Early signs of heart disease and stroke can be detected. Teens who smoke have less endurance and lower performance in physical activities. The resting heart rate of a teen-age smoker is two to three beats faster than a nonsmoker's. Smoking at an early age increases the risk of lung cancer. Teen-age smokers suffer from shortness of breath almost three times as often as teens who don't smoke.
Nicotine can be as addictive as illegal drugs, including cocaine.
Among addictive behaviors, smoking is the one most likely to take hold during adolescence.