Several physical illnesses can prevent students from participating in school sports for extended periods. Common conditions include McArdle's disease, which causes extreme intolerance to exercise due to the body's inability to break down glycogen, leading to a sedentary lifestyle. Kearns-Sayre syndrome is another genetic disorder that affects depth perception and coordination, making physical activities dangerous. Anemia, which impairs oxygen efficiency, and sickle-cell disease, can also limit physical exertion. Additionally, asthma is prevalent in certain regions, such as North Africa, and can significantly impact a student's ability to engage in sports. These conditions highlight the importance of understanding the specific health challenges that may affect students' participation in physical activities.