HOW STRESS AFFECTS YOUR BRAIN
Stress is a normal and necessary part of life. Long-lasting (chronic) stress, however, is bad for your body and your brain health. The challenge is to manage your stress levels and make it work for rather than against you.
The brain views stress as a potential threat, causing both it and the body to react and either deal with the threat (fight) or avoid it (flight).
This is called the stress response. While some stress helps sharpen the mind, long-term (chronic) stress can harm your brain health.
Chronic stress changes the brain’s structure. It kills brain cells and shrinks the brain, affecting memory, emotion, self-control and learning.
It damages synapses (connections in the brain that are needed for optimal brain functioning), accelerates the ageing process and reduces the development of new brain cells.
It can even increase your risk of developing a brain health challenge like depression.
BOOST YOUR KNOWLEDGE
In emergencies requiring a short-term response, our bodies automatically increase production of stress hormones such as adrenaline and cortisol which help our bodies react to the emergency. This process is known as the adaptive stress response. It’s adaptive because when used correctly, it keeps us alive.
The adaptive stress response begins in the brain. When you experience something stressful, the amygdala, which is involved in processing emotions such as fear, sends an instant distress signal to another region of the brain called the hypothalamus. The hypothalamus then triggers the body to react in certain ways to protect itself. This reaction is known as ‘fight or flight’, and as you can imagine, is extremely important for our survival.
The fight or flight response requires no thought or decision making from us and is often referred to as an automatic process. Think, for example, about a time where you saw something you thought was dangerous out of the corner of your eye and jumped to get away from it (flight) or immediately turned to face it (fight).
As important as the fight or flight response is, it is equally important that it gets ‘turned off’ once the threat has passed and we are no longer in danger. The turning off also happens through the hypothalamus once the brain determines that the threat is over and signals the body to ‘rest and digest’.
The adaptive stress response has two phases:
SAM provides an immediate short-lasting response, such as an increase in alertness and vigilance.
Two hormones, adrenaline and noradrenaline (norepinephrine), are released into the bloodstream. They ready the body for action and result in:
• an increase in heart rate and blood pressure;
• increased sweating to cool the body;
• faster breathing to raise the oxygen supply;
• increased sensory perception;
• increased metabolism; and
• a dilation of the pupils to improve vision.
Today, most of us rarely need to use this type of stress response to make it through a typical day — but life still offers a variety of mental stresses. If the stress is temporary, the stress response would end, giving the body and brain time to rest and recover.
If the threat is short-lasting, the hypothalamus, pituitary and adrenal glands or HPA axis is triggered as the adrenaline surge from the first phase of the stress response slows down. The HPA axis system also starts in the brain – the amygdala talks to the prefrontal cortex (which is the part of the brain that assesses how serious a situation is and controls our reactions towards the situation) which signals the HPA axis to respond.
When the stress response is triggered for a longer time, the body releases cortisol, which allows the brain to think clearly, sends energy to muscles, heightens the senses and keeps the body on high alert. Cortisol also regulates the HPA axis, which itself continues producing cortisol during long-term stress.
When the stress response is no longer helping us
If the stress does not go away and the stress response is not ‘turned off’, the HPA axis can go into overdrive and begin to produce too much cortisol. This is known as chronic stress. Over the long term this negatively affects concentration, memory and emotions. It can also cause lowered immunity and inflammatory responses which are bad for the brain and body.
Over long periods of time, increased levels of cortisol also increases activity and the number of neural connections in the amygdala (heightening fear). As cortisol rises, electric signals in the hippocampus deteriorate and fewer new brain cells are made (impacting memory, learning and affecting your ability to control stress). The chronic stress response also suppresses the prefrontal cortex (reducing concentration, judgement, social interaction and decision-making). At this point, the stress response is no longer adaptive and is starting to negatively affect our brains and bodies.
The areas of the brain and body involved in the stress response are not able to tell the difference between a physical threat, like a snake, and something which is a perceived or emotional threat, like being stressed about not being able to pay your bills or not feeling safe in your daily life. This is why many South Africans and people around the world find themselves in a state of chronic stress, even when there is no physical threat to their lives. In other words, if you think you’re in danger, your stress response will be triggered. How stressed you feel and how long it lasts depends on the nature of the stress.
Stress response in depression and anxiety
In depression and anxiety, two common brain health challenges, the normal stress response is disrupted. It is not yet known whether a disrupted stress response causes depression and anxiety, or whether existing depression and anxiety causes a disrupted stress response. Either way, chronic stress is associated with reduced levels of serotonin, dopamine and other neurotransmitters, which have been linked to these brain health challenges. When these neurotransmitter systems are working normally, they regulate sleep, appetite, energy, mood and emotions. Disruption of these systems affects a number of functions including sleep, clear thought and memory.
Early childhood adversity
Different regions of the brain become fully developed at different stages of life, eg the hippocampus at 2 years, the amygdala at 20 years and the prefrontal cortex at 25 years. Experiencing high levels of stress during early childhood and even adolescence and adulthood may impact the brain’s development, affecting how a person responds to future stress and increasing their vulnerability to brain health challenges like depression and anxiety.
What is a stressor?
Stressors are anything that cause stress. They are physical or emotional events that result in the release of stress hormones such as adrenaline. Stressors can be anything from relationship troubles and work pressure to inconveniences like losing your keys or being stuck in traffic. People, places, objects and situations – real or imagined – can be stressors. A difficult colleague, a busy shopping mall, losing something you treasure or a car accident can all be stressors. The effect of a stressor depends on you, ranging from mild to severe stress. For someone suffering from depression or anxiety even leaving the house can be stressful.
What is a trigger?
A trigger is something that sets off a flashback or feeling that takes you back to a traumatic event. Triggers are very personal; different things trigger different people. People may react to the trigger as though the event is happening in the present and with the same emotional strength. People may begin to avoid situations and things that she/he thinks triggered the flashback.
HOW STRESS AFFECTS YOUR BODY
While sources of stress are different for different people, major life changes — divorce, death,
illness, moving, changing jobs — are typically stressful, and the numerous strains of daily living
can quickly add up as well.
HOW TO MANAGE STRESS
Once you have recognised the sources of stress in your life and the emotional and/or physical reactions you have to them, the key is to find ways to minimise or manage those reactions. Read more about the different types of stress and get tips on how to manage them here.
Look for creative solutions
• Would carpooling help reduce stress related to commuting?
• Can home chores be rearranged or taken over by others?
• Would hiring a babysitter for a few hours a day help?
Try to keep things in perspective
• Let go of things beyond your control.
• Cry if that helps you feel better.
• Think about how you would advise a friend in a similar situation.
• Imagine the worst that could happen in any given situation, the likelihood that it will occur, and how you would handle it if it did.
• Consider whether you are likely to even remember the stress-producing event a few years down the road.
During extremely stressful situations, such as the death of a family member, take time to experience your feelings of sadness and loss: they are a necessary part of the grieving process.
When to call a professional
If you feel you cannot cope, consider talking to a therapist, psychiatrist or a clergy person. This may be particularly helpful if you cannot identify the cause of the stress, but have troublesome symptoms. Longstanding conflicts in a family, marriage or job may also be relieved through counselling.
Call your doctor if:
• you are experiencing feelings of hopelessness;
• you are abusing alcohol, drugs or food; or
• your symptoms are interfering with working, eating or sleeping.
Seek immediate care if stress makes you think about harming yourself or others.