All of us experience stress, to one degree or another, in our everyday lives.
Stress is the body's reaction to an event that is experienced as disturbing or threatening.
Our primitive ancestors experienced stress when they had to fight off wild animals and other threats. In the contemporary world we are more likely to experience stress when we face overwhelming responsibilities at work or home, experience loneliness, or fear losing things which are important to us, such as our jobs or friends. To prepare for fighting or fleeing, the body increases its heart rate and blood pressure. This sends more blood to our heart and muscles, and our respiration rate increases. We become vigilant and tense.