Stress (biology)

In medicine, stress is defined as one of the following:

• An applied force or system of forces that tends to strain or deform a body,
• The resisting force set up in a body as a result of an externally applied force, or
• A physical or psychological stimulus that can produce mental tension or physiological reactions that may lead to illness.

Detailed definitions

Stress can be defined as the sum of physical and mental responses to an unacceptable disparity between real or imagined personal experience and personal expectations. By this definition, stress is a response which includes both physical and mental components.

The physical responses include a host of physiological changes which are usually acute responses or chronic responses. Acute responses are approximately described by Hans Selye. Chronic responses are more complex and subtle, and have not been fully delineated.

Mental responses to stress include adaptive (good) stress, anxiety, and depression. Where stress enhances function (physical or mental) it may be considered good stress. However, if stress persists and is of excessive degree, it eventually leads to a need for resolution, which may lead either to anxious (escape) or depressive (withdrawal) behavior.

One may further appreciate from that definition that stress may derive from imagined experiences such as frightening movies. Further, the fulcrum of stress response is the presence of disparity between experience (real or imagined) and personal expectations. A person living in a fashion consistent with personally-accepted expectations has no stress even if the conditions might be interpreted as adverse from some outside perspective — rural people may live in comparative poverty, and yet be unstressed if there is sufficiency according to their expectations. Finally, when there is chronic disparity between experience and expectations, stress may be relieved by acceptance. However, since acceptance is rarely complete except in children , stress resolution by this approach is also rarely complete. It has been said that stress is often a reaction to a crisis of predictability, that the mind is solely an instrument of prediction, and that the body may be divided into a vegetative process and an integrative process.

Stressors

Any factor that causes stress is called a "stressor." There are two kinds of stressors: processive stressors and systemic stressors.

Processive stressors

"... and processive stressors are those that require appraisal of a situation or involve a high-level of cognitive processing of the incoming sensory information. Processive stressors can be experienced in the exposure to a new environment."

Systematic stressors

Systemic stressors cause a disturbance in the organism's homeostasis, as well as tissue necrosis, hypertension, and/or hypoxia. Often, both types of stressors occur simultaneously. They are usually accompanied by pain and/or intensive emotions.

Neurochemistry and Physiology

Main article: Neurochemistry

The neurochemistry of the general adaptation syndrome is now believed to be well understood, although much remains to be discovered about how this system interacts with others in the brain and elsewhere in the body.

The body reacts to stress first by releasing the catecholamine hormones, epinephrine and norepinephrine, and the glucocorticoid hormones, cortisol and cortisone.

The hypothalamic-pituitary-adrenal (HPA) axis is a major part of the neuroendocrine system, involving the interactions of the hypothalamus, the pituitary gland, and the adrenal glands. The HPA axis is believed to play a primary role in the body's reactions to stress by balancing hormone releases from the adrenaline-producing adrenal medulla, and from the corticosteroid-producing adrenal cortex.

Folklore of stress

About the time of Selye's work, it was gradually realized that such concepts as anxiety, antagonism, exhaustion, frustration, distress, despair, overwork, pre-menstrual tension, over-focusing, confusion, mourning, and fear could all come together in a general broadening of the meaning of the term stress. The popular use of the term in modern folklore expanded rapidly and created an industry of popular psychology, self-help, personal counseling, and sometimes quackery. There were a series of films in the 30s, 40s, & 50s that dealt with mad scientists playing with hormones that seem related to this folklore.

The use of the term stress in serious and recognized cases, such as those of post-traumatic stress disorder and psychosomatic illness, has scarcely helped clear analysis of the generalized "stress" phenomenon. Nonetheless, some varieties of stress from negative life events (distress) and from positive life events, (eustress) can clearly have a serious physical impact distinct from the troubles of what psychotherapists call the "worried well". Stress activates the sympathetic leg of the autonomous nervous system and the release of stress hormones including adrenaline/epinephrine, and cortisol.

Sympathetic nervous output tends to divert bloodflow to the large muscles—the body 'thinks' it has to run away from something or fight something: the so-called 'fight or flight' response of ancient evolutionary heritage—and blood flows correspondingly less to the digestive system and other organs that are not immediately needed for a response to the stimulus. We all recognise the effects: dry mouth, motor agitation, sweating, pallor, enlarged pupils, and insomnia. Our modern lifestyle tends to cause continual sympathetic nervous system activation with very little opportunity for the parasympathetic (also called 'vegetative') nervous system to activate. Capitalism, as an example, has been said to induce chronic anxiety as part of its systematic mechanism. When this sympathetic system is active, the bowel and other non-muscle organs receive good blood-flow, the pupils constrict, and the glands all function well and secrete their various compounds. Absence of the autonomic parasympathetic activation leads to poor digestion and probably also to poor healing and organ function. It is vital to take time out from our modern lifestyles to allow for rest and proper parasympathetic action in our bodies.

