Euan Ashley, MB ChB, DPhil, chair of the department of medicine and professor of genetics and of biomedical data science, leads the MotrPac project, a research group that analyzes the effects of exercise on humans and animals. Ashley discusses what exercise does to the human body on a molecular level, why that matters, and how to incorporate exercise into daily life, including short bouts of “exercise snacks.” He also shares practical tips on how best to gain the benefits of exercise and how it can stave off disease.