The key to being happier, smarter and ageing better, by leading neuroscientist DR JOSEPH JEBELLI. An extraordinary scientfic breakthrough shows what part of modern life is destroying our brains - now his new book has the cure

You’re sitting at your desk, trying to look busy, and your work isn’t going well. OK, it’s time to double down and try a bit harder... but for some reason your brain fails to ignite.

It’s just one of those things we all experience at work – and until recently, no one really understood how to kick-start the brain back into action.

As a neuroscientist, however, I can tell you exactly what will help. Next time your concentration falters, just try staring blankly into space for up to 20 minutes. Let your thoughts drift – maybe to a good friend, to a holiday you once had, to a delicious meal. Anything but work.

You may think you’re doing nothing, but you’re actually allowing your brain to enhance your intelligence and creativity.

At the same time, you’re reducing your chances of developing neurological illnesses, including depression and dementia. Not bad for a little day-dreaming!

What I’m about to tell you is a recent scientific discovery – and it’s quite extraordinary.

The key to success (and good brain health) is regular periods of doing nothing very much at all. That includes staring through the office window. It means slipping outside during the working day, sitting on a bench and simply watching the world go by. Or curling up on the office sofa for a 30-minute snooze.

I know this sounds like an indulgent, unprincipled, even irresponsible way of behaving, but the science behind it is sound. Doing nothing – or at least having several daily periods of non-work-related activity – has truly profound benefits for your brain.

By following my tips, you’ll not only be mentally and physically healthier but you’ll also work less and achieve more.

So what’s going on? In 2001, scientists made a major discovery: when you disengage, your brain activates a network vital for mental and physical health. We call this the default network, a circuit of neurons that enables us to daydream, reflect and imagine the future.

It spans the brain’s frontal, parietal and temporal lobes. This network is only active when we’re not focused on tasks – when our minds roam free. Activating it boosts intelligence, creativity, empathy and long-term productivity. It’s your brain’s hidden superpower.

You can better appreciate this by comparing it to the opposite – the executive network, responsible for focused, goal-oriented tasks. If the default network is for rest, the executive network is for work.

The executive network kicks in when we focus on chores, spreadsheets or emails. But when it’s engaged, the default network is subdued. When we rest, daydream or play, the executive network quietens down – and the default network lights up.

The groundwork for this was laid in the early 20th century by French polymath Henri Poincare. Frustrated by equations, he’d leave his desk and let his mind wander.

Solutions would suddenly pop into his head. Was there, he wondered, a kind of unconscious processing going on in his brain? Yes. His default network was hard at work while he appeared to do nothing – but it’s taken hundreds of scientific studies over the past 20 years to prove it.

The more time you spend doing nothing, the better it is for your brain. Taking time out isn’t a luxury – it’s a necessity.

That’s when clarity emerges and problems get solved. Unfortunately, in today’s world, we’re ignoring the default network, and that’s a catastrophe.

Society’s obsession with productivity fuels burnout, anxiety and stress-related disorders. Take doctors. In a recent study, 38 per cent described themselves as burnt out or depressed. More than half of healthcare workers report stress, fatigue and heart disease.

Or consider a teacher juggling family, students, chores and lesson plans. Her executive network is constantly on – until she finally collapses into bed.

Overworked brains span all professions. Every job now exerts relentless pressure on the executive network. But overwork destroys productivity. Without downtime, employees lose core job skills – planning, judgment, problem-solving and critical thinking.

The domino effect on the wider economy is profound: lower engagement, more workplace errors and accidents, increased staff turnover and, ultimately, decreased long-term productivity.

Put simply, our obsession with busyness destroys the brain’s ability to handle being busy.

I’m not saying abandon your ambitions. Far from it. Instead, I want to show you how to engage your brain’s default network which, paradoxically, will help you to flourish.

I know what you’re thinking: I don’t have time for this, I’m too busy! But many tasks – such as immediately replying to emails – aren’t mandatory.

The crucial point is this: the reason we sometimes feel overwhelmed is because we haven’t been mind-wandering enough. We haven’t been using our default network as nature intended.

