Stress is a Survival Mechanism
The physical sensations we feel when stress strikes are rooted in our prehistoric ancestors' drive to survive. You think we have stressful conditions? The early humans faced off with wild, carnivorous animals. To outrun their prey, and avoid becoming prey themselves, these ancestors developed a set of physical adaptations to focus all possible energy on survival. Stress hormones temporarily boost our strength, speed and alertness—the qualities that could help us outrun a saber-tooth tiger. Energy is sapped from our digestive, reproductive and other systems that are not necessary for immediate survival. We have a surplus of glucose for energy. It's all focused on preparing us to run or take on our opponent in battle, the reaction we still call “flight or fight.”
Modern Stress is Different
These days, there are no saber-toothed tigers. We have turned other stressors into our virtual saber-toothed tigers, however. Environmental factors and social or psychological challenges are standing in as the main stressors in the modern world. But our bodies have not adapted to the new reality. Physiologically speaking, we react to an angry boss with the same physical sensations that our species developed to react to life-or-death challenges. Our bodies are flooded with stress hormones, such as cortisol and norepinephrine. Our digestive and reproductive systems are squelched in favor of dramatic increases in blood pressure and heart rate. But we don't use this reaction to run away for several miles at top speed. The body's systems go into what was once a rare and necessary state of survival in response to sometimes slight psychosocial challenges in the modern world.
We Need Some Stress
Sometimes, our stress response proves to be a positive thing. When it kicks in as we realize we are beginning to cross the street amid oncoming traffic, we suddenly have the improved reaction time and drive to jump back to the curb. Also, mild stress such as having a deadline to meet or a child's cries to answer keep us engaged and productive in our lives. We also learn to manage stress by dealing with it. So long as the stressors in our life do not overwhelm the system, we can learn to recognize our stress response and bounce back more efficiently over time.