The Rock ‘n’ Roll Marathon in Vegas was this past weekend, and with thousands of athletes taking part in the 10k and half marathon, dehydration was a common problem seen by Dr Carfagno and his medical team. As all athletes know, maintaining the balance between fluid hydration and salt intake is essential to performance and overall health.
National recommendations for sodium intake are generally targeted towards sedentary individuals. Remember sodium is hidden in a lot of foods and should be limited in individuals with high blood pressure or certain heart conditions. U.S. Dietary Guidelines recommend for non-athletes to consume no more than 2,400 mg sodium/day. Most Americans easily consume 3,000 to 5,000 mg daily, primarily through processed foods and fast food diets.
Athletes who follow these generalized recommendations may be putting themselves at risk for decreases in performance or even serious health consequences. Those who are at a higher risk for developing hyponatremia (low sodium concentration in the blood) include slow marathoners especially who stop and drink at every water station, small stature. As you sweat during a vigorous activity, you lose not only water but also salt. Replacing both are needed to avoid muscle cramping, headaches, nausea and other side effects of possible dehydration and heat related conditions.
One suggestion to ensure you are replacing your fluids and salt depends on your sweat level and duration of activity. For example, your fluid intake should be roughly 8 oz. per 20 minutes for a 4-5 hour race, or 4-6 oz. per 20 minutes for a race greater than 5 hours. The Institute of Medicine determined that an adequate fluid intake for men is roughly about 13 cups (3 liters) a day and about 9 cups (2.2 liters) for women a day. Remember that if you are a heavy sweater during activity or participating in a high endurance sport you will likely need to supplement with additional fluids and salt.
Sponsored by Gatorade Sports Science Institute, the Sports Science Exchange offers advice and guidelines for athletes in how avoid hyponatremia and dehydration as well as specific supplementation that can be used both during training and for day-of activities. Check it out here: http://www.gssiweb.org/en/sports-science-exchange/all
Disclaimer: Articles are based on real cases seen at Scottsdale Sports Medicine. The information on this site is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this web site is for general information purposes only. Please consult your medical professional for individualized healthcare.
Institute of Medicine. Sodium Recommendations. Retrieved from http://www.cdc.gov/salt/sodium_iom.htm
Gatorade Sports Science Institute. Hyponatremia in Athletes. Retrieved from http://www.gssiweb.org/en/sports-science-exchange/all
Hew, T.D., J.N. Chorley, J.C. Cianca, and J.G. Divine (2003). The incidence, risk factors, and clinical manifestations of hyponatremia in marathon runners. Clin, J. Sports Med. 13:41-47.