If we did, we’d be less stressed, less anxious, more creative and more efficient. We’d get more done. So try to spend at least

20 minutes a day staring blankly into space. Let your mind wander, breathing slowly and deeply through your nose as you do. Even brief diversions from a task can dramatically improve your ability to focus on that task.

Try to take regular, scheduled mini-breaks throughout the day. Or you can mind-wander while knitting, stroking your cat, popping bubble-wrap – whatever doesn’t require a strong focus.

Try listening to sad music. Not only does it improve your mood when you’re feeling down (yes, really), but it’s also associated with stronger mind-wandering and greater default network activity. Scrolling through your phone or binge-watching a TV series won’t work, however; both these activities will fire up your executive network.

Researchers have spent decades trying to understand the biology of mind-wandering. Then in 2020, scientists found an important clue.

Inside the hippocampus, a subsystem of the default network that controls learning and memory, lie millions of tiny electrical signals called sharp wave-ripples. These pulse with each new episode of mind-wandering and activate billions of neurons throughout the default network.

Silence has extraordinary power to change the brain. It stimulates the growth of new brain cells and triggers the release of valuable proteins, such as BDNF (brain-derived neurotrophic factor), a molecule that helps slow the progression of Alzheimer’s disease.

It also leads to enhanced memory and attention, reduces stress and fosters emotional well-being.

What about the opposite of silence? Well, persistent noise changes our brains, too. It hinders the production of new brain cells and triggers the release of stress hormones. Of course, it’s hard to block out all noise, but the good news is that you’ll boost your default network just by swapping urban sounds for natural ones.

In 2017, scientists at Brighton and Sussex Medical School showed that people perform far better with cognitive tasks when listening to sounds in nature, because their default network is more active.

When we’re alone and not engaged in a specific task, we’re usually not consciously directing our thoughts towards any particular goal or outcome.

When my Catholic mother prays, for instance, she’s not expecting a response from a supernatural entity (at least I hope she’s not). In scientific terms, she’s accessing her default network to cultivate a state of internal harmony and peace.

Prayer activates vast swathes of the default network. As for meditation, we know it sends electrochemical signals through the brain’s elaborate maze of neural pathways within this network, ultimately enhancing our mental health and cognitive functions.

One night of poor sleep can make us more susceptible to infectious diseases including influenza, hepatitis and Covid (even when fully vaccinated). Just a few days of sleep deprivation can also cause almost immediate weight gain.

Sleep is your brain’s master healer. If you’re not getting enough of it, the neurons responsible for a variety of functions start to falter. Your cognitive agility diminishes, and concentration and problem-solving take a hit.

Whenever you’re asleep, a few critical parts of your neural network flicker into life. These include the regions that govern creativity and dreams – which are now thought to be the brain’s way of processing complex emotions – and working memory.

Conventional wisdom is that we need six to eight hours of sleep, but often that’s not enough. To nurture your default network, aim for eight to ten hours.

And the brain-enhancing properties of sleep aren’t limited to the night. In 2023, scientists found that people who take daytime naps literally have bigger brains than those who power through the day. So how much napping is enough to make us sharper and more alert? Scientists recommend no more than half an hour – every single day.

Remember spontaneous, joyful, carefree play – the kind you did as a child? You won’t be surprised to learn that this activates your default network. But so do all types of play.

A study of more than 2,200 children found those who played video games did better on memory tests than non-gamers. Still, balance is key. Experts suggest a maximum of 1-2 hours of video-gaming a day.

Gaming leads to significant changes in areas governing attention, spatial navigation and problem-solving. It enhances cognitive abilities and may even offset the impact of ageing on the brain.

Playing video games also enlarges grey matter in areas responsible for spatial navigation, memory formation, strategic planning and fine motor skills. And these changes have a lasting impact. They improve the brain’s ability to fend off disease, including Alzheimer’s and strokes.

Of course, gaming isn’t the only type of play that enhances brain health. So does any ball game. So does climbing a tree or playing tag or making pottery.

And so does collecting – whether it’s books, stamps or vinyl records – by improving your organisational thinking, enhancing your pattern recognition abilities, stimulating your creativity and helping you relax.

