Health psychology is the defined as studying of psychological and behavioral processes in health, illness, and healthcare. It contributes to is concerned with the understanding of how psychological, behavioral, and cultural factors contribute role to in physical health and illness. Psychological factors can affect health directly. For example, health is hurt by the chronically occurring environmental stressors which cumulatively affecting the hypothalamic–pituitary–adrenal axis, cumulatively, can harm health. On the other hand, a person's health is also interwoven with the Behavioral behavioral factors can also affect a person's health. For exampleinstance, certain behaviors behaviors, including smoking and excessive alcohol consumption can, over time, harm (smoking, excessive alcohol consumption) health but exercise and diet low in saturated fat or can enhance health (exercise, diet low in saturated fat).