From 'banking' sleep to your brain's nightly 'wash cycle': Surprising ways to futureproof your mind at any age

“Brain health isn't something to think about solely later in life,” says longevity nutrition expert Melanie Murphy Richter, who works with L-Nutra. “Many drivers of cognitive decline are modifiable and the earlier we begin, the quicker we can protect and preserve our brain health.

“When we understand what the body needs at each stage, we can [improve] how well we think, feel, and function over time.”

To get the definitive blueprint on cognitive longevity, we sat down with Murphy Richter, neuroscientist, psychologist and co-founder of Muse (a mental fitness brand), Ariel Garten, and Claire Barnes, a registered nutritional therapist via Nutritionist Resource.

From the ‘youthful plasticity’ of brains in their twenties to the ‘glymphatic wash’ of the sixties, here is how to protect your most precious asset.

In your 20s

The goal: Build ‘neural reserve’ and hone critical thinking

In your twenties, the brain is in a unique state of “youthful plasticity”, explains Garten, meaning it’s an absorbent sponge, primed for learning new skills (and rewiring negative thought patterns is easier). “The prefrontal cortex, the part of the brain responsible for inhibition, strategic planning, and strategic decisions, is not fully developed until you are in your mid-twenties,” says Garten, and new University of Cambridge data suggests we may not even officially be deemed ‘adults’ (at least not in the eyes of science) until we reach 32 — with one of the five newly-identified core brain eras striking up around then.

Elsewhere, as your twenties is the decade of foundational wiring, Garten suggests that the most important habit to establish is critical thinking; in an era where we increasingly offload our decision-making to AI and get sucked into algorithms, she believes we’re at risk of letting our prefrontal cortex melt like butter.

“Can you take in a whole bunch of information, analyse it, have higher-order processing, and reorganise it? We need to exercise that skill to build a resilient brain,” she says Garten. By engaging in deep, analytical work, you will also create ‘neural reserve’ — a surplus of neural connections that act as a buffer against age-related decline later in life.

In practice, that could mean swapping 20 minutes of doomscrolling for something more mentally demanding: summarising a book chapter from memory, learning a language, debating ideas with friends or even tackling a difficult puzzle. The key is actively processing information, not just passively consuming it.

On the foodie front, given that your twenties are often defined by irregular schedules and convenience snacks, Murphy Richter warns it’s wise to keep track of blood sugar variability as it’s “one of the biggest drivers of brain fog, anxiety, and burnout in this age group”.

When glucose is constantly spiking and crashing due to caffeine and refined carbs, it directly impacts focus, mood, and energy. Establishing a habit of consistent, balanced meals with protein, fat, and fibre now sets the trajectory for how your brain will perform decades later, she advises.

In your 30s

The goal: Protect the hippocampus and master sleep

If the twenties are about building good habits, the thirties are about mitigating what can often be a high-stress decade. Careers are in full swing, some will have young families and “[this] chronic stress can lead to the production of cortisol and the inability to downregulate it,” cautions Garten.

Garten explains that chronic stress can create a harmful feedback loop in the brain: the amygdala — the region responsible for detecting threats — triggers the release of cortisol, the body’s main stress hormone. Over time, persistently high cortisol levels can keep the amygdala in an overactive state, while also affecting the hippocampus, the part of the brain involved in learning and memory. “The hippocampus is very sensitive to cortisol,” Garten says. “High cortisol has been shown to shrink its size.”

Your best defence here? Sleep. Garten cites research showing that sleep deprivation is also the primary predictor of anxiety the next day, which then makes us less able to emotionally self-regulate. However, the neuroscientist also notes that the brain is resilient, cheerfully detailing that you can actually ‘bank’ sleep — getting a few nights of high-quality rest increases your cognitive reserve and makes you less vulnerable to future stressful periods.

This is also a decade where environmental exposures start to accumulate, says Murphy Richter. “Everyday inputs, from ultra-processed foods to microplastics and endocrine-disrupting chemicals, can quietly influence inflammation, hormone balance, and long-term brain health [...] so the focus should not be on doing more, but on doing the right things consistently,” the dietician shares.

As for what to pile on your plate, Barnes recommends “meals that combine protein, fibre and healthy fats, for example eggs, Greek yoghurt, oats, lentils, beans, nuts, seeds, oily fish, grass-fed meat and plenty of vegetables”.

