Hi
@Cana ,
Personally, I find myself more insulin sensitive in the heat.
I sing in two rock bands. I normally keep water handy just to "wet the tubes" during a gig. Normally a bottle down by the monitor? Along with a seperate drinkable hypo treatment. (But that's just standard insulin dependant procedure.)
Just like fasting the afternoon prior to a gig I make sure I don't consume massive abouts of fluid in one go, restricting the diaphram & breathing as a vocalist. (But this is just ritual accommodating my personal diabetes regime.)
I'm not sure what the set up is with your Rock choir? But you could keep a bottle handy by your feet..(or if you use a music score sheet stand? Or mic stand. Oddly there are bottle holders on the market that can clip on & accomodate your beverage of choice..
Have a great gig!