It’s well-known that regular exercise reduces anxiety and improves mood. Vast amounts of evidence conclude that routine physical activity positively impacts mental health for people of all ages. For teenagers, though, frequent exercise may be a matter of life or death: Ongoing research by professor Jeremy Sibold shows a link between frequent physical activity and a reduction in suicidality by bullied adolescents, who are also at increased risk for low self-esteem, anxiety, depression, sadness and substance abuse.