I know some painters who spray new basements all the time without a paint suit, etc. However the entire floor is usually white with overspray. they use a fan and it may help move the overspray around. If you are not worried about overspray, then have at it.
Otherwise as jb said, rolling may be easier and not as messy. It goes fast once you get started. Otherwise I'll let the ones who like to paint and paint regularly post up with their 2 cents.