GOOD HEALTH
It’s a crippling sleep condition that blights the lives of millions. But as a major series by one of Britain’s top experts reveals, many don’t even know they’ve got it...
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Nothing is more guaranteed to sink the heart of the doctor opening a patient’s notes than seeing the acronym tAtt, which stands for ‘tired all the time’. For the list of possible causes of tAtt is almost endless: underactive thyroid gland, diabetes, depression, cancer, shift work, anaemia, carbon monoxide poisoning... the list goes on.
it is also incredibly common. Working out if there’s a serious underlying issue can be like looking for a needle in a haystack.
one possible — if under-considered — explanation is sleep apnoea. this is a sleep disorder in which someone briefly, but repeatedly, stops breathing during the night. Unsurprisingly, this disturbs sleep, although the person may not realise it — and over time, sleep apnoea has serious consequences for health, including an increased risk of stroke and heart disease.
in fact, we are living through a sleep apnoea epidemic. A recent Swiss study suggests that up to one in two men and one in four women has problems with their breathing at night. Maria was one of them. When i met Maria, a woman in her 40s who’d been referred to our sleep clinic, i imagined that tAtt has been scrawled in her medical notes by her gP.
Juggling motherhood and a challenging job in healthcare, she told me: ‘i was exhausted all the time. i never felt well and thought maybe it was my thyroid or anaemia. i went to the doctor repeatedly for blood tests.’
Sheer exhaustion was impacting on all aspects of her life. She had developed eczema — after a lifetime of clear skin — and was struggling to shift a little extra weight. exercising felt impossible.
it was also having a significant effect on her relationship with her husband. ‘Any little bump in the road was like the worst thing that had happened to anybody ever, and i’d fly off the handle,’ she explained. ‘i’m quite a cheery person by nature but my sense of humour went.’
Fuelled by coffee, Maria would pinch herself under the table in meetings to make sure she didn’t doze off. if she wasn’t working, she would take her children to school, then go back to bed, setting her alarm for 20 minutes before she had to pick them up again.
‘i didn’t even have the energy to read a book because i’d be asleep before i got to the end of the page,’ she told me. ‘i really did feel like i was falling apart.’
As i listened, i was struck by the lengths that Maria went to in an attempt to improve matters. ‘i was doing everything i could,’ she said. ‘i was trying meditation, yoga, mindfulness, i was trying to change my diet. i even changed my job.’
it was 18 months before sleep apnoea was considered. that’s when she was sent to our clinic at guy’s hospital.
normally, as you drift off, the countless small muscles of the walls of your airway slacken a little. however, if your airway is narrow enough or becomes sufficiently floppy, it can become partly or completely obstructed.
PATIENTS SIMPLY STOP BREATHING
thiS collapse results in oxygen levels falling and the heart rate increasing, disrupting your sleep in order for muscle tone to return briefly to the airway, allowing you to breathe again.
this can happen ten, 20 or even, in rare cases, 100 times an hour.
the rates of sleep apnoea have increased in parallel with our girths and neck circumferences. Fat around the neck makes the airway narrower and more likely to collapse, while fat on the chest increases the effort of breathing.
But obesity is not the only cause of sleep apnoea. it may run in families and is often related to the shape of the airway. A large tongue, recessed lower jaw and large tonsils can cause a narrowing, too.
it also appears to be more common in people of South-east Asian ancestry. it is more common, too, in older people, possibly because changes to muscle as we age mean the airway is more likely to collapse in on itself.
Snoring can be a warning sign, but it is not just a snoring problem. having your sleep disrupted several times an hour, results — unsurprisingly — in excessive sleepiness during the day.
this sleepiness can be extreme. At our centre, we’ve had countless patients whose sleep apnoea has come to light after they have fallen asleep at the wheel of their car and had an accident. indeed, having sleep apnoea increases the risk of a accident by two or three times.
DANGER MISSED BY DOCTORS
SLeeP apnoea has costs beyond tiredness. With each obstruction and brief suffocation, there is a surge of noradrenaline (a stimulating hormone), a rise in heart rate and blood pressure, a stiffening of the arteries and a drop in oxygen levels.
With each pause in breathing, changes to blood flow back to the heart result in altered levels of a hormone called AnP, which means the kidneys continue to produce more urine than they otherwise would at night. this results in more frequent nocturnal urination.
over time, these physiological changes can lead to permanently high blood pressure and, in turn, the serious problems it causes such as heart disease and stroke.
there is also a link with shortterm cognition problems, such as concentration, and possibly longterm with Alzheimer’s disease (see panel, far right).
While high blood pressure is one of the largest risk factors for cardiovascular disease and stroke, there seem to be additional effects of having sleep apnoea that may play a part. experimental research into recurrent drops in oxygen suggests that these fluctuations can cause the thin lining of the blood vessels to stop working as it should.
Known as the endothelium, this lining has an important function: it detects changes in blood flow and releases substances that regulate the size and thickness of blood vessels in response. Dysfunction of the lining is considered an early stage of cardiovascular disease.
Maria was only diagnosed with sleep apnoea by chance. She recalled it vividly: ‘i was at the doctor’s for something else, and an information video came on the screen in the waiting room describing some symptoms. i went in to see my gP and said: “i think i’ve got sleep apnoea.” ’
it was at this point she was referred to our centre. A piece of kit she was given to wear at home at night to monitor her breathing,
heart rate and oxygen levels then revealed that her oxygen levels were dipping an alarming 86 times every hour over the course of the whole night.
The tell-tale signs had been there. Maria was a snorer — loud enough for her husband regularly to seek sanctuary in their toddler’s bedroom. She had also been getting up three or four times a night to go to the loo.
She said: ‘Although doctors asked if I was sleeping OK — which technically I did, for as soon as my head hit the pillow I was out — they didn’t delve into me getting up frequently in the night, or anything like that.’
The problem may have been that Maria didn’t fit the traditional mould for sleep apnoea. She wasn’t elderly, she hadn’t got a particularly large neck and she wasn’t obese. Also, the problem is more common in men. Sleep physicians do, however, see people of normal weight who stop breathing an astounding number of times a night.
CAN A TONGUE ZAPPER HELP?
There are various treatments for sleep apnoea. Weight loss helps, and for some patients options include not sleeping on their back and oral devices to hold the lower jaw forward and open up the airway.
More recently, for very serious cases, an electronic device can be implanted in the neck to stimulate the nerve that retracts the tongue in sleep. At the time, however, there was really only one choice for Maria — CPAP, or continuous positive airway pressure. This device consists of a face mask attached to a small machine that pumps out pressurised air that keeps the airway open during sleep.
Benefits of CPAP on cognitive functioning, mood and sleepiness have clearly been demonstrated. We also know that CPAP results in an improvement in blood pressure and the function of the endothelium.
The research is less clear on whether it can reduce the risk of longer-term problems such as the risk of stroke or heart disease.
While many patients find it hard to stick with using the mask, Maria persisted.
No longer short-tempered and exhausted, Maria was smiley and energetic and she told me her sleepiness had totally resolved. ‘I don’t love the mask,’ she said. ‘But the effect it has had on my life has been so positive.
‘I used to come home, switch on the TV and be asleep within half an hour, but now I can focus.’