Health science is that the study of psychological and behavioural processes in health, illness, and health care. it's involved with understanding however psychological, behavioral, and cultural factors contribute to physical health and malady. Psychological factors will have an effect on health directly. for instance, inveterately occurring environmental stressors poignant the hypothalamic–pituitary–adrenal axis, cumulatively, will damage health. behavioural factors may have an effect on a human health. for instance, sure behaviors will, over time, damage (smoking or overwhelming excessive amounts of alcohol) or enhance health (engaging in exercise). Health psychologists take a biopsychosocial approach. In alternative words, health psychologists perceive health to be the merchandise not solely of biological processes (e.g., a virus, tumor, etc.) however conjointly of psychological (e.g., thoughts and beliefs), behavioural (e.g., habits), and social processes.