Why am I still thirsty after drinking carbonated water?

November 22, 2025 •

4 min read

According to a 2016 study published in PLOS ONE, the oral sensations of coldness and carbonation can increase the perception of thirst-quenching, making you feel full and satisfied faster. This is a key reason why you may still be thirsty after drinking carbonated water, despite its hydrating properties.

Quick Summary

Carbonated water is just as hydrating as regular water, but its bubbles and cool temperature can trick the brain into thinking you've consumed more fluid than you have, leading to incomplete hydration. Other factors include added ingredients, bloating, and slowed absorption.

Key Points

Sensory Illusion: The bubbles and coolness of carbonated water create a strong sensation of refreshment that can trick your brain into thinking you are fully hydrated faster than you actually are.
Feeling of Fullness: Carbonation can cause bloating, leading to a feeling of fullness that may cause you to drink less liquid than your body needs to properly hydrate.
Hidden Dehydrators: Sugary and caffeinated carbonated drinks actively pull water from your body's cells to balance glucose levels, increasing thirst.
Absorption Rate: While not significantly different for most, carbonated water may be absorbed slightly slower than still water, which can be a factor during rapid rehydration needs.
Hydration Strategy: To combat persistent thirst, alternate between still and unsweetened sparkling water and choose plain varieties without added sugars or artificial ingredients.
Still vs. Sparkling: Plain sparkling water is just as hydrating as plain still water; the key difference lies in the sensory cues that influence how much you drink.

The Sensory Illusion of Carbonation

While plain carbonated water is fundamentally just water with dissolved carbon dioxide, the unique sensation it provides can lead to a physiological miscommunication. The "bite" of carbonation, combined with a cold temperature, creates a sensory perception in the mouth that scientists have found is interpreted by the brain as significant thirst-quenching. This perception can be so strong that it leads you to stop drinking sooner than your body has truly been rehydrated.

This is not a matter of the water itself being less hydrating. Research has consistently shown that sparkling water is as hydrating as still water. The problem lies in the sensory cues. Your brain receives a strong signal of satisfaction, which overrides the underlying physiological need for more fluid. This is particularly relevant for individuals who rely heavily on carbonated beverages to meet their daily water intake.

The Role of Bloating and Gastric Emptying

Another factor is the gas created by carbonation. The carbon dioxide in sparkling water can cause some people to feel bloated or full. This sensation of a full stomach sends another signal to the brain, further reinforcing the message that you have had enough to drink. As a result, you might stop drinking even if your body still requires more fluid to reach optimal hydration. For some, the slight acidity from the carbonic acid can also contribute to this feeling of satiety.

Some studies also suggest that carbonated water may take slightly longer to empty from the stomach compared to still water, though this effect is generally considered minor. For most people, this difference is negligible, but combined with the sensory illusion of fullness, it can contribute to the feeling of still being thirsty later on.

The Dehydrating Effects of Added Ingredients

Not all carbonated drinks are created equal. The most significant reason for persistent thirst is when the beverage contains dehydrating ingredients. Many popular sodas and flavored sparkling waters include the following:

Sugar: High sugar content causes the body to pull water from its cells into the bloodstream to help dilute the glucose, a process known as osmosis. This depletes the cells of water and triggers a thirst response, making you feel thirstier than before.
Sodium: Some brands of mineral-rich or club sodas can contain high levels of sodium. Excess sodium intake increases the body's need for water to maintain a balanced electrolyte concentration.
Caffeine: Many soft drinks and energy drinks are caffeinated. Caffeine is a mild diuretic, meaning it can increase urine production and potentially contribute to fluid loss.

It is crucial to read the ingredients list. A flavored sparkling water with no sugar, artificial sweeteners, or caffeine will be just as hydrating as regular water. The problem only arises when these additional dehydrating agents are present.

Carbonated vs. Still Water: A Comparison Table


Feature	Plain Carbonated Water	Plain Still Water
Hydration Efficacy	Equal to still water	The gold standard for hydration
Thirst Perception	Can create a sensory illusion of quenched thirst due to carbonation and temperature, potentially leading to less overall intake.	Relies purely on physiological signals, ensuring adequate intake to resolve thirst.
Feeling of Fullness	Bubbles can cause bloating and a sensation of fullness, causing you to drink less.	Does not induce bloating from gas, allowing for unimpeded intake.
Gastric Emptying	May be slightly slower than still water, though the effect is small.	Absorbed more quickly, making it ideal for rapid rehydration, like during exercise.
Electrolytes	Mineral content can vary by brand; some have added sodium.	Generally low or no mineral content, though some brands offer added electrolytes.
Flavoring	Many flavored options exist, some with dehydrating sugars or artificial sweeteners.	Neutral taste, best for sensitive stomachs and pure hydration.

How to Overcome Persistent Thirst

If you find yourself repeatedly feeling thirsty after drinking sparkling water, consider a few adjustments to your hydration strategy. For those who enjoy the fizz, alternating between plain still water and unsweetened sparkling water can help ensure you don't fall victim to the sensory illusion of being fully quenched. It's also important to pay attention to your body's true thirst signals and not just the initial mouthfeel.

Here are some practical steps:

Balance your intake: Have a glass of plain still water for every glass of sparkling water you drink. This ensures you are hydrating based on your body's needs, not just on sensory cues.
Watch the ingredients: Choose plain, unflavored sparkling water or brands that explicitly state they have no added sugar, sodium, or artificial ingredients.
Limit consumption during exercise: Avoid carbonated water during intense workouts. The bloating and gas can cause discomfort and hinder proper rehydration when you need it most.
Add your own flavor: Infuse plain sparkling water with natural fruits like lemon, cucumber, or berries to get the flavor without the dehydrating effects of sugar.
Reconsider other beverages: Be mindful of other drinks like coffee, tea, and alcohol, which can also have diuretic effects and contribute to overall dehydration.

Conclusion

The perception of being quenched after drinking carbonated water can be a sensory illusion, leading you to consume less liquid than your body actually needs. While carbonated water itself is not dehydrating, the combination of oral sensations, feelings of fullness, and potentially dehydrating additives in sweetened versions explains why you might still feel thirsty. By understanding these factors and adjusting your hydration habits, you can enjoy the satisfying fizz of sparkling water without compromising your body's true need for fluids. Prioritizing plain still water, especially during physical activity, remains the most straightforward way to ensure optimal hydration throughout the day.

For more information on the sensory aspects of hydration, you can visit the Monell Chemical Senses Center website.

Frequently Asked Questions

No, scientific studies have shown that plain sparkling water hydrates the body just as effectively as still water, because the base ingredient is the same.

The dissolved carbon dioxide gas in sparkling water creates bubbles that can cause bloating and a feeling of fullness, which signals to your brain that you've consumed a sufficient amount of liquid.

If the flavored sparkling water contains added sugars, artificial sweeteners, or caffeine, it can increase your thirst. High sugar content, in particular, can cause your body to pull water from your cells to dilute glucose in the bloodstream, triggering a thirst response.

Plain, still water is best for rapid rehydration, especially during or after exercise, as it is absorbed by the body most quickly without causing bloating from carbonation.

For some individuals, especially those with sensitive stomachs or conditions like IBS, the carbonation can cause bloating, gas, and discomfort. For most people, however, it is generally not an issue.

When you consume sugar, it enters your bloodstream and draws water out of your body's cells to help dilute it. This cellular dehydration is what causes you to feel an increased sense of thirst.

The combination of the cold temperature and the biting sensation of carbonation stimulates oral receptors that signal a strong feeling of refreshment and satiety to the brain, even if you haven't consumed enough water.