I'm late to the party but FWIW, I always feel this way when I use a treadmill.  I don't do it often at all, but when I do, yeah, light headed.  It's

interesting, using a treadmill on a cruise ship!

 Funny feeling... I felt like when I walk off a boat... a bit dizzy kinda. I felt like that after my fall too and thought it was weird that a fall would make me dizzy.