Dr Sarah McKay will tell you that the most common question she hears from women is also the least useful one. What is wrong with my brain? She is an Oxford-educated neuroscientist, founder of Think Brain and The Neuroscience Academy, presenter on ABC Catalyst and the author of The Women’s Brain Book, Baby Brain and Brain Health For Dummies. She has been a neuroscientist since 1993, when she fell in love with the subject in a first year undergraduate lecture, and she has spent the years since translating brain research into something people can actually use. So when Catherine raised the widely repeated idea that the ageing brain shrinks, Sarah did not soften her answer. No, your brain is not shrinking.
Some menopause research actually shows grey matter volume increasing across the transition. Other research shows very little change beyond what ageing alone would explain. The volume loss we do see, through adolescence and first pregnancy, is a streamlining and refinement of connections rather than a decline. Sarah is careful to point out that a big part of what she tries to do is counter the assumption that the brain is inherently broken, or inevitably will be. She would rather learn something new about it than berate herself for not knowing it sooner.
A map, not a diagnosis
What Sarah offers instead is the most useful thing in the conversation, and it asks nobody to become a neuroscientist. Picture your brain inside your body, inside your world, and ask what information it is receiving and making meaning of. That information arrives from three directions. Bottom up is the body talking to the brain: sleep, hormones, stress physiology, inflammation, movement, nutrition, pain and energy. Outside in is the world shaping the brain: relationships, caregiving, work, culture, safety, expectations, social connection and cognitive load. Top down is the mind shaping experience: attention, beliefs, predictions, identity, self-talk and what we think our symptoms mean.
Across puberty, cycles, pregnancy, postpartum, perimenopause, menopause and ageing, all three are always at work. Which is why Sarah swaps the question. Not what is wrong with my brain, but what is my brain responding to, and which system needs support first?
Brain fog is a systems puzzle
Applied to brain fog, the map changes everything. Oestrogen helps set the thermostat in your brain, and as it shifts the thermoregulatory zone narrows, so a small rise in body temperature gets read as an emergency. If that happens overnight, sleep architecture fractures. Waking once at 3am is not great. Waking for weeks or months on end is different. As Sarah puts it, it does not take long until you are lying there thinking, I am always awake, and then you will find something to worry about. Tired but wired slides into hypervigilance, and hypervigilance slides into anxiousness, which disrupts sleep further.
Alongside that, oestrogen is one regulator of how neurons take up glucose to make energy, so thinking can feel slower and more effortful. Brain networks also become less specialised with age, so reaching a solution takes a little more mental labour. None of it is decline. All of it is a system under load.
The input almost nobody counts
Then there is the piece that surprised Catherine most. Research shows that a phone face down on the table still drains you, because the effort of not looking at it consumes working memory. Sarah’s own view is that mobile phones have reached a level of salience close to that of a newborn baby. Her solution is refreshingly physical: a small device on her fridge that blocks apps until she walks over and taps her phone against it. Friction, deliberately restored.
Why you cannot think your way out
Sarah’s most contrarian point is worth sitting with. Knowing how the brain changes does not mean you can think your way into changing it. Using your thoughts to change your thoughts, she says, is the hard way around, and often the road to rumination. Change an input instead. Move your body into a different environment, the way she did in Antarctica, where her anxiety simply faded because life became linear.
Sarah leaves the audience with three golden nuggets:
What is draining my brain this week?
What is nourishing my brain this week?
What is one thing I can change?
Not a full renovation. One thing. Get it out of your head and onto pen and paper, and Sarah guarantees you will come up with a far more strategic plan, and it will change your brain.
Watch the full conversation on YouTube.
Find Out More About Dr Sarah McKay
🌐 Website: https://www.drsarahmckay.com
📸 Instagram: @drsarahmckay
📘 Facebook: Your Brain Health