Stress changes the chemistry of our bodies in ways that can have long term significance. This article looks at the physical changes induced by stress that can lead to stress “addiction” as well as the long term consequences of chronic stress.
The Normal Response To Stress
Our bodies have very complicated regulatory systems that rely on the interaction of messenger chemicals such as neurotransmitters and hormones. Neurotransmitters are chemicals produced by the nervous system that facilitate the transmission of an impulse across a junction between nerves or between a nerve and its target tissue. Hormones are substances, secreted by a variety of glands, that travel through the blood stream to trigger specific activities by the tissues that are sensitive to them. When we experience a stress, it doesn’t matter whether the stressor is real or imagined, physical or psychological; our bodies respond in the same manner.The perception of stress causes a region of the brain, the locus coeruleus, to increase its production of the neurotransmitter, norepinephrine (NE) or noradrenaline. When the locus coeruleus is activated in this way, it stimulates a group of hormone-secreting glands: the hypothalamus, the pituitary and the adrenals. The adrenal glands secrete higher levels of NE and the hormone, cortisol.
The locus coeruleus also stimulates the sympathetic nervous system and inhibits the parasympathetic nervous system. We go on alert, feel “wired”, and are unable to relax and digest food properly as a result.
NE raises the heart rate, blood pressure and blood sugar to prepare us for the “fight or flight” response. Cortisol has a broader range of action; it does the following:
- mobilizes and replenishes energy stores by causing blood sugar to increase and fat to be deposited in specific areas such as the abdomen
- increases arousal and vigilance
- focuses attention and improves memory
- inhibits growth, reproductive and immune system functions.
All of these changes help us to get through the rough times; they are adaptive in a positive way for short periods.
The Response To Chronic Stress
When stress is not relieved, our bodies continue to adapt to what they perceive as the “new normal”. If the new normal continues for a long time, these adaptations become problematic. Here’s why.
NE and cortisol have buddied up to change the amount of glucose in the blood stream and cortisol alters the amount and manner of fat being deposited. These changes can predispose us to conditions like obesity, diabetes and cardiovascular disease.
NE on its own will keep the heart rate and blood pressure elevated; these are also risk factors for cardiovascular illness.
The dual action of NE on the sympathetic and parasympathetic nervous systems keeps us from relaxing; sleep and digestion suffer as a result. When sleep and digestion become disordered over sustained periods of time, additional maladaptive hormonal changes may occur.
Cortisol suppresses the activity of the immune system, making us vulnerable to infections and abnormal cell growths such as cancer.
How Chronic Stress Can Be Like An Addiction
Our bodies are “programmed” to operate within certain parameters. When the parameters are normal, good health results. When the parameters become shifted because of unrelieved stress, illness will eventually occur.
The parameter shift causes our bodies to perceive a new “normal”, like a thermostat that has been reset to keep the temperature in a building at a new level. Over time, the tissues that are being activated by the effects of NE and cortisol increase the number of receptor sites for the messenger chemicals. The tissues become accustomed to a higher level of stimulation.
When the level of stimulation falls, we feel “off”. The amount of messenger chemical stimulation is no longer in the range the target tissues have adjusted to. We don’t want to feel off, so we change our behaviour in a way that brings our stress level back into the range that will result in the messenger chemicals being secreted in the amount that feels normal to us.
We can do this by taking in stimulants like nicotine and caffeine or by engaging in thrill-seeking, high risk behaviour. If life isn’t bringing us too many thrills, we create substitute pressures with excess work, or relationship conflicts, or increase our sensitivity to these by increasing our level of fatigue through inadequate rest and sleep.
Like any addiction, the inevitable result of these stress-promoting behaviours is a long term impairment of health as the negative effects of chronic stress take hold.
In the next article, I’ll look at how stress addiction leads to a condition NDs call “adrenal fatigue” and outline some simple steps for restoring a healthy balance.
If you think you could do a better job of managing your stress, check out this article for some tips and consider seeing an ND for ongoing guidance and support.