Location: Center for Narcolepsy research, Stanford University, 701 B Welch Road Help us better understand breathing regulation Seeking non pregnant, healthy adults ages 18- 40 years, without lung or cardiac disease. Payment of $40 for participation. Participants will perform a breathing test, give a blood sample and complete a questionnaire. Participation will take one hour. Please contact the Research Coordinator at efratb@stanford.edu. Title of Study: Environmental and genetic factors in the ventilatory response to hypoxia and hypercapnea. For general information about participant rights, contact 1-866-680-2906.