Professor Russell Foster. — Photo thedoctorskitchen.com

Russell Foster is a British professor of Circadian Neuroscience, director of the Sleep and Circadian Neuroscience Institute (SCNi), and head of the Nuffield Laboratory of Ophthalmology at the University of Oxford. An acclaimed scientist, Foster has been elected to the Royal Society.

In his latest book, Life Time: The New Science of the Body Clock, and How It Can Revolutionize Your Sleep and Health, Foster shares his life's work, unpacks the science of the body clock and provides guidance on how to improve our overall health and being. He talks with Việt Nam News about the significant role of sleep and suggestions for a good one.

What is the importance of sleep?

What we've understood in the past 15 years is that during sleep, we consolidate our memories and also the processing of information. If you want to come up with a clever solution to a complex problem, actually sleeping on it helps you do that. We now know that whilst we sleep, important toxins are cleared from the body.

So there's the Amyloid β-protein (Aβ), which is associated with Alzheimer's, being cleared and got rid of whilst we sleep. And there's now strong evidence that if we have massively disrupted sleep during the middle years, there's an increased risk of dementia in later years.

We also need to rebuild our metabolic pathways and essentially, the quality of our day whilst we're awake is defined by the quality of our sleep at night.

Do people from different cultures have different sleeping patterns?

There are huge differences in sleep patterns. A better way of putting that would be: "One shoe size doesn't fit all". In fact, part of the reason for writing Life Time was I was very irritated by the widespread social pressure to get the eight-hour sleep and this is causing anxiety.

There's a huge range in sleep duration. Some people are perfectly happy with six hours while some others might need ten to 11 hours of sleep. And the key thing is to identify how much sleep we need and then get the pattern of sleep that works best for us.

So there are major differences among individuals and our sleep patterns can be much influenced by culture, but there's nothing that is distinctive about one particular nation against another. In fact, it's rather lovely because sleep is perhaps one of the things that unites people across the world and it is also a really important part of what makes who we are.

Can COVID-19 cause sleeping problems?

This is a really important point – the difference between sleepiness and fatigue. Now sleepiness can be cured by getting a good night of sleep, but fatigue is the overwhelming sense of tiredness, lethargy, inertia, lack of energy and also the result of an underlying illness of some sort.

And of course, this is what many people have experienced as a result of COVID. Basically, no matter if they're sleeping longer or at least they're staying in bed longer than they normally would, they're still feeling this overwhelming sense of fatigue.

My wife, for example. It took her two months to recover from the fatigue of COVID. She was sleeping longer, but she was still feeling exhausted. She's fine now. It's basically for the body to realign itself, get its immune system back on track and get rid of all of the incredible insult that COVID has inflicted on so many individuals.

What are some tips for getting a good sleep?

If you nap, make sure it's not longer than 20 minutes and not too close to bedtime.

Exercise is very good but try to do it in the morning, not too close to bedtime as well. One of the processes in getting to sleep is a drop in core body temperature. By exercising, you raise your core body temperature and it's more difficult to get to sleep.

When you eat is really important. Over the past hundreds of years, we've shifted our eating patterns. Many of us will not have breakfast or lunch but we'll have a big evening meal. Because of the circadian system, we are much more likely to turn that evening food into fat than burning it up during the day. If we increase our body mass index, we are much more vulnerable to conditions such as obstructive sleep apnea.

Before bed, reduce light levels 30 minutes or so before. The greater the light, the greater the alertness and the more that would delay sleep on set. Again, stop using electronic devices because they're gonna have an alerting effect.

The key things to remember is that sleeping tablets are sedatives. They do not provide a biological mimic for sleep. The process of information is all impaired by some of these sedatives and they can cause daytime sleepiness and therefore you can't function optimally. Many people might also use alcohol to sedate themselves to sleep, but again, it's not proper sleep and it can lead to disrupted sleep.

Before bed, avoid the discussion of stressful topics like family finances.

A relaxing bath or a shower can be useful. The bedroom itself shouldn't be too warm and should be quiet. If it isn't, try to use white noise or something else dark like curtains.

Don't take sleep apps seriously. So many people are now using devices which tell you've had wonderful or awful sleep. They actually don't work for most people and can generate huge anxiety.

Keep a routine to go to bed and get up at the same time on free days and work days.

Ensure the bed is a good one as around 30 per cent of our lives are spent on it. Try defining the sleeping space with a particular smell, whether it is lavender oil or some other smells. That means you are going into that place and associating the smell with sleep. It can be useful if you do a lot of travelling.

Finally, if your partner snores and you can't deal with earplugs, find an alternative sleeping place. It is not a reflection of the quality of your relationship. — VNS