Stress could have different reactions on everyone. Some people tend to have an increased appetite or have an upset stomach. All of these reactions to stress are normal and valid since the endocrine system is a major factor that controls the way we react.
Personally, when I get stressed, I tend to have an increased blood pressure and heart rate, insomnia, and being too focused on the topic. After studying the Endocrine system, I now have an idea on how these manifestations occur.
When we are stressed, the hypothalamus sends a message to the pituitary gland to encourage the adrenal glands to produce cortisol (APA, 2018). The adrenal glands secrete a number of hormones when we are in physical and emotional stress. One example of this is the cortisol hormone. This hormone helps our bodies by boosting our energy levels and becoming more aware in stressful situations, which explains why I become more focused when I am stressed. On the other hand, adrenaline (epinephrine and norepinephrine) are capable of increasing our heart rates and control our blood pressure when we are stressed, thus being the reason why these manifestations happen to me.