Hi Pauline,

I can definitely think of a reason why drinking a carbonated drinks before synchro could make it hard to hold your breathe. The carbonation in the drink produces extra gas (the carbon dioxide makes it fizzy), which you ingest. But, it has to escape somewhere! This is why a lot of people burp. Especially if you drink it fast, you are ingesting extra air, causing you to burp even more.

So if you were to drink a carbonated drink before practice, you'd probably find yourself fighting back the natural urge to burp (allowing that extra gas to expel from your body) while trying to hold your breathe - quite the feat!

Hope this helps!