The human body responds to stress by stimulating the nervous system and secreting various hormones. Secretion of adrenaline and noradrenaline, cortisol, endorphins, growth hormone, prolactin, and testosterone can vary during stress. The brain area called the hypothalamus stimulates the adrenal glands and releases adrenaline and cortisol hormones into the blood. These hormones increase heart rate, respiratory rate, blood pressure, and metabolism. The blood flow increases, and the muscles get more blood, making the body ready for action.