In the wake of the pandemic, millions report difficulty sleeping. For the past three days, we have been sharing advice from consulting neurologist and sleep specialist Professor Guy Leschziner. Insomnia is generally not a threat to physical health.
But the same cannot be said about sleep apnea. In the last part of our series, Professor Leschziner focuses on identifying and managing the condition ...
Feeling tired all the time is a common problem - and the list of possible causes is endless: an underactive thyroid gland, diabetes, depression, cancer, shift work, anemia, carbon monoxide poisoning ... the list goes on.
One possible - if under-considered - explanation is sleep apnea. When you sleep, it is natural that the muscles in the walls of the neck relax a little.
However, in some people, this slackening causes the airways to collapse and block, causing you to snore loudly, repeatedly stop breathing, and then gasp awake or almost awake many times a night.
You probably will not realize that you are doing it - even if your partner may - and the danger is that these many small awakenings have an effect throughout your body.
Feeling tired all the time is a common problem - and the list of possible causes is endless: an underactive thyroid gland, diabetes, depression, cancer, shift work, anemia, carbon monoxide poisoning ... the list goes on
One of the major risk factors for sleep apnea is being overweight (especially if you carry fat around your neck). Other signs include snoring and multiple night trips to the toilet, as hormonal changes caused by each breathing pause encourage the kidneys to produce more urine than they would normally do at night.
An immediate effect of sleep apnea is significant sleepiness during the day, sometimes so severe that it leaves people at risk of falling asleep when they relax, or even behind the wheel of a car: sleep apnea increases the risk of a car accident with two to three times.
This fatigue does not make sense as you think you slept all night but you actually got disturbed your sleep several times an hour.
And with each obstruction and short-term suffocation, there is an increase in the activity of your sympathetic nervous system (the part of the nervous system that drives the fear-flight-fight reaction), an increase in heart rate and blood pressure, a stiffening of the arteries and a decrease in oxygen levels .
Over time, these physiological changes can lead to permanent high blood pressure and in turn the serious problems it causes such as heart disease and stroke.
There is also an association with short-term cognition problems, such as concentration the next day.
But there can also be a long-term risk to the brain, to memory loss or even worse, possibly Alzheimer's. And although we know that sleep apnea is strongly linked to obesity, the condition itself can encourage you to put on weight. For example, we know that sleep apnea also affects the levels of two hormones, leptin and ghrelin, which are important for regulating appetite and metabolism.
You probably will not realize that you are doing it - even if your partner may - and the danger is that these many small awakenings have an effect on your whole body, writes Professor Guy Leschziner
Separately, it has also been shown that the temporary drops in oxygen levels and sleep disorders reduce the body's response to insulin, the hormone that absorbs sugar from the bloodstream for storage in the cells - this can lead to insulin resistance, the first step in the development of diabetes.
So it may be that sleep apnea in itself increases calorie intake and how those calories are processed, leading to further weight gain.
Fortunately, once the condition has been diagnosed, there are very effective treatments for it. Weight loss helps, and other more immediate practical steps include not sleeping on your back and oral devices to keep your lower jaw forward and open your airways.
The main treatment is with CPAP, or continuous positive airway pressure. It consists of a face mask attached to a small machine that pumps out compressed air, which keeps the airways open at night during sleep. CPAP has been shown to improve cognitive function, mood and sleepiness as well as blood pressure (whether it reduces the risk of long-term problems such as the risk of stroke or heart disease is not yet clear).
Recently, patients with severe sleep apnea have been able to get an electronic device implanted in the neck to stimulate the nerve that pulls the tongue back to sleep.
PS. So how much sleep do you need?
One of the questions I am so often asked is 'how much sleep is enough?'. I have kept writing about this until the last part of my series because, as you will have seen over the last three days, the answer is: whatever is enough to make you feel fresh it next day. And that's what the practical steps, including CBTi, the therapy I explained in Sunday's newspaper, are about - not aiming for a certain number of hours of sleep.
Of course, seven to eight hours is the wisdom received - but this is the average - and who would say you are average?
There are plenty of outliers - a few people can thrive on five hours a night, while others still struggle with closer to nine hours of uninterrupted sleep.
Not only that, but as we pass through life, our need for sleep changes. A baby will sleep for two-thirds of the day, but in adulthood we tend to sleep between six and a half and eight and a half hours a night (again, this is only average).
And the sleep itself has several stages, which we repeat in about 90 minute cycles, four or five times during the night. As we slip away, we enter phase 1 'drowsy' sleep, then phase 2, known as light sleep, when brain activity decreases further, but we can still easily be pushed awake.
Step 3 is deep sleep and we usually go in after 30 minutes or so. In this phase, our brain waves are significantly slowed down, and this is where the body performs repairs, and the brain is thought to perform most of its 'clearing' of waste products.
The last phase that we usually go into after about 60 to 75 minutes is rapid eye movement (REM) sleep.
Here the brain waves look very active - a bit like when we are awake - and that is when we tend to dream. As adults, we enjoy deeper sleep in the first half of the night and most of the REM sleep in the second.
As babies, we spend about half of our sleep in REM sleep, while in adults it is 15 to 25 percent, and gradually decreases as we approach old age.
The proportion of deep sleep also changes, being around 15 to 25 percent in adulthood, but decreases slightly in the elderly, usually replaced by stage 1 and 2 sleep.
With all that said, the right amount of sleep for you, no matter how long it takes for you to wake up in the morning and feel fresh, without relying on an alarm, does not feel sleepy during the day or as if you need to 'catch up' to sleep on weekends or holidays, and feel ready to go to bed at a set time - with no trouble getting out.
Professor Guy Leschziner's new book, The Man Who Tasted Words: A Neurologist Explores the Strange And Startling World Of Our Senses, will be released on February 3 (Simon & Schuster, £ 16.99). See next week's Good Health for an exclusive extract.
Take this quiz to find out
If you are inexplicably tired, it may be a sign of sleep apnea (see main article). To find out more, answer these questions and then check your results.
1. Do you snore loudly (loud enough to be heard through closed doors, or if your bed partner elbows you for snoring at night)? Yes No
2. Do you often feel tired, tired or sleepy during the day (such as falling asleep while driving or talking to someone)? Yes No
Has anyone observed that you stop breathing or suffocate / gasp during your sleep? Yes No
4. Do you have or are you being treated for high blood pressure? Yes No
5. Is your body mass index (BMI) more than 35? (Calculate this by dividing your weight in kilograms by your height in meters squared.) YES / NO
6. Are you older than 50? Yes No
7. Is your collar size 16in / 40cm or larger? Yes No
8 Are you a man? Yes No
Add the number of 'yes' answers together. If you answered 'yes' to 0-2 questions, you probably have a low risk of sleep apnea.
If you answered 'yes' to 3-4 questions, you probably have a moderate risk of sleep apnea.
If you answered "yes" to 5-8 questions overall - or if you answered "yes" to two or more of the questions numbered 1-4 and "yes" to one of questions 5-8, you are probably at high risk for sleep apnea .
Adapted from the Stop-Bang questionnaire developed by Dr. F. Chung, of Toronto Western Hospital, University Health Network, Canada.
This is not a diagnostic test. If you think you may have sleep apnea, consult your doctor.