Stress and the Brain

Stress is part of everyday life, there are even good amounts of stress that can help shape us and make us more resilient. Stressors can be as common as work or school, presenting projects or meeting deadlines, big tests or performances, even social settings can be stressful for some when there is friction. No matter where stress manifests from, when it becomes severe or chronic, it needs to be dealt with before it has a negative impact on your brain.

The brain is central to our stress response[1]. During stress, the hypothalamus and pituitary gland in the brain interact with the adrenal glands in the kidneys; this is called the HPA axis. This interacts with our autonomic, metabolic and immune system to maintain allostasis – the process of adapting to stress. Prolonged or chronic stress can negatively affect these processes, leading to wear and tear on the body and brain, referred to as allostatic overload. Health-promoting behaviours (such as the ones we’ve talked about in our tips) promote allostasis, and health-damaging behaviours (smoking, alcohol, poor diet, lack of sleep) contribute to allostatic overload.

It is well known that physical and psychological problems, such as depression and cardiovascular disease, can stem directly from too much stress. However, research has shown that how we respond to stress has important consequences for our biological and cognitive functioning[2]. When we believe we have the resources to cope with stress we experience a challenge response, where we have increased cardiac efficiency and positive outcomes. When we do not think we can cope we respond to stress as a threat, which results in reduced cardiac efficiency and impaired decision making. Over time the threat response can accelerate brain aging.

Recovery from stress is actually linked to neuroplasticity. Our brain doesn’t return to its previous state, it continually changes with experience. Resilience naturally decreases with aging, and for depression and anxiety disorders, including PTSD, adverse childhood experiences or stressful life events can make people vulnerable to allostatic overload. Research indicates that targeted therapy utilising neuroplasticity could increase resilience and improve mental health. Physical activity helps to retain the capacity for neuroplasticity and has been shown to increase hippocampal volume and blood flow in the prefrontal cortex[3]. Social connection has been shown to protect against allostatic load and dementia, also improving blood flow in the prefrontal cortex.

An additional activity that has demonstrated positive effects on the brain, and improves function in aging, is mindfulness-based stress reduction (MBSR), which can involve yoga or meditation. MBSR has been shown to increase the density of brain cells in the hippocampus, cerebellum and prefrontal cortex, which are involved in learning and memory, emotion regulation and perspective taking.

But what does all this mean?

We, as humans, can’t get rid of stress – there is always going to be some kind of stress in our lives. The key is in how we approach stress. We can view the current pandemic restrictions as a threat to our way of life, or we can view them as a challenge to learn a new way of living. When we feel overwhelmed, we can reduce our stress through regular exercise, social connection, a relaxing activity such as meditation, breathing exercises or yoga - all these have positive side effects when it comes to your brain health.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4933289/

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410434/

[3] https://www.uclahealth.org/reversibility-network/workfiles/resources/publications/mcewen-resilience.pdf