In medical and biological terms, stress refers to any physical, mental, or emotional factor that induces tension in the body or mind. Stressors can be external, such as those arising from environmental, psychological, or social situations, or internal, like illness or medical procedures. Stress can trigger the "fight or flight" response, a complex interaction of neurological and endocrine systems. Hormones like adrenaline and noradrenaline promote immediate physical reactions to prepare the body for intense activity. These reactions include increased heart and lung activity, changes in skin color (either paling or flushing), slowed or halted digestion due to stomach and intestinal inhibition, effects on body sphincters, blood vessel constriction in various areas, release of nutrients like fat and glucose for muscle use, dilation of blood vessels in muscles, and suppression of tear and saliva production. Other effects include pupil dilation, muscle relaxation, inhibition of erection, reduced hearing, narrowed vision, disinhibition of spinal reflexes, and trembling. Stress can exacerbate or influence numerous medical issues, including psychological disorders such as depression and anxiety. It can also impact physical health, leading to poor wound healing, various medical complications, and inadequate control of certain conditions. Effective stress management, which includes both pharmacological and non-pharmacological strategies, is recognized as a beneficial approach to treatment.