Hydration and electrolyte balance are key to optimal performance, and salt, particularly sodium, plays an essential role. While many people rely on plain water, evidence shows that sodium-rich solutions provide distinct benefits in maintaining blood volume, preventing muscle cramps, and even enhancing endurance and speed. Here’s why and how adding sodium to your hydration strategy can make a difference.
The Drawback of Plain Water Alone
Did you know that drinking only plain water might actually hinder your performance?
This effect varies depending on the intensity of your workout. For high-intensity exercise especially, consuming water without added sodium can lead to increased diuresis and a reduction in plasma volume, both of which can negatively impact performance. In fact, plain water can lower power output in high-intensity situations by pooling in the stomach, causing bloating and discomfort, which ultimately affects your ability to perform at your best.
Research has shown that during high-intensity cycling, plain water can reduce performance by around 2.5%.
However, in moderate or longer-duration exercise, water may be beneficial, but it’s important to time it well and avoid drinking too much too quickly. Adding sodium to your fluid intake before and during exercise can make a notable difference.
Why does plain water negatively affect performance at higher intensity and not at lower intensity?
One reason is that exercising at or above 70-75% VO2 peak (Zone 3) compromises gastric emptying, whereby fluids can accumulate in the stomach, leading to abdominal bloating, gastrointestinal discomfort, and reduced performance. If you consume plain water at a rate greater than gastric emptying, this can reduce performance.
The solution? During high-intensity performance (Zone 3 or higher), the data suggests that it’s better to consume < 150ml of water every 15 minutes, otherwise you could impair performance.
Why Salt Works
So why does drinking salt solutions prior to vigorous exercise improve performance?
One key reason is that after only 10-15 minutes of cycling at around 70% of peak VO₂, plasma volume can drop by 8-10%. Consuming a high-sodium solution before exercise helps maintain blood volume during physical activity. This support aids in delivering oxygen more effectively to the muscles and heart while also enhancing the removal of waste products.
Sodium solutions improve performance not only by keeping blood volume stable but also by enhancing your body's ability to absorb fluids efficiently.
"Consuming high-sodium solutions prior to exercise has shown consistent benefits for improving exercise performance at both normal ambient temperatures and in the heat."
Sodium helps the body retain water and maintain fluid balance. Research suggests that a minimum of 1,886 mg of sodium (4.7g of SALT) per litre of fluid is needed to increase blood volume effectively. This concentration would be reserved for race day or when exercising in the heat to help avoid dehydration and keep your body’s circulatory function in top form during exercise.
Benefits of Adding Glycine
Adding glycine to a sodium solution further boosts its effectiveness. Glycine helps the body by:
helping it absorb water and sodium faster
stabilising blood volume
lowering core body temperature.
For exercise sessions under an hour, I would prioritize glycine over glucose. Glycine can support energy demands similarly and works optimally when combined with glucose for shorter exercise durations. Adding 5g of glycine to a high-salt drink can potentially extend the peak blood volume expansion effect, sustaining it for up to 4 hours. This combination not only aids in hydration but also helps maintain performance through a longer-lasting blood volume boost.
Beyond enhancing hydration, glycine supports muscle function and may even prevent cramps and promote ligament strength, making it an excellent addition to any hydration strategy.
Sodium Needs for Different Conditions
The right amount of sodium in your hydration strategy depends on factors like exercise duration, intensity, and ambient temperature. Here’s a quick breakdown of what you might need:
To prepare a pre-workout salt solution, consider the following formulations:
For Temperatures Below 26°C (Ambient Temperature):
Moderately high-salt solution (984-2,017 mg of sodium or 2.46g to 5g of salt) in 768mls of water.
Add 4-6 grams of glycine.
For Warmer Weather and Moderate Intensity:
Consume 2,300 mg of sodium (equivalent to 5.75g of salt) per litre of fluid.
Add 4 grams of glycine for every hour of exercise.
For Everyday Runs:
Consume a minimum of 680 mg (equivalent to 1.7g of salt) of sodium per litre.
Add 4 grams of glycine to the water.
These guidelines help prevent low blood sodium levels, which is common during endurance events as the body tries to conserve water but lacks the salt necessary to retain it properly.
The Power of Sodium for Endurance and Recovery
Ingesting the right amount of sodium can lead to:
Reduced thirst and fatigue: Keeping hydrated means you’re less likely to feel overly thirsty or exhausted during exercise.
Enhanced blood volume and circulation: Sodium solutions boost blood volume, keeping oxygen and nutrients flowing to your muscles.
Better speed and endurance: Sodium helps stabilise energy and endurance levels, allowing you to perform longer without fatigue.
Lower core body temperature: Keeping cool is essential, especially in hot environments, and sodium combined with glycine has been shown to reduce body temperature.
Fewer cramps: Sodium is key in preventing muscle cramps, which can sideline even the most seasoned athletes.
How to Rehydrate
For training, full pre-hydration with salt, water, and glycine is generally unnecessary unless you’re feeling fatigued or dehydrated; in that case, it can boost energy and improve performance.
Otherwise, simply drinking when thirsty during training may be enough, as this allows mild dehydration (about 1.5–2.5% drop in body weight), which can encourage beneficial adaptations. After training, rehydrate by consuming a solution with a sodium level similar to your sweat loss to replace fluids and electrolytes without overloading. To track this, weigh yourself before and after training to measure how much fluid to replenish.
The most effective rehydration strategy is to drink a solution with a sodium concentration similar to that of your sweat. On average, people’s sweat contains about 1,200 mg of sodium per litre. Each sachet of Naru Revive provides 1,000 mg of sodium, making it a practical choice for replenishing sodium levels post-exercise to support optimal recovery and hydration.
A Smart Approach to Hydration
Being just 2% dehydrated has can impair coordination and cognitive tasks. However, the feeling of thirst usually doesn’t occur until you’ve already lost ~ 2-3% of your body’s total water.
To stay optimally hydrated without overloading on fluids, start by showing up hydrated and monitor your fluid loss post-exercise. Replenish with a salt solution that matches your sweat loss, replacing both the fluid and sodium you’ve expended. Remember, the goal is not to over hydrate but to maintain balance.
Sodium absorption is also impaired during exercise, which is why it is best to ingest sodium and fluid prior to exercise.
Preventing Mineral Losses
Sodium is also crucial for conserving other minerals, including magnesium and calcium, which are vital for muscle and bone health. If you’re on a low-sodium diet or exercising intensely, sodium losses can lead to an imbalance, pulling magnesium and calcium from your body’s reserves and leading to fatigue or cramping. Maintaining a good sodium balance is essential for overall mineral retention, especially if you’re exercising regularly, intermittent fasting or on a keto diet.
Summary
Sodium intake before, during, and after exercise isn’t just a hydration tip; it’s a performance strategy. By consuming sodium solutions, you’ll experience improved endurance, less fatigue, and faster recovery. Whether you’re an endurance athlete or just looking to improve your performance, a salt-focused hydration plan will give you the edge you need to stay strong, focused, and ready for the next challenge.
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