Periods of play don’t have to be prolonged. Dancing to a favourite song as you make dinner or singing as you cycle home will significantly improve brain health.

Rest can be an active process that involves stepping away from focused tasks. It can involve swimming, yoga, tennis, running – whatever floats your boat.

Studies have shown that not moving enough triggers anxiety, depression and heightened inflammation. Eventually, the brain’s neuroplasticity, its ability to adapt and grow, takes a hit. One amazing study measured the brainwaves of karate champions versus people from the general population, comparing them while at rest. Remarkably, despite being more physically active, the karate champions have more restful brains – precisely because their physical activity is ‘active rest’.

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It turns out that athletes, through years of physical training and mental conditioning, have repeatedly engaged their default network, strengthening it just as they’ve strengthened their bodies.

But these benefits aren’t exclusive to athletes. Taking up any new physical activity can lead to significant changes. After just a week of learning to juggle, for example, people develop extra grey matter in the default network, and these improvements can last for several months.

Improved fitness also triggers a neural detoxification process, removing metabolic waste products that can clog neural pathways and disrupt the function of the default network – a deep cleanse for your mind.

And you need only 25 minutes of exercise a week, less than four minutes a day, to grow a bigger brain. That’s what a large American study confirmed in 2024. Even better, it’s gentle exercise that does the trick.

Why does growing a bigger brain matter? Scientists now think it’s the most important thing we can do as we age. A recent Australian study showed that increased muscle strength improves brain function in people aged between 55 and 86 who have mild cognitive impairment (MCI), a condition in which people start to experience problems with their memory.

So how does mere exercise manage to do this? We now think that it raises the levels of BDNF (brain-derived neurotrophic factor), which acts like fertiliser on a garden, spawning new connections and strengthening existing ones within the default network.

To radically improve your health, try spending 20 minutes a day in a natural environment – whether that’s a park, garden, field or wood.

One of the best ways to activate your default network is forest bathing, an ancient Japanese practice that involves letting sights, sounds and smells wash over your senses as you stroll.

American researchers discovered that spending time in a forest improves creativity and problem-solving ability by 50 per cent.

Other scientists have shown that nature stimulates areas of the default network linked to memory (which is why you may feel a tug of nostalgia as you walk through greenery). Indeed, people who wander through woods can recall 20 per cent more information compared with people walking down urban streets.

It can also be a powerful remedy for depression, altering the activity of a brain region associated with depressive thoughts.

Perhaps most exciting of all, walking in woodlands raises the number of killer cells in the body by an astonishing 40 per cent. These are the white blood cells that can protect us from cancer and infections.

What’s more, even a week after volunteers walked through a forest, their natural killer cell count was still up by 40 per cent. Only after 30 days did it dip – but it was still 15 per cent higher than before the experiment.

How is this possible? In one experiment, scientists mixed the natural oils that protect trees – which we can smell during woodland walks – with human natural killer cells in a lab dish.

A few days later, the anti-cancer proteins had increased.

Researchers have also discovered a microbe, called Mycobacterium vaccae, that lives in the soil. Breathing this in as we walk literally makes us happier, by triggering the feel-good hormones serotonin and oxytocin, which modulate neuronal activity in the default network.

Last but not least, here’s a particularly enjoyable way in which to incorporate ‘active rest’ into our lives: sex.

Recently, scientists have found it has incredible effects on brain health – particularly if you are female, it seems.

In men, having sex appears to stimulate brain regions linked to bodily sensations and emotion, but in women it also engages parts of the default network that govern problem-solving, decision-making, complex emotion and introspection.

On the plus side for men, frequent sex appears to have cognitive benefits. When male rats have sex every day for two weeks, for example, they grow more brain cells than rats allowed to have sex only once a fortnight.

What if you have sex only once every few weeks? Not a problem. Whether you’re a man or a woman, it’s been shown to improve memory and thinking ability.

• Adapted from The Brain At Rest by Joseph Jebelli (Torva, £20), to be published June 19. © Joseph Jebelli 2025. To order a copy for £18 (offer valid to 28/06/25; UK P&P free on orders over £25) go to mailshop.co.uk/books or call 020 3176 2937.