Your Brain: The Missing Manual

Stress

In prehistoric times, the fight-or-flight response prepared people for the only actions they had at their disposal. But in the modern world, where we're more often engaged in mental challenges and it's considered bad form to stab someone who corrects your grammar, the fight-or-flight response isn't always appropriate.

Mild levels of arousal can improve attention and performance in school exams, sporting events, and heated debates—because all these actions are short and allow you to respond. Problems occur when you face a stressful situation that lingers on and doesn't provide an obvious avenue for you to act. For example, if you're trapped under the thumb of a sociopathic boss in a dead-end job, but you won't have money to pay next month's rent if you leave, you're in trouble. The constant stress of the situation will continually ramp up your body's fight-or-flight response, while you struggle to continually inhibit your body's natural instincts. After months and years of a situation like this, your body won't be the same.

The Effects of Stress

Constant stress is like having a car alarm going off in your body around the clock. Eventually, you'll learn to tune out the cacophony. However, you'll still end up with a wicked headache at the end of the day.

When your brain feels threatened for long periods of time, your body experiences the following changes:

• High blood pressure. The fight-or-flight hormones that get your body ready to act will also eventually wear it out. The list ...