DR MICHAEL MOSLEY: ‘Seeing’ a ghost is a wake-up call you can mute

Have you ever seen a ghost? Not me, but my wife, Clare, woke me up earlier this week, convinced there were ghosts in our bedroom.

“I see them moving at the foot of the bed,” she told me. “They don’t have faces and they don’t look threatening, but they’re definitely there.”

At that point she turned on the light and insisted we get out of bed and look behind the curtains and then under the bed. Reassured that the ghosts were gone, she went back to bed and quickly fell asleep.

In fact, I didn’t find this particularly strange as it happens quite often. I don’t believe in ghosts for a second, and neither does Clare, when she’s fully awake.

But what she’s been through isn’t a conventional nightmare, nor is it a sign that she’s losing her mind. Instead, it’s caused by something called sleep paralysis.

Experiencing sleep paralysis, with or without the ghosts, is surprisingly common.

According to the American Academy of Sleep Medicine, 20 percent of us experience this on a regular basis.

And while most people, like Clare, just think, “That’s weird,” and then go back to sleep, many find it genuinely terrifying.

So what’s going on? Sleep paralysis occurs during REM (Rapid Eye Movement) sleep, the period when we have our most intense dreams and nightmares.

While in REM sleep, our limbs become temporarily paralyzed to prevent us from thrashing around and hurting ourselves or others; you keep breathing and your eyes flicker back and forth, but you can’t move.

Most of us are completely unaware that this is happening because we are asleep, but sometimes your brain wakes you up while you are still in the throes of REM dreams, and that can be disturbing.

Different cultures have different explanations for these intensely vivid experiences.

For example, a 2015 study in Italy found that 38 percent of people who reported experiencing sleep paralysis believed a supernatural creature called Pandafeche — a feline creature — was to blame.

According to local folklore, the best way to prevent a Pandafeche attack is to have a pile of sand by the bed to throw in its eyes.

Brazilians, on the other hand, are more likely to blame sleep paralysis on a demon named Pisadeira, a witch-like creature with sharp fingernails that walks on people’s stomachs when they sleep on their backs.

At least there’s something to that myth because you’re much more likely to get sleep paralysis if you sleep on your back.

You’re also more likely to experience it if you’re a shift worker or suffer from post-traumatic stress disorder (both of which disrupt sleep) — or if you have a family history of sleep paralysis.

None of this applies to Clare’s case. Although it’s more likely to happen when she’s stressed, and there’s some suggestion that sleep paralysis could be stress related.

As for why people see ghosts or demons, Professor Baland Jalal, a neuroscientist at Harvard University, has a theory: He suggests that when you wake up and realize you’re paralyzed, your brain switches to the most obvious jump to conclusion – namely that there is a supernatural agent involved.

In a state of heightened alertness, your brain also interprets any shadowy shapes you can see as demons or ghostly creatures.

According to Professor Jalal, who suffers from sleep paralysis himself, the reason these demons are normally faceless is because creating a mental image of a shadowy creature requires far less brain power than creating something distinctive.

And when you’re still halfway through REM sleep and full wakefulness, your brain is much more concerned with getting you out of harm’s way than paying close attention to what this mysterious shadowy threat really looks like.

So what can you do?

If you have frequent ghost visits, avoid eating a large meal or drinking alcohol a few hours before going to bed, as these will interfere with sleep.

You can also reduce the chances of sleeping on your back by sewing a tennis ball into your pajamas, or by wearing a device around your neck that senses when you’re lying on your back and gives you a small jolt to force you out of position to change.

If it’s more serious, you may want to consider cognitive behavioral therapy – this aims to change patterns of behavior and replace negative thinking with more positive ideas.

This was the basis of a study led by Professor Jalal, in which patients who said they often suffered from disruptive sleep paralysis were asked to practice three simple things.

They were first asked to remind themselves, when well awake, that what they had experienced is normal, benign and temporary – and that these kinds of hallucinations are a typical by-product of dreams.

Second, they were asked not to focus on feelings of fear, but to focus on positive feelings, such as thinking about a loved one or a short prayer to God.

And finally, they practiced muscle relaxation exercises, where each set of muscles could be relaxed one at a time for 15 minutes a day, for two days a week.

Impressively, after eight weeks, the patients experienced a dramatic reduction in the number and severity of their attacks, as reported in the journal Frontiers in Neurology in 2020.

Professor Jalal says if larger studies support these findings, this kind of treatment could be delivered to patients through a smartphone app.

I look forward to that. In the meantime, I’ll keep making fun of Clare when she jumps out of bed and goes looking for ghosts.

People with type 2 diabetes who exercised in the afternoon had greater reductions in their blood sugar than those who exercised in the morning, according to a recent study published in the journal Diabetes Care.

They were also more likely to get off their diabetes medications.

While it’s not clear why there’s a difference, it seems like a simple tweak with real impact.

If you’re a mouth breather, you might want to do something about it: As I found out while researching for my latest Just One Thing podcast series, mouth breathing can be bad news for your teeth.

This is because it reduces saliva production, which is essential to get rid of harmful bacteria in your mouth. Mouth breathers are more likely to cause fillings and sore gums.

Plus, it changes the way facial muscles move and the forces they exert on your jaw: If a child breathes through their mouth, it can change the shape of their face.

Nasal breathing, on the other hand, has health benefits. For example, the hairs in your nose act as a filter, removing dust, pollen, and other particles.

The nose itself helps warm and humidify the air, which improves oxygen uptake in your lungs.

And nasal breathing causes the release of nitric oxide gas in your sinuses, which kills bacteria.

When the nitric oxide reaches your lungs, your blood vessels expand, re-stimulating oxygen uptake.

Nasal breathing can also affect how well we record memories. In a 2018 study from the Karolinska Institute in Sweden, volunteers were asked to inhale 12 scents and then breathe through their nose or mouth for an hour.

In a later test, the nasal breathers were better at remembering the smells (scans show that nasal breathing during a memory test activates the brain more).

Some people breathe through their mouth due to sinusitis, adenoids or hay fever, which require treatment. But if it’s just a habit, yoga can help – where you learn to breathe through your nose.