You’re not immune to health conditions when you’re travelling. If anything, you’re more susceptible. You’ll be subjected to more illnesses because of the number of people you’re interacting with, after all.
One way to narrow down your options is to consider what type of fitness writing you're most interested in. For example, do you want to write workout routines, share your own personal fitness journey or keep your readers informed.
If there’s one thing that’s going to allow you to have more fun when you’re away, it’s knowing about your surroundings and being aware of what’s going to be happening while you’re there.