High school students should study health, biology, mathematics, chemistry and physics. Accredited training programs for respiratory therapists may either be a 2-year program leading to an associate degree or a 4-year program leading to a bachelor’s degree. Course work focuses on mathematics, human anatomy and physiology, chemistry, physics, microbiology, and career specific classes. Upon completion of a 2-year or 4-year accredited program, graduates must receive a license as a respiratory care practitioner. They may take the exam to become a Certified Respiratory Therapist (CRT). Wisconsin mandates a license to practice, such as a CRT. If a CRT meets education and experience requirements, and passes a separate examination, they are eligible to become a Registered Respiratory Therapist (RRT).