By Holley Samuel MEd, RD, LD, CSSD, CPT

This can be a very confusing topic for runners, as many nutrition recommendations actually contradict general nutritional advice provided for a more sedentary population.

Less than 1% of the American population has completed a marathon in their lifetime. You do not need to complete a marathon to be considered a runner or active person, of course, but 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.

This can be very confusing for runners, as many sports nutrition recommendations actually contradict general nutrition recommendations for a more sedentary population. When runners and endurance athletes take advice that is not meant for them, this can set them up for other issues. Sodium is one example of a nutrient that runners may need more of than the general population.

Sodium Needs For Americans

Sodium is an electrolyte, which helps control and maintain fluid balance in the body. This can help runners stay hydrated and keep muscles contracting and relaxing appropriately during exercise and at rest. Because of sodium’s effect on fluid balance and blood pressure, it can become a nutrient of concern for runners looking to optimize their performance and health.

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. If someone has hypertension, their recommended daily sodium intake drops to 1500mg. Consuming more sodium than the body requires can lead to increased risk of high blood pressure, which is a concern for many Americans. For this reason, many runners can be concerned about their sodium intake because of the effects they hear about it having on blood pressure, and even avoid higher sodium sports nutrition products or salting their food.

Sodium Needs for Endurance Athletes

Endurance athletes exercise regularly and lose a lot of sodium through sweat. It is recommended that endurance athletes take in between 300-600mg sodium/hour during exercise, especially in hotter climates and longer training sessions where sweat loss is greater to maintain their hydration status. Some athletes need even more sodium, perhaps even up to 2,300mg per hour, depending on their individual sweat composition.

Since many athletes can lose up to the RDA for sodium in a 1+ hour training session alone, their overall sodium and electrolyte needs will be higher than what is generally recommended for the sedentary American population. Athletes who do not take in enough sodium will increase their risk for complications from dehydration such as headaches, falling flat on workouts, increased risk of injury or muscle cramping, decreased appetite, nausea, swelling of the fingers, or even a serious medical condition called hyponatremia. If more than 2% of bodyweight is lost during exercise, athletes will start to experience decreases in performance and become more at risk for associated dehydration symptoms and even more serious conditions.

How much sodium is enough?

Athletes should identify how much sodium they are consuming each day through food, supplements, drinks, or via salting their food to help them determine how to fine tune their electrolyte strategy. In some cases, athletes who may be health conscious consume whole foods primarily in their diets that contain very minimal amounts of sodium. If this is the case, the athlete may need to salt their food or add an electrolyte supplement in order to meet their electrolyte needs.

If an athlete finds they are consuming enough sodium in their diet and pre, during, and post exercise to rehydrate, then they do not need to be concerned about supplementing with extra sodium. All 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. Sodium intake outside of the workout may be considered separately.

Athletes who struggle with kidney dysfunction, hypertension, fluid retention, or cardiovascular issues should consult a sports dietitian to help them identify what amount of sodium is appropriate for them to maximize performance and keep in mind specific medical conditions. Individuals with these conditions still need to meet their electrolyte and hydration needs during workouts, but sodium intake outside of exercise sessions may be considered separately.

Sources

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.

How much sodium is too much for runners?