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Decoding Sports Drinks: Unravelling the Hypotonic, Isotonic, and Hypertonic Puzz

Last month, we reported on the science showing that some hypotonic sports drinks can hydrate the body better than water!

We also delved into the different osmolarity categories of sports drinks and what each category is for. Now, we connect the scientific knowledge with practical application. How do we as consumers identify which commercially available sports drinks are hypotonic, isotonic, or hypertonic?

Cracking the Code: Identifying Sports Drink Types

1. Label Reading: The first step in identifying the type of sports drink is to scrutinize the label. Look for key indicators such as the sugar content (grams per serving), electrolyte levels (sodium, potassium, magnesium), and the osmolality. Osmolality measures the concentration of solutes in a liquid, which can help classify the drink as hypotonic, isotonic, or hypertonic.

2. Sugar Content: Hypotonic drinks generally have lower sugar content compared to isotonic and hypertonic ones. Isotonic drinks aim for a balanced combination of electrolytes and carbohydrates, making them suitable for moderate to intense exercise. Hypertonic drinks, on the other hand, tend to have a higher sugar concentration to provide more energy.

3. Electrolyte Balance: Isotonic drinks are formulated to mimic the body's electrolyte balance. Look for sodium, potassium, and magnesium levels on the label. Hypertonic drinks might have higher electrolyte content for energy replenishment.

4. Osmolality: Some sports drinks display their osmolality on the label. A lower osmolality indicates a hypotonic drink, while an osmolality similar to bodily fluids signifies an isotonic drink. Hypertonic drinks have higher osmolality due to their concentrated solute content.

5. Purpose and Use: Consider the circumstances in which the sports drink is recommended. Hypotonic drinks are great for quick rehydration, isotonic for balanced hydration and energy, and hypertonic for sustained energy during recovery.


The Hydration Hierarchy: Hypotonic, Isotonic, and Hypertonic Sports Drinks

We covered the differences in these categories of sports drinks in more detail in a previous article. Here’s a quick review.

Hypotonic: A hypotonic sports drink has a lower concentration of solutes (such as salts and sugars) compared to the body's fluids. This type of drink is rapidly absorbed by the body, making it an excellent choice for quick hydration. It helps maintain fluid balance and is often preferred during moderate exercise or when rapid rehydration is needed. Precision Fuel and Hydration advertises its product as hypotonic.

Isotonic: Isotonic sports drinks have a solute concentration similar to that of the body's fluids. They are designed to replace fluids and electrolytes lost during exercise, making them a popular choice for most athletes engaged in moderate to high-intensity activities. Isotonic drinks provide a balance between quick hydration and energy replenishment. Maximus advertises itself as an isotonic sports drink. Most “sports drink” brands fall into this category or are so slightly hypertonic that they still function more like isotonic drinks. 

Hypertonic: Hypertonic sports drinks contain a higher concentration of solutes than the body's fluids. While they are less effective for rapid rehydration, they can supply a substantial amount of energy. Hypertonic drinks are often used during recovery periods or when sustained energy is required without a pressing need for hydration. Lucozade Energy, made in New Zealand or Australia, is considered to be a hypertonic sports drink.



Choosing the right sports drink can significantly impact your performance and recovery. Understanding the distinctions between hypotonic, isotonic, and hypertonic drinks empowers athletes to tailor their hydration strategy to their unique requirements. By carefully examining labels, analysing sugar and electrolyte content, and considering the intended purpose of the drink, you can confidently select the beverage that best supports your athletic endeavours. Remember, hydration is not one-size-fits-all; it's a nuanced science that can elevate your fitness journey to new heights.

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