There is a great book called "Why Zebras don't get Ulcers" by Robert Sapolsky, a professor of neurology at Stanford University. The premise is that when the lion comes all the zebra's experience an initial stress response to stimulate them to get out of harm's way. The minute the lion selects and kills its prey, the other zebra's in the herd shut off there stress response and commence to graze. This is a well calibrated stress response.

The problem with many of us is that the stress response turns on, and for whatever reason, doesn't turn off. This is when stress can have serious consequences to our health. Stress can be caused by many things - psychological stresses like the commute to work, relationship issues such as divorce or separation, or less obvious things like chronic inflammation, heavy metals, poor blood sugar control, or food sensitivities. The interesting thing is it's not the stress that kills us; its our bodies maladapted response to the stress.

Dr. Hans Selye, a noted endocrinologist, was one of the first to research the stress response. He wrote seven books and published 1,700 research papers on the subject. Selye found a relationship between resistance to stress and the amount of time exposed to stress. He came up with the term General Adaptation Syndrome or GAS. When you don't have enough GAS in the tank, you become sick and exhausted.

He described three phases of the stress response; alarm, resistance and exhaustion. Each has its own set of characteristics and recovery times. During the alarm phase, the adrenal glands produce more of the hormones cortisol and DHEA and your sympathetic nervous system (your "fight or flight" response) becomes dominant. This is the stressed and wired phase. If stress continues unabated you enter into the second phase of stress, the Resistance Phase. Cortisol now starts to slowly decrease and DHEA starts to decline as well. You may feel anxiety, begin to experience high blood pressure, digestive complaints such as IBS or ulcers and may experience sleep disturbances such as difficulty staying asleep or difficulty waking in the morning. Finally, there is the Exhaustion phase, where cortisol and DHEA levels become very low. You are now in a parasympathetic state because you have literally burned out your ability to produce the hormones needed for the sympathetic response. This phase is marked by chronic low blood pressure, exhaustion, and some may experience fibromyalgia or chronic fatigue.