Thirty female smokers ( Mean ( M ) age = @ years , Standard Deviation ( SD ) = @ ; M weeks pregnant = @ , SD = @ ; Fagerstrom Test for Cigarette Dependence = @ , SD = @ ; M @ cigarettes/day , SD = @ ; M hours abstained = @ , SD = @ ) were randomized to @ min of mild-to-moderate intensity exercise ( EC ; n = @ ) or passive ( PC ; n = @ ) condition .