Give examples of heart rate increasing hormone.

The sympathetic components increase heart rate by releasing the neural hormone called the catecholamines. Epinephrine and norepinephrine are the catecholamines which increase heart rate. They are referred to as a 'fight or flight' hormones, as they help the body to cope up with stress. They normally produce effects such as increased heart rate, increased blood pressure, widening of pupils, widening of air passages in the lungs and narrowing of blood vessels in non-essential organs. This enables the body to perform well in stressful situations.