A physiologist is a medical science specialist who performs research to see how the body functions at a cellular level in different conditions. An exercise physiologist, for example, studies how the body reacts to various forms of exercise and physical stress. In this career, you may research people running on treadmills or swimming underwater. You may study the cellular-level effects of nutrition on the body or focus on extreme conditions by researching organisms in space or at high altitudes. In any field, your job duties include conducting experiments, trials, and other studies, collecting the data, and publishing your research results for the use of the scientific community. Some physiologists specialize in plants and animals instead of humans.