Studies indicate that young people who are involved in athletic activities achieve higher grades and are more likely to complete high school and college. This may be because adequate exercise improves mental acuity. It may also be attributed to the fact that children in sports are less likely to abuse illegal substances, such as drugs and alcohol. Steering clear of these substances helps young people stay focused on their academics and free of dangerous distractions. There is also evidence that young people who play sports are less likely to start smoking.