Whenever we encounter a stressful event, our bodies undergo a series of hormonal and biochemical changes that put as in a ‘fight or flight mode.’ Our heart rate increases, adrenaline rushes through our blood stream, and our digestive and immune systems temporarily shut down. If the stressors continue and we stay on high alert for a prolonged period of time, we experience exhaustion and burn out. None of us can avoid stress, but we can return to a state of balance and regulation through a variety of means: exercise, humor, play, music, prayer, or meditation. These activities provide calming and relaxing sensory input for stress relief, and can be selected according to lifestyle and preference. It may be that persons become so accustomed to high levels of stress that they no longer remember real relaxation, and often habits and states of mind which we develop in our strength and youth become pathogenic as we grow older.

Stress Management Techniques

The following activities, actions, and descriptions listed below, as well as any other means in relieving or reducing stress, can be coined stress management techniques. Stress management techniques allow for stress reduction through applications of exercise, medicine, personal analysis—this can effortlessly be achieved by attending therapy sessions with a psychologist, for example—or can even be as simple as devoting an increment of one's day for personal time. Stress management techniques are broadly used today as the negative health effects of a stress overload can be detrimental to one's daily functioning. As for chronic stress, the consistent application of stress over a period of time can seriously impair one's mental, physical, and even social functionings. Studies show chronic stress is extremely unhealthy in numerous aspects: those who are stressed are more suspectible to a myriad of diseases ranging from high blood pressure to forms of skin cancer, as studies within the scientific realm have most recently shown. For optimal health and wellness it is vital to undertake a stress management technique in attempts to reduce, if not ideally completely eliminate, stress or the situation that is facilitating it. Below are some methods of stress management techniques:

Meditation as a relief of stress

The history of meditation goes back even further than that of Hatha Yoga, with its origins beginning around 3000 B.C. Meditation evolved as a way for the ancient spiritual seers—known in India as Rishis—to gain direct knowledge of the nature of the Ultimate Reality. Today, meditation is recognized for its myriad health benefits, and is widely practiced as a way to counteract stress. Meditation brings together all the energies of the mind and focuses them on a chosen point: a word, a sound, a symbol, an image that evokes comfort, or one’s own breathing. It is typically practiced in a quiet, clean environment in a seated posture with the eyes closed.

As with yoga, a regular practice of meditation conditions you to bring the meditative state into your daily life. Holistic-online [www.holistic-online.com] reports that "hormones and other biochemical compounds in the blood indicative of stress tend to decrease during (meditation) practice. These changes also stabilize over time, so that a person is actually less stressed biochemically during daily activity."

In meditation, there is both effort and passive participation. One continually brings attention back to a chosen focus (effort), and simply become a witness of all that transpires (passive participation), incorporating thoughts, sensory input, bodily sensations, and external stimulus into the meditation experience. The result of centering the mind in this way is a corresponding calming and relaxing of the body, down to the cellular level, providing stress reduction, by blocking out cognitive stressors and reducing physical ones.

Relaxation Response as a relief of stress

Herbert Benson, M.D. developed a technique called The Relaxation Response, which makes the basic steps of meditation easy to understand and apply. Dr. Benson’s website offers the following steps as a simple way to begin practicing meditation:

• Pick a focus word, short phrase, or prayer that is firmly rooted in your belief system, such as "one," "peace," "The Lord is my shepherd," "Hail Mary full of grace," or "shalom."
• Sit quietly in a comfortable position.
• Close your eyes.
• Relax your muscles, progressing from your feet to your calves, thighs, abdomen, shoulders, head, and neck.
• Breathe slowly and naturally, and as you do, say your focus word, sound, phrase, or prayer silently to yourself as you exhale.
• Assume a passive attitude. Don't worry about how well you're doing. When other thoughts come to mind, simply say to yourself, "Oh well," and gently return to your repetition.
• Continue for ten to 20 minutes.
• Do not stand immediately. Continue sitting quietly for a minute or so, allowing other thoughts to return. Then open your eyes and sit for another minute before rising.
• Practice the technique once or twice daily. Good times to do so are before breakfast and before dinner. (Mind-Body Medical Institute)

Walking meditations as a relief of stress

There are more active forms of meditation as well, such as the walking meditations taught by the Vietnamese Buddhist monk Thich Nhat Hanh and Jon Kabat-Zinn of the University of Massachusetts Medical Center. Walking meditations employ the practice of mindfulness, which involves being fully engaged in whatever is happening in the present moment, without becoming involved in thinking about it. Therefore, when you walk you focus on each step, the sensation of the feet touching the ground, the rhythm of the breath while moving, and the feel of wind against your face.

This type of meditation is "portable", and can be practiced in other activities, such as driving or engaging in work tasks. Mindfulness meditation relieves stress because it relieves preoccupation with the habitual thoughts about the past or the future that perpetuate stress. As mind-body medicine pioneer Joan Borysenko, Ph.D., says, "Meditation helps to keep us from identifying with the ‘movies of the mind.’"

Another meditation technique involves guided imagery or visualizations. In this method, the meditator imagines a scene wherein he or she feels very at peace and is able to let go of all concerns and tensions. In many cases, this form of meditation is practiced by listening to guided audio instructions. Visit the online guided meditations section of the references and resources for a sampling of some free guided meditations.

