Which hormone leads to increased heart rate and elevated blood pressure during stress?

Epinephrine, commonly known as adrenaline, plays a crucial role in the body's "fight or flight" response to stress. When an individual experiences stress, whether physical or psychological, the adrenal glands release epinephrine into the bloodstream. This hormone directly impacts several physiological processes to prepare the body for immediate action.

One of the primary effects of epinephrine is its ability to increase heart rate, which enhances blood flow to muscles and vital organs, enabling a quick response to the stressful situation. Alongside this, epinephrine causes the blood vessels to constrict in certain areas while dilating them in others, which leads to an overall increase in blood pressure. This combined effect ensures that the body is primed for high levels of physical performance, making it essential for survival in high-stress scenarios.

The other hormones mentioned do not have the same primary role in stress response. Insulin primarily regulates blood glucose levels, glucagon helps raise blood sugar during fasting states, and calcitonin is involved in regulating calcium levels in the body. Thus, epinephrine stands out as the hormone specifically associated with increasing heart rate and blood pressure during stress.