Endurance athletes talk a lot about carbohydrates. Few talk about sodium.
During long training sessions and races, carbohydrate intake is essential to maintain energy availability. However, focusing only on carbohydrates can compromise performance.
Sodium replacement is just as important as carbohydrate intake to maintain performance, fluid balance and physiological stability.
The Role of Carbohydrates in Performance
Carbohydrates are the main source of energy during moderate to high intensity exercise.
In endurance sports, there is a high rate of carbohydrate oxidation, muscle glycogen is progressively reduced and exogenous intake helps sustain intensity.
Without adequate intake, early fatigue occurs.
However, energy is not the only factor that limits performance.
The Role of Sodium in the Body
Sodium is the main electrolyte lost through sweat.
It is essential for maintaining plasma volume, fluid balance, intestinal glucose transport, muscle contraction and neurological function.
When there is significant sodium loss without adequate replacement, reductions in blood volume, increased perception of effort, decreased performance, higher risk of cramps and electrolyte imbalance may occur.
Why Carbohydrates Alone Are Not Enough
Consuming carbohydrates without maintaining electrolyte balance can limit absorption and compromise the overall nutritional strategy.
Sodium plays a role in glucose transport through the SGLT1 cotransporter in the intestine. This means that the presence of sodium supports efficient carbohydrate absorption.
In addition, reduced plasma volume affects heart rate, thermoregulation and the ability to sustain exercise intensity.
In other words, energy without electrolyte balance does not sustain performance for many hours.
How Much Sodium Is Needed in Endurance?
Requirements vary according to race duration, intensity, temperature and individual sweat rate.
In long events, cumulative sodium loss can be substantial. Therefore, the strategy must be planned and structured.
Replacement should be consistent rather than reactive.
According to a 2022 review published in the International Journal of Environmental Research and Public Health, adequate sodium intake plays a relevant role in health, maintenance of fluid and electrolyte balance and performance in endurance and ultraendurance athletes, reinforcing that nutritional strategies should not focus only on macronutrients but also consider electrolytes as a central component of performance.
Common Mistake in Nutritional Strategy
A frequent mistake is calculating only grams of carbohydrate per hour.
An ideal strategy considers carbohydrate targets per hour, sodium replacement planning, distribution throughout the event and gastrointestinal tolerance.
Sustained performance depends on the combination of these factors.
Conclusion
In endurance sports, carbohydrates and sodium work together.
Carbohydrates provide energy. Sodium maintains the physiological environment that allows this energy to be used efficiently.
Neglecting sodium can compromise a well designed carbohydrate intake strategy.
A complete approach considers energy availability and electrolyte balance as inseparable pillars of performance.
Reference
Veniamakis E, Kaplanis G, Voulgaris P, Nikolaidis PT. Effects of sodium intake on health and performance in endurance and ultraendurance sports. International Journal of Environmental Research and Public Health. 2022;19(6):3518.
