Health

If you can do these 5 things in your 30s, your brain is in great shape

David BenjaminOctober 16, 2025

‘We often think about brain health as a concern for later life,’ says brain and cognition expert Natalie Mackenzie. She’s right: It’s something we associate with our parents or grandparents, filed away under ‘things to worry about after 50.’ But, Mackenzie asks: ‘What if the actions you take in your 30s are setting the stage for your cognitive future?’ She describes your 30s as a critical decade, juggling a demanding career, family life, and personal ambitions. And though many have finally gotten into the stride of life, bidding adieu to the learning curve of our 20s, it’s also when the first subtle signs of cognitive strain can appear if left unchecked. Your brain is operating at its highest capacity, after all. Think about it this way: you wouldn’t neglect your physical health, so why would you ignore your mental health? (Picture: Getty Images)

Thankfully, Mackenzie says that, at 30, our brains are typically in prime condition. We’re not too far away from the final finishes of frontal lobe development, so this time is a ‘window of opportunity to understand our brain and cognitive functions.’ According to the expert, the key is understanding what ‘good shape’ looks like and knowing how to keep it that way. ‘This isn’t about gimmicks or quick fixes,’ she says. It’s about building sustainable habits that protect your most valuable asset. ‘Far too many people only start thinking about this part of their body much later down the line, even though changes are happening inside the brain now.’ For example, Alzheimer’s — the most common cause of dementia in the UK — shows up in the brain decades before symptoms show. ‘The earlier you start thinking about it, the better,’ warns Mackenzie (Picture: Getty Images)

‘Your 30s are a fascinating time for cognitive function,’ adds the expert. While the intense growth and change of your teens and early twenties have settled, your brain has now reached a period of mature efficiency and reliability. ‘Cognitive strengths such as reasoning, memory, and problem-solving are typically in their prime,’ she says. However, the environments around us have changed considerably, and the ‘demands of the modern world are really pushing the performance boundaries.’ So, how can we keep our brains in tip-top shape, and what exercises help us to do so? Here, Mackenzie shares five self-tests that measure the state of your brain — if you fly through them all and you’re in your 30s, you’re in remarkable shape (Picture: Getty Images)

Remembering everyday details

‘If you can visit the supermarket without a list and come home with nearly everything you intended to buy, your memory is working well,’ states Mackenzie. Similarly, if you can remember key points from an hour-long presentation you saw at work last week (extra points if it was especially dull), or the plot of a book you finished recently, this reflects healthy episodic memory (Picture: Getty Images)

Working memory

‘Working memory is your brain’s mini notepad,’ explains Mackenzie. Research reveals that by age 30, most healthy adults can reliably hold about seven digits in mind. This is called the ‘magic number 7′ and is why so many phone numbers are structured that way. Again, extra points for those who can remember their standard 11-digit mobile number (of course, you only need to remember nine when you factor in the ’07,’ but it’s still two more than seven). In lab based memory tests, like the digit span, Mackenzie says that adults aged 25-34 typically recall between six and eight numbers in sequence before making a slip (Picture: Getty Images)

Learning and recalling words

Next up, Mackenzie suggests another classic test: reading a list of 12 unrelated words twice, and checking how many you can recall after one minute. Apparently, normative data in this age group suggests it’s healthy to remember eight or nine out of 12 words instantly. But, if you can recall most of the list — nine or more — you’re performing above average, the expert states. Don’t fear, though: if only six to eight words come to mind, that’s still within the normal range. Mackenzie says that pressure and environment play a part in recall success here, so these things need to be considered (Picture: Getty Images)

Paying attention and switching gears

‘Healthy thirtysomethings can focus on a demanding task (like writing a report or analysing a spreadsheet) for at least 20 to 30 minutes without major lapses,’ Mackenzie states. She says that in tests that require switching between tasks or sorting things mentally, most people in this age bracket perform quickly and with only the occasional slip. However, the older we get, the more problematic task switching becomes. This is because it ‘slows down productivity due to the speed needed to attend to a new task’ (Picture: Getty Images)

Problem-solving and reasoning

‘Whether you’re solving a tricky work problem or planning a group trip, your ability to assess information and reach logical conclusions is typically operating at a high level,’ notes Mackenzie. For people who can solve simple brain teasers, logic puzzles or Sudoku with little frustration, Mackenzie says you’re ‘right where you should be for your age.’ But, the expert warns, these apps and puzzles only make you better at the puzzle, not necessarily at real-life tasks (Picture: Getty Images)

Ultimately, Mackenzie says, ‘if you find that you can recall seven random numbers, remember eight or nine items after hearing a word list twice, focus on a project for half an hour without constant distraction, and keep up with everyday problem solving, your brain is demonstrating the healthy “norms” seen in population data for people your age’ (Picture: Getty Images)

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