By Holley Samuel MEd, RD, LD, CPT
Sodium (salt) and electrolyte consumption can be a very confusing topic for runners, as many athletic nutrition recommendations contradict the general nutritional advice provided to the majority sedentary population. Sodium is an electrolyte that aids in maintaining fluid balance in the body. This electrolyte can help runners stay hydrated and keep muscles contracting and relaxing appropriately during exercise and at rest.
When public health sources make generalized nutrition recommendations to the public, they are usually talking to the ~99% of the American population who are not endurance athletes.
When runners, regardless of experience, take advice from most general public resources, they can set themselves up for health issues that may negatively affect athletic performance and wellness beyond sport. Sodium is just one example of a nutrient endurance athletes need to consume in higher quantities than the general population.
Determine Daily Sodium Consumption
Initially, athletes should identify how much sodium they consume each day through food, supplements, and drinks to help them determine their electrolyte strategy.
"The general American population tends to consume 3,400mg sodium per day on average, which is more than the recommended daily amount (RDA) of sodium per day of 2,400mg."
In some cases, athletes who may be health conscious primarily consume whole foods with minimal sodium. If this is the case, the athlete may need to salt their food or add an electrolyte supplement to meet their electrolyte needs. If an athlete finds they are consuming enough sodium in their diet and pre, during, and post-exercise, they do not need to be concerned about supplementing with extra sodium.
All endurance athletes should consider their sodium needs during exercise individually and work to consume at least 300-600mg sodium per hour in addition to meeting fluid, and carbohydrate needs as recommended by ACSM guidelines.
Signs and symptoms of electrolyte (sodium) imbalances may include:
salt crystals forming on the surface of the skin following exercise
cramping and weakness in muscles
shortness of breath
confusion, nausea, and/or vomiting
irregular color or frequency of urination
swelling in hands and fingers
Sodium Needs for Endurance Athletes
Professional Ultramarathoner ~ Hillary Allen @hillygoat_climbs
Endurance athletes lose a tremendous amount of sodium through sweat. While the general consumption recommendation is 300-600mg of sodium per hour, in hotter climates or during intense efforts, some athletes may lose up to 2,300mg of sodium per hour, which is near the recommended daily amount (RDA) of sodium intake advised by most general health resources.
In hot climates or during intense efforts, some athletes may lose up to 2,300mg of sodium per hour
Athletes who do not consume enough sodium during training will increase their risk for complications from dehydration, such as falling flat during workouts, increased risk of injury, or increased risk of a serious medical condition called hyponatremia. "Hyponatremia results from the inability of the kidney to excrete a water load or excess water intake" ~ NIH
"If fluid loss amounts to more than 2% of the body weight during exercise, runners may experience decreases in performance and become more at risk for associated dehydration symptoms."
Concerns about Consuming too much Sodium
Because of sodium's effect on fluid balance and blood pressure, it can become a nutrient of concern for the general public looking to optimize performance and health.
If someone has hypertension, the recommended daily sodium intake typically drops to 1500mg. Consuming more sodium than the body requires can increase the risk of high blood pressure, a concern for many Americans. For this reason, many athletes may be concerned about their sodium intake and even avoid higher sodium sports nutrition products or salting their food, which may also impact performance and wellness.
It's essential to consult with a registered dietitian before making any significant dietary changes to avoid complications regardless of athletic pursuits.
Current dietary guidelines. Top 10 Things You Need to Know About the Dietary Guidelines for Americans, 2020-2025 | Dietary Guidelines for Americans. (n.d.). Retrieved June 21, 2022, from http://dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials/top-10-things-you-need-know-about-dietary
Lau, W.Y., Kato, H. & Nosaka, K. Effect of oral rehydration solution versus spring water intake during exercise in the heat on muscle cramp susceptibility of young men. J Int Soc Sports Nutr 18, 22 (2021). https://doi.org/10.1186/s12970-021-00414-8
Sodium and Food Sources. CDC. (n.d.). Retrieved June 21, 2022, from https://www.cdc.gov/salt/food.htm#:~:text=Americans%20consume%20an%20average%20of,mg)%20of%20sodium%20each%20day.&text=But%20the%202020%2D2025%20Dietary,of%20a%20healthy%20eating%20pattern.
Veniamakis E, Kaplanis G, Voulgaris P, Nikolaidis PT. Effects of Sodium Intake on Health and Performance in Endurance and Ultra-Endurance Sports. Int J Environ Res Public Health. 2022 Mar 19;19(6):3651. doi: 10.3390/ijerph19063651. PMID: 35329337; PMCID: PMC8955583.
Vitale K, Getzin A. Nutrition and Supplement Update for the Endurance Athlete: Review and Recommendations. Nutrients. 2019 Jun 7;11(6):1289. doi: 10.3390/nu11061289. PMID: 31181616; PMCID: PMC6628334.