Stress (definition of)

Although stress is a highly subjective thing that means different things to different people, it can be generally defined as a physical, chemical or emotional response to perceived threats. It is also known as the "fight or flight" response. Those events which trigger such a response are known as "stressors," and are different for every individual. Stressors range from deadlines at work or public speaking to being diagnosed with mesothelioma, sometimes referred to as asbestos cancer.

Where it Comes From

From an evolutionary standpoint, stress was that which saved the caveman's life when he encountered a saber-toothed tiger or pack of hungry wolves. It increased his strength and awareness. Today, some forms of stress can sometimes be helpful and encouraging when it comes to real survival.

The problem is that back in the day, a caveman might encounter a real life-threatening situation two or three times in his lifetime (which arguably, was about forty years at best). The problem is that today, humans - whose brains have not changed appreciably in 100,000 years - encounter saber-toothed tigers several times a day in the form of work situations, economic issues, terrorist alerts, rush-hour traffic, and more. Over time, such stress can take a heavy toll on the body - and severely weaken the immune system.

The Cost and Mechanism

Stress is known to cause depression, heart attacks, stress and high blood pressure. Those who have experienced truly life-threatening situations events such as war, sexual or physical assaults, or natural disasters are also vulnerable to post-traumatic stress disorder - first identified during the First World War and defined as "shell shock."

When stressors are encountered, the body responds by activating what is known as the "stress response." The brain's hypothalamus gland signals the body's adrenal glands to increase adrenaline production and produce extra cortisol hormones, releasing these them into the bloodstream. This in turn increases the body's metabolic rate, speeding up breathing and heart rates and raising the blood pressure; blood vessels to expand in order to feed glucose to the muscles; the pupils dilate for improved vision, and excess sweat is produced for cooling. It is similar to flipping on a supercharger on an automotive engine.

This reaction was intended for those rare occasions; once the threat has passed, the body returns to normal. However, today, threats are perceived on an almost constant basis. Over time, the results include chronic hypertension and even mental problems as excess adrenaline begins to eat up brain cells.