I was pre-med and majoring in Neuroscience at a preppy liberal arts college, but I was miserable with that. I had always done well in school and I got satisfaction out of being successful, so I assumed I was academically-minded. It turned out I had no real passion for Neuroscience, and I decided being a doctor wasn't the lifestyle I wanted. Too much school, and my life would have been more focused on career than family and hobbies.
For a while I considered Physical Therapy, but finally decided on Nursing because its more flexible. I definitely lean towards health professions. I love the idea of helping in tangible and necessary ways. Plus, there's a lot of job stability.
Seems like a lot of other ISFPs gravitate towards careers that give them an artistic outlet. Either way, I think its a good idea to do something that lets you work with your hands. I don't think I could handle a job that required a lot of abstract theorizing and philosophizing. Give me bed pans and smelly old people!
Good luck