The autonomic nervous system regulates the body functions as situations require. Recovery and healing systems are most active during sleep. After lunch it is important to digest the food and use the nutrients efficiently. When facing imminent threat, the immune system and food processing are not important. They are shut off, to use all the possible energy for muscles that are needed in the fight.
The autonomic nervous system works largely unconsciously. It is responsible for many vital functions such as blood pressure and temperature regulation, digestion and function of the adrenal cortex. It works through the neural network that controls the heart and other organs. The autonomic nervous system keeps us alive without us knowingly doing anything about it.
The autonomic nervous system consists of two complementary parts, the sympathetic and parasympathetic. When active, the parasympathetic nervous system slows down the heart beat, enhances digestion and healing. It strives to calm the body down and keep the vital functions stable.
The sympathetic part is responsible for preparing the body for action, and it´s fibers can innervate tissues in almost every organ. The sympathetic nervous system activates in stressful situations and in hard physical strain.
The both parts of the autonomic nervous systems normally work in good cooperation, but as a seesaw. When the other gets active, the other slows down. For instance in acute stress reaction the sympathetic nervous system works in full speed in an instant. The working of the parasympathetic part seizes and e.g. digestion almost stops. A perfect operation of the sympathetic and parasympathetic part enable an accurate and fast regulation of our internal mechanisms in any situation.
The fight or flight response is a way for us to cope in a rapidly escalating threatening situation. At the time of cavemen the case was normally quickly closed, the fights did not last for weeks or months. For a today´s human the stress reaction might be a permanent state, and the parasympathetic nervous system does not have the chance to return our body to rest.
In long term stress the cortisol levels in our body are continuously high
Chronic stress keeps the hypothalamic–pituitary–adrenal axis active. It is like an idling motor, pumping stress hormones such as cortisol to our system.
Cortisol helps us to confront the threat but it simultaneously shuts down the immune system. From the evolution point of view this made sense: if a crocodile attacks we can shut down all the functions in the body that are not needed to flee or fight. The immune defense weakens when we are continuously stressed, and this might lead to a series of infections. The stress factors also play a role in the development of autoimmune diseases, heart and blood vessel diseases and cancer. Continuous boosts of adrenaline can harm blood vessels, raise blood pressure and increase the risk of cardiovascular diseases.
Worrying and fear increase our mental load and can further activate the sympathetic nervous system. Physical symptoms persist, recovery via rest and sleep further slow down.
Heavy cognitive and emotional load during recovery from an illness might be as bad for our body as physical exercise. Our body would choose to put the work aside when being ill.
Chronic Stress affects memory, concentration and appetite
In a state of chronic stress the brain thinks that a physical fight starts any time. With cortisol our body works to have a lot of energy available. It enhances appetite and extra energy storing with might lead to weight gain.
Cortisol is also released to hippocampus that is central in memorizing and learning. A stressed out person has difficulties in learning and emotion regulation. There are often concentration difficulties and memory problems.
Chronic stress can not go on forever without consequences. Burnout is a severe disturbance in our vital mechanisms. Simultaneous psychological, neural, metabolic and immune system collapse might be so total, that a complete recovery is very slow or even impossible.
The best cure for burnout is prevention. It can be difficult to understand the graveness of the situation. People tend to compare themselves and their working rhythms to others and to pretend that everything is fine. Just a moment before collapsing things might seem normal from the outside.
Talk with friends and family, colleagues, your superior or a health care professional if you feel that the load is too high.
Sleep is a good indicator.
Sleep, brain and stress
When the life is in balance, we recover from acute stress reactions and also longer burdensome periods. These take often place in life changes: a newcomer in the family, moving house, study or work project that is exceptionally demanding. We overcome these challenges when the amount of recovery is sufficient.
Sleep is our most important recovery function and an indicator of balance. Weeks and months with disturbed sleep is a sign of stress, and sleep deprivation further lowers down our resilience.
The brain needs sleep. During sleep many things take place that the sleeper is not aware of. A daily cleanup is made in order for us to feel physically and mentally well.
There is no health without sleep. The importance of proper recovery becomes clear after a period of poor sleeping. At worst the life is just coping. Unfortunately this is reality for so many, that we have begun to think it is normal not to sleep enough. But it is not.
When we most nights sleep well and feel brisk in the morning, our body and mind are always prepared to perform well. We are in balance.
The complete set of 5 articles:
- Part 1: Fight or flight response
- Part 2: Chronic stress – The brain concludes that we are continuously in danger
- Part 3: Tools for long term and continuous stress measurement
- Part 4: The Moodmetric ring stress measurement and understanding the data
- Part 5: The Moodmetric measurement in preventive occupational health