Human physiology is the study of how the human body functions. It encompasses molecular, cellular, endocrine, cardiovascular, respiratory, and other physiological systems. Applied human physiology includes areas like space physiology, sports physiology, exercise physiology, and clinical physiology. The field is becoming more holistic as it appreciates interactions within the body and between the body and its internal and external environments, both currently and historically. In the future, human physiology may integrate human consciousness, psychology, ancient wisdom traditions, and insights from enlightened individuals to better understand subtle interrelationships between humans and nature.