I started minoxidil about 6 years ago and went through the same thing and still ocassionally do. I am an avid gym rat and run about 4 miles every other day. I started getting dizzy spells and skipped heart beats a couple years ago (has stopped since) and it really freaked me out. I never really related it to the minoxidil so I just went to my dr. for peace of mind. You should probably do the same. It is better to be safe than sorry.