answer:Endorphins: “Many studies show that people who exercise regularly benefit with a positive boost in mood and lower rates of depression. Improved self-esteem is a key psychological benefit of regular physical activity. When you exercise, your body releases chemicals called endorphins. These endorphins interact with the receptors in your brain that reduce your perception of pain. Endorphins also trigger a positive feeling in the body, similar to that of morphine. For example, the feeling that follows a run or workout is often described as ‘euphoric’. That feeling, known as a ‘runner’s high’, can be accompanied by a positive and energizing outlook on life. Endorphins act as analgesics, which means they diminish the perception of pain. They also act as sedatives.”