DR MICHAEL MOSLEY: Why too much sleep can drain your brain power...

DR MICHAEL MOSLEY: Why too much sleep can drain your brain power… and it could also raise your risk of a heart attack and stroke

Did you enjoy an extra hour in bed last Sunday when the clocks went back? We’ve been repeatedly warned about the dangers of not getting enough sleep so, understandably, most of us would have seized the opportunity to get more shut-eye.

But new research suggests that trying to pack in more sleep can actually undermine our health.

There is no question that a good night’s sleep benefits our brains. We feel groggy and irritable if we have slept badly, and long-term sleep deprivation can lead to serious damage.

It is when we are in deep sleep that our memories are preserved — and when channels open in our brains, allowing fluid to gush through and clear away any waste products that have built up during the day.

So, you might imagine that people getting the most sleep must have the healthiest brains. But a recent study, from Washington University Sleep Medicine Center in the U.S. concluded that for older adults, too much sleep may be as bad for their brains as too little.

New research suggests that trying to pack in more sleep can actually undermine our health, writes Dr Michael Mosley

The researchers looked at 100 adults, average age 75, who had been taking part in a long-term study of their brains, which included doing things like repeated memory tests.

They were also given portable EEGs (electroencephalographs) which measured their brain waves to provide an accurate picture of how much they were sleeping.

They couldn’t rely on the participants telling them this, as previous EEG studies have shown we actually sleep around an hour less each night than we think we do. So if you think you’re getting seven hours a night, you are probably only really having about six. That’s because we often wake up during the night but don’t remember doing so.

The researchers then compared how long the volunteers were sleeping with their mental performance over the five years of the study.

The best results were seen in those getting 4.5 to 6.5 hours of EEG-measured sleep each night, the equivalent of between 5.5 and 7.5 hours of self-reported sleep. People getting more, or less, than those amounts showed the biggest declines in brain power.

Fertility benefit of cleaner air

The tiny particles we inhale from polluted air cause chronic inflammation throughout our bodies, which not only damages our heart and lungs, but egg and sperm production as well

The talk at Cop 26 has been all about the impact on our climate and planet of burning fossil fuels.

I hate to add to the gloom, but it also has a more subtle and insidious effect — it can reduce fertility.

The tiny particles we inhale from polluted air cause chronic inflammation throughout our bodies, which not only damages our heart and lungs, but egg and sperm production as well.

A study published earlier this year in China found that 26 per cent of couples exposed to higher levels of air pollution were unable to conceive after a year of trying, compared to 15 per cent of couples breathing healthier air.

If you want to have kids, that is a big difference, and something to add to the long list of reasons why we should be switching to cleaner, greener fuels as soon as possible.

This fits in with other major studies, such as one published in the Journal of the American Heart Association in 2017, which compared people’s levels of self‑reported sleep with their risk of developing heart disease and dying. The people who said they slept significantly less, or more, than seven hours had a higher risk of having a heart attack or stroke than those around the seven hour mark (which is roughly the amount most Brits say they normally get, although the advice is to have eight hours).

As to why sleeping more than average is linked to poor health, this may be partly because people who are already in ill health spend more time in bed, so it’s not the long sleep that is causing the poor health, but the other way round. But the researchers from Washington University Sleep Medicine Center also suggest that spending more time in bed can be counterproductive because it leads to more fragmented, poor-quality sleep, which is bad for you.

In other words, if you really want to enjoy the full benefits of a good night’s sleep, you need quality rather than just quantity.

Ensuring you have more quality sleep might sound difficult, particularly if you are an insomniac (someone, for example, who wakes up a lot in the middle of the night and then struggles to get back to sleep, as I do). But one of the most simple, but effective, ways to achieve it is to restrict the hours you spend in bed. The trick with Sleep Restriction Therapy (SRT) is to teach your brain to associate ‘bed’ with ‘sleep’ and nothing else.

The idea is that for a short period of time you restrict your sleep by getting up at the same time every morning but going to bed later than normal.

So if you normally go to bed at 11pm and get up at 7am, then you might try going to bed at midnight, or even 1am, instead. This will increase your sleep drive, so the next night you will fall asleep faster and hopefully wake up less frequently. You do this for a week or two, until you have got back into the habit of falling asleep easily, then gradually increase the amount of time you spend in bed until you get enough quality sleep.

This will vary from person to person, but one of the best ways of telling if you are getting ‘enough’ is whether you feel sleepy and irritable during the day.

If you want to try SRT there are four things to bear in mind.

1. Do not cut your time in bed to less than five hours.

2. Stick to it rigorously.

3. Do not lie down, nap or snooze during the day.

4. Do not drive or use machinery if you experience serious daytime sleepiness.

There are more details about how to do SRT in my recent book, Fast Asleep.

Note: if you have serious insomnia then you might want to talk to your GP or get professional support from someone who is trained to deliver CBT-I (Cognitive Behavioural Therapy for insomnia).

Could next year’s Covid jab be given as a painless patch?

Some good news for people with trypanophobia — a fear of needles — who want to be protected against coronavirus.

When coated with the Covid vaccine they can be pressed onto your arm with a single click from a spring-loaded applicator.

This is not only painless but the vaccine doesn’t have to be stored at cold temperatures either. Also, when a vaccine is given this way the tiny needles puncture just the outer layer of the skin — this is called an intradermal injection and this can produce a much more powerful immune response than a vaccine delivered via a needle into muscle. That’s because your skin is packed full of immune cells, primed to respond powerfully to any foreign intruders.

Studies using flu vaccines have shown you only need to give a fifth of the normal dose to get the same effect as injecting into muscle. Despite these advantages, few vaccines are routinely administered with intradermal injections because you have to get the needle into just the right layer of skin (the dermis) and this normally requires trained medical staff.

But if a Covid vaccine could be given as a patch, it would be painless, which might encourage more vaccine refuseniks to come forward. It could be done without needing any expertise as the needles are designed to only reach the dermis. The patch could even be self-administered. This approach has only been tested on animals but trials on humans begin next year.

A team at The University of Queensland are testing a skin patch that they’re hoping to use to deliver Covid-19 vaccines. It consists of a strip of plastic, just 1 cm square, covered with 5,000 tiny plastic spikes. When coated with the Covid vaccine they can be pressed onto your arm with a single click from a spring-loaded applicator (stock image)

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