Most of you already know that stress can be detrimental to health (both physical and emotional). Many different statistics are cited which support this. One figure is that 43% of all adults in the US suffer some adverse effects from stress; 75-90% of all doctor visits are due to stress—related ailments and more than 50% of deaths in the US have been associated with the effects of stress and the unhealthy behaviors some use to cope, such as smoking, alcohol, drug use and overeating. The physical effects of stress have been associated with exacerbation of a large number of health problems including cardiovascular disease (angina, heart attacks), hypertension, substance abuse disorders, heartburn, migraines, tension headaches, back pain, insomnia, TMJ, peptic ulcer disease, chronic fatigue, irritable bowel syndrome, autoimmune disorders, immune suppression, impaired memory, depression, infertility, asthma, impaired concentration and reduced healing after surgery.

How Does Stress Affect The Body?

The body has evolved a system to respond to immediate threats to its survival ("acute stressor") such as being attacked by a predator. The system includes hormones and neurotransmitters which together cause a cascade of events in the body called the "Fight or Flight" response. Some of the hormones involved include adrenaline (aka epinephrine or EPI), noradredenaline (norepinephrine) and cortisol. NE also functions as a neurotransmitter in the Autonomic Nervous System (ANS) which regulates a number of internal functions such as heart rate, respiratory rate and digestion. The ANS has two main opposing branches called the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS). The SNS is associated with the "Fight or Flight" (stress) response while the PNS is associated with calming back down after the threat is gone (relaxation response).

"Fight or Flight" or "Stress" Response

When a threat to survival (such as attack by a predator) appears, it causes a number of physical effects which are needed to allow us to FIGHT or FLEE to survive. These effects include heightened mental alertness, pupil dilation, increased heart rate, increased blood pressure, increased respiratory rate, increased blood sugar, increased blood flow to large muscles, increased rate of clotting (to make an injury more survivable,) fluid retention (to reduce risk of shock during injury), decreased blood flow to digestive tract, hyper vigilance to ones' surroundings, increased muscle tension, decreased blood flow to non-essential organs such as the immune system and small muscles in hands, feet and lips.

Physical Effects of "Stress"

1. racing heart, palpitations
2. nausea
3. dizziness & lightheadedness
4. rapid, shallow breathing & hyperventilation
5. sweating, flushing
6. muscle tension
7. tremor
8. numbness & tingling in hands, feet and lips
9. jaw clenching
10. headache
11. back ache, neck ache

The initial (alarm) phase of the fight or flight response may last approximately 15 minutes while the EPI and NE are being degraded and eliminated from the blood stream. If another threat comes along (or the same threat is still there) then more NE and EPI are released and the response is perpetuated.

The Relaxation Response is initiated by the Parasympathetic Nervous System when the threat is gone and this causes many of the opposite effects in order to re-establish homeostasis (reach baseline again). These effects include decreased heart rate, decreased blood pressure, decreased respiratory rate, decreased muscle tension, restored normal clotting time and decreased mental alertness/hyper-vigilance.

In physically stressful/threatening situations, the threat causes us to physically exert ourselves (by fighting or running) and this physical exercise may help discharge the "nervous energy," and decrease muscle tension and restore calm. In modern days, most of the stressors we experience are not physical threats and don't invoke a surge of physical activity. Instead we try to cope with the stress mentally. This may be all the more reason, as studies show, that exercise helps relieve stress. With our modern sedentary lifestyles, finding time for exercise is even more important.

Another component to the stress response is the cortisol system. Cortisol is a steroid hormone secreted by the pituitary gland in response to stress. The pituitary gland is signaled by the brain (through the hypothalamus via the "HPA Axis"—hypothalamus-pituitary-adrenal gland axis) that a threat exists, which causes the pituitary gland to release cortisol. Cortisol is known to affect many systems in the body including immune function, inflammation and wound healing. Its role is being studied in depression, obesity, dementia and many other conditions. Take a moment to identify which physical effects you experience next time you are under stress. You may want to jot them down or circle them above.