. In order to deliver these substances the pulse rate increase and we breathe faster.
When we are faced with danger (or excitement) we enter a 'Fight or Flight' state, during which adrenaline is released into the blood.
Adrenaline is a hormone that is produced by the adrenal gland and that its effect is to increase heart rate and breathing rate. This gives our muscles the energy we need to either fight or run away.