In your 40s

The goal: Neuroprotection amidst metabolic shifts

For women, the forties are often defined by perimenopause, marking not just a reproductive shift but a neurological one. Oestrogen and progesterone are both deeply neuroprotective (good for the brain, basically). “Progesterone breaks down into allopregnanolone, which interacts with your GABA receptors — which are the inhibitory, calming receptors in your brain,” Garten explains.

As these hormones begin to drop at pace, the brain loses its ‘calming bath’ of feel good hormones, leading to the hallmark symptoms of brain fog and having a shorter fuse. Garten notes that it is common for women to experience personality swings or “anger and irritability” because the brain is literally craving the calming influence of progesterone to function.

Garten says one of the most effective ways to support the brain during perimenopause is to focus on calming your nervous system. That could mean building in short daily meditation sessions, practising breathwork, prioritising sleep and making space for genuine downtime.

Metabolically, your forties are when insulin resistance can begin to surface more clearly. “There is a growing connection between metabolic dysfunction and brain health,” says Murphy Richter. Some researchers now refer to cognitive decline as a metabolic issue, as much as a neurological one.

Protecting the brain in this decade means focusing on anti-inflammatory nutrition, all experts agree: go heavy on Omega-3 fats and polyphenol-rich foods like berries and extra virgin olive oil.

In your 50s

The goal: Keep that brain plump and juicy

As we enter our fifties, the brain is confronted with a natural decline in volume, much in the way your muscles start to thin out too (joy of joys!). However, research into meditation shows promising impact.

Garten points to a study by neuroscientist Dr Eileen Luders, which looked at long-term meditators (defined as 5 years or more of practice). “People who were long-term meditators were able to maintain the volume of their prefrontal cortex even as they aged,” Garten reveals. “In her study, she had one subject in their fifties with the prefrontal cortex thickness of a 23-year-old. Globally, long-term meditators had brains that looked 7.5 years younger.”

It’s not just about doing your mental exercises though, physically working out does the world of good. “When you do resistance-based exercise, your muscles release myokines,” Garten explains. “These are signals that actually go up into your brain and trigger brain development.” While cardio improves blood flow and oxygen, resistance training has been shown to lead to better overall cognitive function in older adults.

Support this with food, advises Murphy Richter, and supplements if there’s anything your diet is lacking. “This is the decade where changes that were once subtle begin to feel more tangible. Energy may not be as consistent, recovery takes longer and cognitive changes, like forgetfulness or brain fog, can start to appear,” she shares. “Prioritising omega-3 fats, polyphenol-rich foods like berries and olive oil, and adequate protein to support muscle and metabolic health [should be the focus].

“It is less about restriction and more about protecting what supports the brain long term. Blood sugar stability, inflammation control, and muscle preservation all become central to maintaining cognitive function.”

In your 60s and beyond

The goal: Toxin clearance and delta wave optimization

Throughout our lives, the brain undergoes a fascinating biological process called glymphatic clearance — which Garten describes as being the brain’s trash-clearing system that kicks in when we sleep. “As you sleep, your neurons shrink slightly to make little channels between them, so that fluid can move through and literally wash out the brain's toxins and things that have built up,” she says. One of these toxins is beta-amyloid, the precursor protein for Alzheimer’s and in our sixties, it’s harder to come by.

Why? This “wash” is triggered by delta waves (slow-wave deep sleep) “and as you age, your delta waves decrease,” Garten warns. If the neurons aren't communicating effectively, you don't get the sum total activity of that big delta wave pumping the fluid. So, in practical terms, that means treating sleep less like a luxury and more like preventative healthcare — especially in later life.

Physiology also morphs in your sixties as nutrient absorption declines. Barnes notes that reduced stomach acid can lead to deficiencies in B12 and Magnesium, both essential for neurological health. “The gut and brain are in constant communication through the gut-brain axis, particularly via the vagus nerve," Barnes details. A diverse, fibre-rich diet is essential to keep the “information hub” of the gut sending “safe” and nourished signals to the brain.

Still, if there’s one thing Garten wants you to know, it’s that the brain is inherently resilient — at any age. “Brain health is built daily,” Garten concludes. “When we understand what the body needs at each stage, we can be proactive in protecting how well we think, feel, and function over time.”