The stress reaction is produced by your body's autonomic nervous system (ANS), which controls functions that happen more or less automatically in your body, like respiration, heart rate, and digestion. The sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) are both parts of the ANS, and they act in opposition to one another. The SNS generally increases physiological arousal and creates the "fight-or-flight" response, while the PNS generally decreases physiological arousal and is responsible for calming your body down after a stressful incident.
In times of stress, the SNS stimulates the adrenal glands to increase the amount of noradrenaline, a neurotransmitter, they secrete into the bloodstream along with another, more powerful neurotransmitter, adrenaline. These neurotransmitters affect the entire body, and their effects last for hours. The adrenal glands also secrete cortisol, the primary stress hormone, which increases organ sensitivity to adrenaline and noradrenaline. These events take place through a complex series of interactions between the hypothalamus, pituitary gland, and adrenal glands, which together constitute the HPA axis.
- Increases your heart rate
- Elevates your blood pressure
- Increases energy supplies (glucose and fatty acids) in the bloodstream
- Increases blood flow to the liver and skeletal muscles while constricting smaller vessels
- Increases sugars (glucose) in the bloodstream
- Enhances your brain's use of glucose
- Heightens your immune system
- Increases availability of tissue-repairing substances
- Suppresses the digestive system
- Inhibits growth processes
- Suppresses the reproductive system
The PNS is responsible for recuperation and allowing your body to return to a balanced state, known as homeostasis, after stress.
Originally the fight-or-flight response of the SNS protected us against threats from predators and other aggressors. It was designed as a temporary response to occasional threatening situations, and when the situation had been resolved the body's PNS took over, returning the body to homeostasis in what may be termed the "relaxation response."
But times have changed. Now, stressors may be anything from high-pressure jobs, to being stuck in traffic, to living on a tight budget. These sorts of stressors aren't temporary and infrequent: they're ongoing. We experience them day in, day out. If you are very frequently stressed, your body is subjected to a constant deluge of stress hormones and kept in a state of physiological arousal. You can end up becoming chronically stressed by the endless stream of stressors you face in the course of a day. This chronic stress can literally wear you out, and your body can become exhausted.
Chronically high levels of stress can:
- Lead to hypertension
- Increase levels of LDL ("bad") and decrease levels of HDL ("good") cholesterol
- Impair cognitive performance
- Suppress thyroid function
- Decrease muscle tissue
- Create blood sugar imbalances like hyperglycemia
- Decrease bone density
- Suppress the immune system
- Increase abdominal fat
In the long run, being chronically stressed can lead to heart disease, kidney disease, and stroke.
The Relaxation Response
The relaxation response of the PNS allows ANS functioning to return to normal. The body moves from a state of physiological arousal, including increased heart rate and blood pressure, decreased blood flow to the extremities, slowed digestive functioning, and increased levels of stress hormones, to a state of physiological relaxation. Your heart rate, blood pressure, blood flow, digestive functioning, and hormone levels return to their normal state.
Your fight-or-flight reaction occurs automatically and without any effort on your part. But under conditions of chronic stress, the relaxation response may never be activated. To undo the negative impact of ongoing stress, you need to consciously elicit the relaxation response.
Fortunately, there are many ways to bring the stress response under control. You can seek out support from family, friends, or professional counselors. Aerobic exercise, like running, cycling, and swimming, is usually an effective stress reducer. You might find that activities as spontaneous and unstructured as singing, gardening, playing with kids, or having sex are sufficient to put you into a relaxed state of being. Some people find that having a good cry relieves their stress. Or, you might find you need to use more structured approaches to destressing, such as meditation, deep breathing exercises, yoga, t'ai chi, self-hypnosis, and guided imagery.
Deep breathing is popular, effective, and easy-to-do stress reliever that you can practice at home or at the office. Try the following: sit in a comfortable position with your feet flat on the floor. Relax your shoulders. Exhale slowly through your nose, counting to five. Tense your abdominal muscles to help empty your lungs. At the bottom of your exhalation, pause for two counts. Now inhale slowly while counting to five. Expand your belly as you breathe in. Pause for two counts at the top of your breath, close your eyes, and begin your exhale. Repeat 5-10 times.
Whatever method you chose, it should produce a feeling of calm and deep well-being in you. Once you experience that feeling, you'll probably find that you want to return to it again and again, making it easier to acquire the good habit of relaxation.
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