There are actually significant changes that take place in the body when we face a threat such as increased heart rate and blood pressure, and the secretion of certain hormones.

When we remain in a state of stress for long, we expose our bodies to the stress responses for a prolonged time and 
this can be extremely dangerous in the long run. Here are some adverse effects of regular exposure to stress:

1. Increase in blood sugar
2. Rapid breathing
3. Weakening of immune system
4. Muscle stiffness
5. Increase heart rate and blood pressure
6. Digestive problems
7. Anxiety and panic attacks