It is wise to choose science related classes while you're in school, such as biology, psychology, chemistry, anatomy and human development. You should also look to obtain a bachelor's degree in science or a health related field. You can be hired as a health teacher even if you don't have a degree in the health field. Many schools are looking to bring aboard teachers that have at least a bachelor's degree, which can be acquired in four years in most cases.
After getting your license degree, you will have to acquire teaching degree. All states have different requirements for becoming a teacher, but all states you must take a teachers test. This health teaching test covers the grounds of math, reading, science and additional subjects.
After obtaining a bachelor's degree, you may find that passing the certificate exam to be quite simple. It is a good idea to try to form a study group, find a study partner or a study guide, which can be found in book stores that offer exams. The exam you'll take is different in each state, but they all expect the teachers that take the exam to have the same knowledge of science, reading, history, reading and math.
It's important to keep up to date with health field related topics. One great source to use to find different health threats and conditions is to use the CDC as a resource.