Nutrition Diet: How to take salt tablets in a marathon?

October 31, 2025 •

4 min read

During endurance events, runners can lose over 1,000mg of sodium per hour through sweat, making electrolyte replenishment crucial. Understanding how to take salt tablets in a marathon is key for sustaining performance and preventing issues like cramping or hyponatremia.

Quick Summary

Using salt tablets effectively during a marathon requires testing during training to determine individual needs, balancing usage with adequate water intake, and considering other sodium sources. Optimal timing and amount depend on personal sweat rate and race conditions.

Key Points

Pre-Race Testing: Always test your salt tablet strategy during long training runs to prevent race day stomach issues and performance problems.
Individualized Dosing: Base your requirements on your personal sweat rate, the race conditions (heat/humidity), and the total sodium from all your fuel sources.
Hydrate Appropriately: Taking salt tablets without sufficient water can cause severe gastrointestinal distress and bloating; always consume them with plenty of fluid.
Start Early and Stay Consistent: Begin taking salt tablets early in the race, typically after the first 60-90 minutes, and maintain a consistent schedule rather than waiting for cramps to appear.
Prioritize Overall Nutrition: Salt tablets are just one component of a marathon nutrition plan; ensure you are also fueling adequately with carbohydrates and staying hydrated throughout the race.

Why Runners Use Salt Tablets

During long-distance running, particularly in a marathon, your body sweats to regulate its temperature. This sweat contains not just water but also essential electrolytes, primarily sodium. A significant loss of sodium without proper replacement can lead to several performance-impairing and health-threatening issues. The primary role of salt tablets is to provide a concentrated, portable source of sodium to replace these lost minerals.

The Dangers of Electrolyte Imbalance

Hyponatremia: This is a dangerous condition caused by an abnormally low concentration of sodium in the blood. It often occurs when runners over-hydrate with plain water and do not replace enough electrolytes. Symptoms include nausea, confusion, fatigue, and in severe cases, seizures and coma. Salt tablets, when used correctly with water, help maintain the proper sodium balance.
Muscle Cramps: While not the sole cause, low sodium levels can contribute to exercise-induced muscle cramping. Many runners report that using salt tablets helps alleviate or prevent these painful cramps during long races.
Performance Impairment: Electrolytes are vital for muscle contraction, nerve function, and maintaining fluid balance. Depleted levels can cause premature fatigue, impaired concentration, and reduced performance.

How to take salt tablets during a marathon

Using salt tablets successfully is not a one-size-fits-all approach. It requires careful planning and testing during training to find what works for your body.

1. Test During Training, Not on Race Day

Never experiment with a new nutrition strategy on race day. Incorporate salt tablets into your long training runs to see how your body responds. Pay attention to how you feel, monitor for signs of stomach upset, and adjust your intake accordingly.

2. Determine Your Individual Needs

Your sodium needs are unique and depend on several factors:

Sweat Rate: Heavier sweaters lose more sodium. You can estimate your sweat rate by weighing yourself before and after a training run under similar conditions to your marathon.
Weather Conditions: Hot, humid conditions increase sweat production and salt loss, requiring a higher intake.
Exercise Intensity and Duration: Longer, more intense runs lead to greater electrolyte depletion.

3. Consider Your Overall Sodium Intake

Salt tablets are a supplement, not your only source of sodium. Most sports gels, sports drinks, and energy chews contain sodium. Calculate your total intake by checking the labels of all your nutritional products. For example, if your gel provides sodium, you may need fewer salt tablets per hour. Many sources suggest aiming for a certain range of sodium per hour during endurance events.

4. Stay Hydrated With Water

This is a critical, non-negotiable step. Salt tablets must be taken with sufficient water to help your body absorb the minerals and prevent stomach discomfort. Swallowing concentrated salt without enough fluid can cause bloating, nausea, and disrupt your fluid balance. The amount of fluid needed per hour can vary depending on weather and sweat rate.

5. Follow a Timed Schedule

Instead of waiting for symptoms, follow a proactive schedule. Many runners develop a consistent intake plan during training. Start earlier in the race and maintain a consistent intake to avoid playing catch-up with your electrolytes.

Salt Tablets vs. Electrolyte Drinks


Feature	Salt Tablets	Electrolyte Drinks/Powders
Portability	Very easy to carry in small bags, vests, or shorts pockets.	Requires carrying bottles, a hydration pack, or relying on aid stations.
Sodium Concentration	Highly concentrated, allowing for precise, adjustable intake.	Concentrations can be fixed, making it harder to customize for varying needs.
Versatility	Can be taken with plain water or combined with low-sodium sports drinks/gels.	Delivers fluids, electrolytes, and carbohydrates simultaneously.
Stomach Impact	Can cause GI distress if not taken with enough water.	Generally gentler on the stomach, but can cause sloshing if over-consumed.

Common Types of Salt Tablets for Runners

Capsules: These are swallowed with water and provide a quick, potent dose of electrolytes. Brands like SaltStick Caps are popular.
Chews: Chewable tablets offer faster absorption and can feel like a pleasant treat on the run. SaltStick Fastchews are an example.
Dissolvable Tablets: Tabs that dissolve in water are a great way to add electrolytes to a plain bottle of water. Brands like Nuun offer a variety of flavors.

A Final Word of Caution

While salt tablets can be a valuable tool, they are not a cure-all. Pay close attention to your body's signals throughout the marathon. Symptoms of over-consumption (extreme thirst, bloating) can sometimes mimic under-consumption, so listening to your body and relying on your pre-tested race-day plan is crucial. If you have pre-existing health conditions, especially those related to blood pressure, consult a doctor or registered dietitian before using salt tablets.

For more information on hydration and electrolyte needs for endurance sports, the National Institutes of Health provides numerous resources and scientific studies on related topics.

Frequently Asked Questions

Most runners start taking salt tablets after the first hour or 90 minutes of running, and continue on a scheduled basis, depending on their individual needs and the product's instructions.

You should always take salt tablets with a sufficient amount of water. A general guideline for fluid intake exists, but this will vary depending on your sweat rate and the weather.

Many sports drinks and gels contain sodium, and for some runners, this may be enough. However, if you are a heavy sweater or running in very hot conditions, you may need extra supplementation from salt tablets.

Taking too many salt tablets, especially without enough water, can cause bloating, nausea, vomiting, and extreme thirst. In rare cases, it can lead to dangerous hypernatremia.

Signs you may need more salt include excessive sweating, white salt streaks on your clothing, muscle cramps, and extreme thirst that isn't quenched by water.

Chewable tablets like SaltStick Fastchews can offer faster absorption compared to capsules and can be more palatable for some runners. The best choice depends on personal preference and how your body responds.

While most of your salt intake should be during the race, some athletes in extremely hot and humid conditions or with very high sweat rates may benefit from a small amount of salt intake before the start.