First of all, sweat contains electrolytes and the main electrolyte lost in sweat is sodium, although how much each individual loses through sweat varies from person to person. Electrolytes are ionic solutions (salts) that exist in the form of minerals. They play a variety of important roles in the body and are mainly comprised of:
- Calcium – which is essential for bone formation, aids in muscle contraction, blood clotting and the transmission of nerve impulses
- Magnesium - helps the body use glucose, assists in making protein and fat, and acts as a method for energy production
- Sodium – has the important function of helping to balance fluid levels in the body
Drinking only when thirsty will prevent over-consumption of fluids and is the safest way to hydrate during endurance exercise. Many runners believe that they need to “hyper-load” on fluids before race day. In reality, the body is not equipped to carry excess fluid and drinking too much during exercise can dilute the sodium content of blood to abnormally low levels which can cause hyponatremia.
Hyponatremia is an imbalance of water to salt in the body and can cause:
marathon, take the time to grab that paper cup and keep yourself consistently hydrated. This way you won’t dehydrate at the end of your run and lose out on performance.
So, all of you that will be running this weekend, have fun and keep drinking water!
References from the SIRC Collection
1. Anastasiou C, Kavouras S, Sidossis L, et al. Sodium Replacement and Plasma Sodium Drop During Exercise in the Heat When Fluid Intake Matches Fluid Loss. Journal Of Athletic Training [serial online].
2. Beltrami F, Hew-Butler T, Noakes T. Drinking policies and exercise-associated hyponatraemia: is anyone still promoting overdrinking?. British Journal Of Sports Medicine [serial online].
3. Clark N. Fluid Facts for Active Lifestyles. Palaestra [serial online]. Summer2007 2007;23(3):43-44.
4. Gibala M. DIET FOR SPORT PERFORMANCE & ACTIVE LIFESTYLE. Wellness Options [serial online]. 2005;(21):32-33.
5. Heaner M. To Salt or Not to Salt?: An update on sodium and how it affects health and exercise. IDEA Fitness Journal [serial online].
6. Webster S. do runners overhydrate on race day?. IDEA Fitness Journal [serial online]. November 2011;8(10):57.