You're legit about to pass out
No one wants you to pass out or vomit all over your spin bike. For lots of reasons. (Can you imagine the smell of vomit mixed with sweat in a poorly ventilated cycling studio? Woah.)
If you're feeling shaky, nauseated, dehydrated, or lightheaded, stop what you're doing and take a water break. If that doesn't help, leave class and walk around slowly or sit down to try to recover. Nikki Ferguson, a teacher from Tennessee, admits she's had to leave class a couple times during hot and intense workouts, "Once was a spinning class in college. The other time was in a really hot yoga class. I ended up going back in, but I needed to cool off."
Trust me, everyone will understand. Just signal to your instructor that you need water as you leave the room.
Your instructor is abusive in any way
Sadly, some fitness instructors are giant jackasses. You should never feel awkward or guilty about telling someone their behavior is unacceptable by leaving the room.
For instance, Kris Olsen, a business owner and avid runner from Ohio, admits she wishes she would have left a class where the trainer felt it necessary to comment on her ass as she was taking a break. He said, "If you don't want that ass, you better get off that ass and back to training." She finished the workout, but never went back.
Angela VanBrackle, a community development manager for the National MS Society, had a similar experience, "I went to a beginner yoga class, and the instructor was yelling at people for not taking the sanctity of yoga seriously; for not trying hard enough to master the poses. Then, she put the class on hold to yell at someone quietly stretching in the back of the room. It was the most awkward and un-zen yoga class I've ever experienced."
Fitness instructors use many tactics to elicit a response from their clients, but that doesn't give them the right to embarrass or bully someone in front of a class. If it happens, leave, and if you can, file a formal complaint about the instructor to their superiors.
Your classmates are total jerks
I'm not talking about the kind of people who are a little bit cliquey with their workout friends and simply don't go out of their way to include you. I'm talking about the types who harness their inner Mean Girls and make a point of harassing or ignoring you to the point of obvious shunning.
Lillian M., a self-proclaimed "faceless bureaucrat" for the US government, shares one such experience, "I got there before class started, so I sat on my mat, while the other people (who all knew each other) socialized amongst themselves and gave me major side-eye. I tried striking up a conversation, but no one was interested in talking to the new girl. It was capped off by the instructor looking at me like I had just walked out of a UFO and saying, 'Oh, you're new,' before turning around and not speaking to me again."
Exercise is supposed to be fun, or at least not awful, especially if you're shelling out big bucks to participate. While I'd suggest trying to stick it out if you can, don't feel bad about leaving if the experience feels toxic, and don't hesitate to ask for a refund.