How to grow a bigger brain in 16 weeks
Exercise helps generate new cells in your brain, supporting learning, memory, mood, and more. But how much exercise is needed?
Sponsored Story
Free webinar
The power of exercise for mind, mood and mental wellbeing on 9 September 2025.
Combat misinformation. Get evidence-based advice about the motivating benefits of exercise for brain health and mental health. Held in partnership with AUSactive.
Did you know that exercise can help you to grow new cells in your brain?
Exercise is one of the best things you can do for brain health, with benefits ranging from decreasing dementia risk to managing depression.
Even more surprisingly, the brain-boosting benefits of exercise are achieved more quickly than you might otherwise assume...
But first, why is exercise good for the mind?
Your amazing brain – comprised of over 100 billion cells – is neuroplastic.
Neuroplasticity, in simplest terms, is your brain’s ability to change. It can change by building new cells, forming new connections or changing chemical activity; all of which influences your brain function.
Exercise drives neuroplasticity in the brain. Put another way, exercise can help your brain to grow new cells and form fresh connections – in ways that are very helpful.
How exercise can build a ‘bigger’ brain in just 16 weeks
Some of the amazing mind and mood benefits of exercise may be attributed, at least in part, to a very special region of the brain: the hippocampus.
Despite its somewhat funny-sounding name, the hippocampus looks after some serious functions! For example, it is critical to our learning and memory systems and is involved in many neural pathways that help to regulate our mood.
Left to its own devices, the hippocampus shrinks at a small but steady rate across our lifespan. Starting from the age of 25, volume losses in the hippocampus march on at a rate of 0.38% per year.
However, just like exercise can build new muscles, exercise can also help to grow new cells in the hippocampus. Thanks to the high level of neuroplasticity of this part of the brain, it’s possible to slow or even reverse age-related hippocampal volume loss.
In as little as 16 weeks!
Other ways your brain can benefit from exercise
The many benefits of exercise to the brain don’t stop there.
Even moderately vigorous exercise on a regular basis may improve memory and the processing speed of your brain. And higher cardiorespiratory fitness has also been shown to increase volume in the frontal cortex. This is a region of the brain that’s essential for complex thinking and emotional regulation.
Critically, exercise is a key risk factor for dementia and plays a role in protecting your brain from ageing – well before dementia symptoms emerge. A recent study conducted by the Thompson Institute’s Healthy Brain Ageing team looked at modifiable risk factors for dementia, including exercise.
The researchers found that older adults with higher dementia risk, such as low physical activity, were associated with lower white matter volume – the critical system that connects different brain regions to each other. At the same time, higher risk was associated with less balanced electrical brain activity.
These relationships were found well before any symptoms of dementia had appeared, reflecting how our lifestyle choices, like how much we exercise, are protecting the very structure and function of our brain.
One study found that a cardiorespiratory exercise program (consisting of 150 minutes of movement each week) resulted in significant improvements to blood flow and connectivity within the hippocampus. Furthermore, participants in this study were aged 70 to 85 years, highlighting the important message that:
It’s never too late to start
Given all these motivating reasons to exercise, the good news is that it’s never too late to start. Take some inspiration from a study that looked at the effects of exercise in a group of 120 older adults.
Half of the group were given a moderate intensity walking program to follow. The other half were given basic stretching exercises.
After one year, the walking group showed increased volume in a brain area called the hippocampus. The hippocampus is important for memory, mood and spatial awareness.
The study’s findings are supported by other research showing that exercise is important in the quest to have healthy brains for life. Higher levels of aerobic fitness have been shown to benefit areas of the brain beyond the hippocampus and reduce risk of cognitive decline.
How much exercise do I need?
While there’s no perfect one-size-fits-all approach, there are general guidelines that can be helpful. (Noting that these are not a replacement for individualised advice and a GP check-up is recommended before commencing new exercise if you are over the age of 40 and haven’t exercised for some time.)
For adults aged 18-64 years, Australian physical activity and sedentary behaviour guidelines recommend:
Be active on most, preferably all days, to achieve a weekly total of at least 150 minutes of moderate to vigorous activity.
Do muscle-strengthening activities at least two times per week. It doesn’t have to be lifting weights; body weight exercises like push-ups or household tasks that involve lifting, carrying, or digging also count.
Minimise and break up prolonged periods of sitting.
Recommendations for adults over 65 years are:
Be active on most, preferably all days, with at least 30 minutes of moderate activity per day.
Incorporate muscle-strengthening activities.
Be as active as possible.
Sound like a lot? Don’t be discouraged. Even a little exercise can be beneficial and there’s magic in starting small to build habits slowly. Check out our article on how to create habits that stick and the extra brain benefits of exercise for more tips on how to get going (literally!).
For now, the science is clear. Exercise not only makes us feel good by elevating our mood; it is good – for our brain health now and into the future.
