I don't have experience taking pre-med classes but my accounting courses were very demanding. I would suggest starting small and building up. Find out what activity outside of class is a priority for you and start from there. If sports are important, there are usually less demanding teams (intramurals) you can sign up for! You will find clubs and other groups differ between how much time they demand, so I would make sure to ask those involved already how they time manage. Each year of college I added one more outside of class activity to my plate until I felt I was at capacity. Recognizing when you cannot take on anything more is a great life and work skill (it's awesome you are already thinking about this!).
It's a good idea to get involved in extracurriculars or sports because you cannot study 100% of the time. You need these kind of activities to de-stress, re-charge, have fun, and learn outside of the classroom! In addition to your well-being, these sort of activities show medical schools that you are a well-rounded individual who can balance their work and personal life. I would also suggest you could look into EMT opportunities while in school, as I know pre-med students who did this on the weekends!
I definitely agree with Meghan about finding time for extracurriculars for destressing. I know that medical schools are interested in students with multiple interests they are truly passionate about. Through my personal experience in undergrad, I was a member of a couple different extracurricular clubs and still found some time for intramurals here and there. It truly comes down to finding a good rhythm of time management, which will only help you in the long run in medical school (trust me, it's very very important!).
At the same time, I would make sure to test out extracurricular activities that you are invested in and could possibly see yourself holding an executive board role in going forward. From my discussions with other students and advisors, the biggest takeaway about extracurriculars that a medical school admission person looks at is whether you enjoyed it versus whether it was a resume filler. Find a couple activities that you really enjoy and stick with those if possible!
Bottom line, TLDR: it is 100% possible to allocate time to these activities and do well in your studies, and I know you can do it. It comes down to allocating time to each, and reaching out to tutors/friends/active listeners when you need it. Don't hesitate to reach out to me if you have any other questions!
While I didn't study Pre Med in college I did participate in extracurricular activities. I spent four years as a student manager for the men's basketball team while in school. This required a lot of time. However, it was incredibly beneficial for a variety of reasons. First, it helps you develop time management skills. Second, it allowed me to get a jump start on a career path I was interested in following. Third, the connections and friendships made are invaluable. I made lifelong friends and was able to network and leverage recommendations when it came time to pursue career opportunities closer to graduating. Maybe you can find activities that tie into your course work? Either way, you can absolutely get involved and I believe it's incredibly beneficial. Best of luck!