IT'S perhaps a bit of an understatement to say that 2020 has been a bit stressful. We started with bushfires, then COVID-19 came along. We've had demonstrations against police brutality and Aboriginal deaths in custody, and increasingly urgent conversations about climate change. And who knows what the next few months with bring?
As a biomedical scientist, I can't help but wonder what health impacts we'll see - not just as due to smoke exposure or viruses - but from the long-term stress associated with all these events.
Stress isn't necessarily a bad thing. Short-term stress helps us adapt and survive. If you're being chased by a tiger, the stress response, or "fight or flight" response, helps you respond (and hopefully survive). These stress responses are controlled by interactions between our nervous system (brain) and our endocrine system (hormones), via something called the hypothalamus-pituitary-adrenal (or HPA) axis.
When we're stressed, the HPA axis is activated, and signals pass from the brain to the adrenal glands, which release a hormone called cortisol. Cortisol, alongside adrenaline, helps provide the burst of energy we need to escape the tiger.
While short-term stress responses are essential for survival, long-term stress is less helpful. The problem with the HPA axis is that it can't tell the difference between an immediate threat, like the tiger, and the long-term stress caused by things like months of bushfires or isolation due to COVID. When we're under chronic stress, our HPA axis keeps being activated, and we keep producing those stress hormones all the time.
Research has now shown that chronic stress and excess stress hormones can actually change the structure of our brain. It can kill some of our brain cells, and shrink parts of the brain like the prefrontal cortex, which is responsible for planning and problem solving and complex functions. If you've noticed that you feel depressed or more irritable, have trouble remembering things, or just feel like you can't think as clearly as usual, these are all things that can be caused by chronic stress and increased cortisol.
While 2020 will be over soon, there's no guarantee that 2021 will be any better. So what can we do about all this stress? Exercise, sticking to a regular daily routine and getting enough sleep can help regulate the HPA axis and reduce those stress hormones. And yes, it's been said a million times, but talking to people is important and can help.
Dr Mary McMillan is a lecturer at the School of Science and Technology, University of New England.