DR MICHAEL MOSLEY: My tips for a good night’s sleep to head off dementia

One of my regrets in life is that I can’t really speak another language fluently.

I am ashamed of my basic French, but not enough to work hard to improve it. So I was thrilled when I came across a recent study that suggested you can learn new words in your sleep.

Researchers at the University of Bern in Switzerland played volunteers a series of words in a language they didn’t understand, along with a translation, while they were fast asleep.

Then, 36 hours later, they were asked to guess whether a particular word meant an animal, a tool, or a place. They fared significantly better than a control group, which didn’t play the words—amazingly proving that, despite sleeping soundly, they were still aware enough to learn something new.

That’s the good news. The bad news is that to achieve this effect, the researchers had to use very short words at just the right time in the volunteers’ sleep cycles, so unfortunately I’m not sure if this will help me.

But this study does confirm how much is happening in our brains while we sleep.

And it adds to the mounting evidence that deep sleep plays a vital role in memory and may even protect us from Alzheimer’s disease.

Deep sleep is one of the four main stages of our sleep cycle. It’s also called slow-wave sleep because millions of neurons in your brain then start firing together, producing large waves that slowly travel through your brain.

Deep sleep is when you’re most relaxed and hard to wake up, but there’s plenty going on beneath the surface.

Your pituitary gland in the brain begins to secrete more growth hormone, essential for cell growth and repair, for example.

Deep sleep also increases the production of cytokines, a type of protein essential for fighting infection. This is partly why a lack of deep sleep makes you more vulnerable to the common cold and also reduces the effectiveness of vaccines against infections such as the flu.

And deep sleep is when a network of channels in your brain known as the glymphatic system opens up, allowing fluid to flow through and flush out the toxic waste built up during the day. Which in turn can protect us against the consequences of diseases such as Alzheimer’s disease.

This was shown in a fascinating new study from the University of California (UC), Berkeley, where researchers measured the brain activity of healthy adults in their 70s while they slept. The study participants also had brain scans to measure levels of amyloid, a protein linked to memory loss and dementia.

The results showed that despite having high amounts of amyloid in their brains, the participants who got a lot of deep sleep did much better on memory tests than those who had less.

The researchers believe that deep sleep may help explain why some people, despite having their brains clogged with amyloid, continue to thrive into old age, while others develop signs of dementia.

As Matthew Walker, a professor of neuroscience at UC Berkeley and a leading sleep expert, explained, “Think of deep sleep almost as a life raft that props up your memory, rather than the memory being dragged down by the weight of Alzheimer’s disease. .’

Adults typically get about one to two hours of deep sleep per night, but this decreases as we age.

So how can we boost it? Aside from obvious things like cutting back on booze and going to bed fairly early (usually most deep sleep occurs in the first half of the night, which may lend modern credence to the old adage, every hour of sleep before midnight is worth two after), you could try cutting back on junk food and sticking to a higher fiber, Mediterranean diet instead.

Numerous studies have shown that people who follow a Mediterranean diet (a diet rich in nuts, olive oil, oily fish and vegetables) have better sleep quality, while those who eat junk food tend to struggle. This includes research recently published in the journal Obesity that compared the effect on sleep of a healthy diet versus a diet containing moderately high levels of ultra-processed foods.

The researchers at Uppsala University in Sweden randomly assigned a group of healthy young men to one approach for a week, then switched.

While the young men slept the same amount of time on both diets, they had shallower, less restorative deep sleep when they ate junk food, something that would become increasingly important as we age.

Surprisingly, listening to sound can also make a difference. A few years ago I tried out a headband that measures your brain activity during sleep. Once the headband detects you’re in deep sleep, it makes a clicking noise that’s so quiet it won’t wake you up.

For reasons unknown, this clicking sound, delivered at just the right time, helps amplify those low, slow waves you get in deep sleep.

Unfortunately, it did nothing for me, but a study published last year by the University Hospital Zurich produced more positive results.

It tested a similar device on a range of people between the ages of 60 and 80, and found it helped some get more deep sleep (although others, like me, responded minimally or not at all).

The researchers are currently trying to improve its effectiveness before releasing a commercial version.

But by far the simplest thing you can do, especially as we approach the longest day of the year, is wearing an eye mask.

Even with thick curtains, you will be exposed to a lot of bright light early in the morning and late at night, which will almost certainly disturb your sleep.

Wearing a mask works for me.

Does your face look older than your inner arm?

There’s a lot I love about this time of year, but the downsides include wasps, mozzies at dusk, and worst of all, ultraviolet (UV) light.

I recently finished making a TV series about aging, and one of the most striking things I’ve learned is how much the sun ages our skin, with up to 80 percent of facial aging being due to damage by UV light.

To see what your face would have looked like if you hadn’t had too much UV light, take a look at the parts of your body that don’t get much sun exposure, such as the inside of your upper arm.

Of course, prevention is better than cure: you can check the strength of the sun in your area with the UV index (search online) — it runs from 1 to 11, but even in the range of 3-5 you can still burn .

Once the damage is done, the creams with the best research behind them contain retinol, a compound that has been shown to reduce the appearance of wrinkles by increasing the elasticity and thickness of your skin. But retinol can cause skin irritation, so start with a low concentration (0.1 percent).

No one wants to get wrinkly ahead of their time, but developing skin cancer is even worse. While melanoma is the most feared, other forms of skin cancer, such as basal cell carcinomas (BCCs), are much more common and BCC cases have increased by 40 percent in the past decade.

My wife, Clare, is one of them: she is now in her early sixties and has recently had two removed from her face.

Although BCCs appear later in life, the damage is normally done at a much younger age. A sobering study from the University of Arizona, soon to be published in the journal Cancer Epidemiology, found that sunburn once every two years, at any time, nearly doubles the risk of BCC. So keep an eye on that UV index.

A few years ago, I became a living exhibit at London’s Science Museum when I swallowed a tiny camera and projected the pictures onto a giant screen. Visitors to the museum could see live images from my abdomen.

It was fantastically interesting, especially when I ate and we could watch the food arrive in my stomach and be digested slowly.

I then thought how much better it would be if I could maneuver the camera for the best images. And now researchers at George Washington University in the US have done just that, using magnets controlled by a video game-style joystick.

I look forward to taking it for a test drive.

Tomorrow is Father’s Day and there is still time to buy a ticket or call to tell your dad how much you love him. Sadly mine passed away 20 years ago but I miss him dearly. And now that I’m a father myself, I can appreciate everything he’s done for me. He passed away at the age of 74 from complications including type 2 diabetes. One of my greatest sorrows is that I was unable to give him the advice and support that might have kept him in good health for longer. So if your parents are still alive, cherish them.