During long runs, especially in hot and humid conditions, your body sweats out not just water but also vital electrolytes, including sodium (sodium chloride). Sodium is crucial for maintaining fluid balance, nerve function and muscle contractions. In extreme cases, losing too much sodium through sweat without replacing can hyponatremia, a dangerous condition where your sodium levels become very low. Salt tablets are designed to help replace the sodium lost during prolonged physical activity, preventing electrolyte imbalances that can lead to muscle cramps, fatigue and even more severe issues.
How much do you need?
The amount of sodium you need during a long distance will vary widely depending on factors such as your sweat rate, the race conditions, and your individual physiology. On average, runners lose about 500 to 1,500 milligrams of sodium per litre of sweat. However, research suggests that the need for salt supplementation isn’t universal, with some studies indicating that for most runners, normal hydration with electrolyte-rich fluids is sufficient to maintain balance. Salt tabs may be more useful for people who sweat heavily or those running in extreme heat, where sodium losses are more pronounced. It’s also crucial to remember that taking too much sodium can lead to gastrointestinal issues or increased thirst, so tailoring your intake to your specific needs is essential.
Finding the right balance
If you decide to use salt tabs during your ultra, it’s essential to experiment with them during training rather than on race day. Start by understanding your sweat rate—some experts suggest weighing yourself before and after a run to gauge how much fluid and sodium you’re losing. From there, you can determine whether you need to supplement with salt tablets and in what quantity. Typically, athletes might take one salt tab every 60 to 90 minutes during a marathon or ultra, but this can vary widely. Listen to your body, monitor how you feel and adjust your strategy as needed.
Salt tabs can be a useful tool to consider if you’re tackling endurance events. but they’re not a one-size-fits-all solution. Understanding your body’s needs, the conditions of your race and the science behind sodium balance can help you decide whether they’ll help your performance on race day.
