration, fatigue, headache or nausea an hour or two after a workout you might be experiencing electrolyte imbalances or low sodium.
There are many factors that can effect sweating rates and sweat electrolyte losses and there is no one size fits all prescription for fluid and electrolyte consumption. I advise working with a sports dietitian to determine your individualized fluid losses and electrolyte needs during exercise.