Tai Chi as a relief of stress

Tai Chi Chuan, or Tai Chi for short, is a self-paced, non-competitive series of slow, flowing body movements (“forms”) that emphasize acute concentration, relaxation, and the conscious circulation of vital energy throughout the body. Though Tai Chi evolved as a martial art sometime in the 13th century, it is primarily practiced today as a way of calming the mind, conditioning the body, and reducing stress. The basis of Tai Chi is the principle of “softness defeating hardness.” Proper stance, which involves lowering the center of gravity (“sinking”), is emphasized over muscular strength as a way to access one’s innate power. Depending on the style of Tai Chi taught, there are between 13 and 108 forms that make up a set when performed continuously. As in meditation, Tai Chi employs focusing on the breath and mindfulness, or maintenance of the mind’s attention in the present moment and merging it with daily motions. Tai Chi Practitioners say moving meditation is, 10, 100, 1000 times better than sitting meditation. In the Chinese system, one works in the the world through ones productive years, but as one passes into retirement one strives to attain a near continuos meditation in one's life, cultivating one's garden.

Tai Chi works with the concept of Qi (pronounced “chee”) —a “bio-energy” that moves throughout the body via invisible energy channels called meridians. Qi regulates and maintains health in the various systems of the body by supplying healing energy to the organs. When there are constrictions in the movement of Qi due to injury, a “slumping” posture, or other problems, “dis-ease” or stress results. The muscular movements of Tai Chi remove any blockages and stimulate the Qi to flow freely.

Tai Chi is especially suited for older adults because of its low impact movements. Reported health benefits:

• Less stress and more peace of mind.
• Improved ability to deal with difficult situations.
• Improved balance and proprioception (internal body awareness).
• More strength, stamina, and suppleness.
• Improved functioning of the internal organs.
• Easier breathing and better sleep.
• Improve balance and minimize falls.
• It is self-paced and noncompetitive.
• You don't need a large physical space, special clothing or equipment.
• It is easy to do in groups as well as by yourself.
• You can add new movements as you become more proficient.
• The International Taoist Tai Chi Society provides a World Directory of Tai Chi practitioners as a way to find qualified instruction near you.

Other activities as relief of stress

Sleep

While there are many things you can do to reduce stress, the first line of defense against stress is to make sure you are getting enough sleep. Sleep restores the body systems and provides rejuvenation. Sleep-deprived bodies will be too depleted to perform the important stress-reducing physical and mental activities we have described. See Helpguide’s Getting the Sleep You Need: Sleep Stages, Sleep Tips and Aids for more information.

Cardiovascular exercise

Exercise is good for the mind, not just the body. Exercise can help with stress relief because it provides a way for the body to release tension and pent-up frustration (stress). It can also help stave off the depression that can set in when stress levels become too high by raising the output of endorphins—one of the ‘feel good’ chemicals in the brain. Any form of exercise can combat stress, but it is important that the activity be enjoyable, vigorous enough to discharge energy, and have a relaxing effect when you are finished.

Yoga

Practicing Yoga can have similar effects on the body and mind as practicing meditation. Yoga can force awareness to shift out of the mind and into the body. This transition happens through focusing on alignment of body and on breathing. There are also many poses that act as restorative yoga poses which bring the body in a conscious, awake state of rest. This not only relaxes the body but also calms the mind, helping to reduce the psychological triggers of stress. Ultimately, yoga can help to calm the activating nervous system, the sympathetic nervous system and stimulate the calming nervous system, the parasympathetic nervous system.

Spending time in nature

Psychologists today recognize the mental health benefits of spending time in the natural world. Activities done in nature tend to calm the mind and emotions, and to bring greater body awareness as a way to let go of mental stress. From taking walks in your neighborhood, to observing animals in the wild, to planting a garden, there are myriad ways to connect with the grounding and nurturing energy in nature. See the article Spending Time in Nature for suggestions on how to begin tapping the healing power of nature.

Massage Therapy

A professional massage from a trained therapist can provide soothing, deep relaxation and can improve important physiological processes such as circulation. A stress-relieving massage targets specific muscles that may be tense and painful. As the tense muscles relax, so does your overstressed mind. As massage has recently gained popularity as a stress reliever, the variety of different types of massage has changed. According to the American Massage Therapy Association (AMTA), the most common type of massage is a Swedish massage, which is specifically meant to relax and energize. Wilheim Riech proposed "body armor" as sets of muscles which rigidify in response to some stressor—he recommended sex as the release. Before visiting a massage therapist, you may want to visit the consumer section of AMTA’s website to learn more about what massage can do for you, what to expect from a massage, and how to find a qualified massage therapist.

Common causes of stress

Below is a non-exhaustive list of common stressors in people's lives:

• Bright light
• Elevated sound levels
• Events: births, deaths, reunions, weddings, divorce, moving.
• Responsibilities: Unpaid bills, lack of money
• Work/study: exams, rush hour traffic, project deadlines
• Personal relationships: conflict, deception
• Lifestyle

See also

• Homeostasis

External links

• Stress Relief - Tell Me About Stress Articles and Resources
• Stress articles, resources and websites
• Stress: University of Milan
• Scientific American Magazine (September 2003 Issue) Taming Stress
• The UK National Work-Stress Network