Being more physically active may help teens become less active smokers, U.S. researchers say. Kimberly Horn of The George Washington University School of Public Health and Health Services said the study involved 233 teenage smokers who reported little physical activity. The study, published in the Journal of Adolescent Health, found teens who were more physically active did better at cutting back or quitting. Horn said intense activity was not really needed to have an impact. \"Increasing the number of days in which they get just 20 minutes of exercise -- which can be as simple as a walk -- may increase a teen\'s chances of quitting smoking,\" Horn said. The greatest benefit went to active teens in an intensive quit-smoking program.