Girls, how do you avoid washing your hair every day if you workout everyday?

I run on my treadmill every day. & I'm usually fine wish washing my hair right after, because it's really long (right down to the small of my back) & gets REALLY gross when I sweat! However, lately my hair & scalp have been really taking a toll due to all of the washing (since it's bad to wash your hair everyday.) So, what do you do? Do you wash it after? Do you use a dry shampoo? If so, please suggest a good brand? :)