From a hydration point of view, it makes no difference. The dissolved carbon dioxide in sparkling water has no impact on your body's ability to absorb it.
The bubbles themselves might fill up your stomach temporarily and it’s hard to chug a lot of fizzy water at once, but for a given amount of water consumed, you’ll be just as hydrated with or without bubbles.
Fizzy water is slightly acidic, which could theoretically erode your tooth enamel. But the effect is vastly less bad than drinking sugary fizzy drinks or fruit juice.
So, if you choose fizzy water over cola or orange juice, you’ll be improving your dental health.
Other potential effects are more tenuous.
A small study in 2002 found that drinking fizzy water relieved indigestion and constipation better than still water, but the trial only lasted two weeks and involved just 21 people.
Similarly suspect is a 2026 study at the Institute of Health and Sport Sciences, University of Tsukuba, Japan. This was reported as finding that sparkling water helped athletes feel more alert.
Researchers looked at the performance of just 14 young adults playing a football video game and found only fairly mild effects on attention and cognitive performance.
It’s worth noting that the study was partly funded by a soft-drinks company. We also can’t rule out placebo effects either, because the participants knew when they were drinking still or sparkling water.
Ultimately, still and sparkling water are both good for you and the difference between them is orders of magnitude less than between water and alcohol or sugary soft drinks.
Worrying about these subtle differences is like obsessing about the health benefits of romaine versus iceberg lettuce, rather than the difference between salad and macaroni cheese.
This article is an answer to the question (asked by Kerry Roy, Sheffield) 'Should I drink still or sparkling water?'
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