I'm not sure what exactly schools are looking for, but I got in to U of Minnesota and Midwestern-Glendale with ~2-3 hours/week of volunteer hours. I think quality of hours is better than quantity, so doing something in a health care setting is probably the best. Most of my hours have come from a mentoring program. I mentor a 6th grader for in school for about an hour every week. We also meet outside of school for different fun group activities (bowling, going to the YMCA, etc.)
I don't think a person has to put in a ton of hours...pick one or two volunteer opportunities you enjoy and you feel like you can make a difference by participating in and I think you should have that aspect of your application covered.
Scholarship Access: Becoming a Student Doctor course
