LCHF, T1 & joining the gym

Take plenty of glucose would be my tip! I used to do about an hour in the gym and found I needed to test regularly (I did it in between machines) and top up with glucose tablets as necessary.

For classes, I always test right before ot starts, then at regular intervals. I put my glucose tablets and meter ready at the side so I can nip back to them easily. I also swim and do the same for that. Beforehand I reduce my bolus if eating a meal within a couple of hours of exercise.

Bear in mind that some people find exercise raises their sugars though, so be led by your own body.

Exactly what @azure has advised. I also find if I know my workout is one that is likely to drop my blood sugar ( this only comes with experience) , then I mix orange cordial , water , and 2 spoons of glucose powder ( available from Holland and Barrett).
I make up about 750 ml and find drinking little and often throughout my workout keeps me fairly level.
Always remember when exercising to hydrate before you feel thirsty, if you start to drink when you're really thirsty it's a little bit to late.
Have fun. That's what exercise is all about.

I walk for an hour each day to manage my insulin dose. I have a banana before, and Test after. My DSN said I should Test during walking but I don't TBH. I Test after and if low I have an energy bar or banana depending on reading and reduce my evening meal insulin dose....