Suicide is one of the leading causes of death among teenagers in the U.S., ranking only behind accidental death and homicide. While any teenager can develop suicidal tendencies, certain individuals have higher risks than others. Current evidence indicates that regular participation in exercise or organized sports can significantly reduce an adolescent\u2019s chances of thinking about suicide or attempting suicide. According to a new study published in 2013 in the journal Psychological Medicine, the suicide prevention benefits of adolescent exercise don\u2019t end when a teenager reaches adulthood. In fact, they can last for a lifetime. Background Information Suicide accounts for about 11 percent of all deaths among American teenagers, the Centers for Disease Control and Prevention report. This percentage ranks far behind accidental death (48 percent), but only slightly behind homicide (13 percent). The most common modes of teen suicide are self-inflicted gunshot, self-suffocation and self-poisoning. Nine out of 10 teens who attempt to kill themselves have symptoms of depression or some other identifiable mental health issue, according to the American Academy of Pediatrics. Other common risk factors include a history of suicide within one\u2019s family, exposure to traumatic life events, a history of significant personal loss, a history of legal problems that result in arrest, convenient access to guns or other suicide options, and a prior history of suicidal behavior. While teenage girls attempt suicide more often than teenage boys, boys account for four out of five teen suicide-related deaths. Exercise as Short-Term Prevention In a study published in 2007 in the journal Medicine and Science in Sports and Exercise, a team of researchers examined the effects of regular exercise and\/or participation in organized sports on suicidal thinking in teenagers, as well as on actual suicide attempts. After analyzing a survey that included more than 10,000 high school-age teens, the authors of the study concluded that, when compared to high school boys who don\u2019t exercise, boys who exercise \u201cvigorously\u201d or play a team sport contemplate suicide substantially less often; boys who exercise or play a team sport also make actual suicide attempts substantially less often. The same findings held true when the study\u2019s authors compared the rates of suicidal thinking and suicide attempts among non-exercising teenage girls to the rates found among teen girls who exercise vigorously or participate in a team sport. The authors of the study did not determine why exercise reduces suicide-related risks among teenagers. However, they did list several possible explanations. For example, participation in regular exercise is known for its ability to improve mental health and the stability of any given individual\u2019s conscious thought processes. Since mental health issues play such a prominent role as a teen suicide risk, exercise may produce its beneficial effects by directly reducing this risk. In addition, the suicide prevention-related benefits of sports participation, in particular, may also stem indirectly from involvement in the supportive social networks that commonly develop among teammates and coaches. Exercise as Long-Term Prevention In the study published in Psychological Medicine, a team of Swedish researchers examined the life histories of more than 1 million adult Swedish men. In particular, the researchers looked at the level of physical fitness these men achieved by age 18, then compared that level to the men\u2019s rates of suicide over the following decades. This comparison was possible because, up until 2010, all Swedish men had to go through mandatory physical testing at age 18 prior to compulsory service in the military. In a 2012 study using the same group of participants, the authors of the 2013 study had already demonstrated that men who were in good physical condition at age 18 had much lower rates for severe depression in later years than men who were in poor physical condition at their 18th birthdays. The new study furthers this work by demonstrating that good physical health during late adolescence leads to an almost 50 percent drop in suicide-related risks during adulthood. This benefit still remained in effect four decades later as the study participants approached their 60s. The authors of the study offered a couple of potential explanations for the long-term benefits of exercise in suicide prevention. First, teenage depression is a strong predictor of later suicide attempts, and exercise\u2019s beneficial effects on depression symptoms likely continue to manifest throughout adulthood. In addition, participation in regular exercise may have long-term effects on the brain\u2019s ability to withstand the everyday and extraordinary stresses that inevitably occur during adult life.