Results from a long-term study of 8,001 people suggest that disrupted sleep is linked to cardiovascular disease and mortality — in women more than men.
Women appear to experience worse long-term cardiovascular illnesses than man as a result of disrupted sleepImage: Colourbox/S.Mironov
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We all wake occasionally during the night. We hear a noise — traffic or the chirp of birds — we fidget, there's a flash of light or a change in temperature.
It is what researchers call "cortical arousal" — a brief period of unconscious wakefulness. And, though such arousals affect our heart rate, blood pressure and blood flow (cardiac haemodynamics), they are normal.
But when those nightly arousals become frequent, they can become a "burden."
Researchers who study sleep (polysomnologists) speak of nocturnal "arousal burden": the burden of being aroused at night.
They have shown that arousal burden can disrupt the natural circadian rhythm of the body's cardiovascular system. And that can lead higher blood pressure and insulin resistance.
Now, a study of 8,001 people, spread across various test groups, suggests that there is a link between arousal burden and cardiovascular and "all-cause" mortality — that is, bad sleep can be fatal.
Cardiovascular diseases (CVDs) are the No. 1 cause of death globally. The World Health Organization says "more people die annually from CVDs than from any other cause." At the last count, it was 17.9 million deaths from CVDs in one year.
They say the mortality risks from arousal burden comes down to quality of sleep, rather than how long you sleep.
Watchwords are "sleep irregularity," difficulties getting to sleep and "nonrestorative sleep" — basically, waking up feeling worse than when you went to bed. All that is "associated with increased risk of mortality, irrespective of sleep duration," they write.
For instance, 40% of the women were overweight, 13.7% had diabetes, and 60% had a history of hypertension.
Half the men had a history of hypertension, 13% had diabetes, and 17% had histories of coronary artery disease.
Study limitations
The researchers acknowledge the age and social backgrounds of the participants as a limitation in their findings: "All cohorts comprise predominately white men and women of predominantly middle to older age. Hence, our findings cannot be extrapolated to other races or younger individuals."
On the other hand, it was perhaps useful for the purpose of studying the effect of underlying conditions.
As the WHO points out: "Most cardiovascular diseases can be prevented by addressing behavioural risk factors such as tobacco use, unhealthy diet and obesity... People with cardiovascular disease or who are at high cardiovascular risk (due to the presence of one or more risk factors such as hypertension, diabetes, hyperlipidaemia or already established disease) need early detection and management using counselling and medicines, as appropriate."
Men may experience disrupted sleep or "arousal burden" more frequently than women, but women die more often as a result, a study suggestsImage: Colourbox
So, if you're not getting good sleep on a regular basis, you may want to consult a doctor, regardless of your age or background. It can't hurt to have yourself checked out by a qualified medical professional.
Death statistics over a decade
The researchers recorded how many of the participants had died and from what.
Comparing the results from the first two parts of the study, it appears that 8.4% men and 11% of women died of some form of cardiovascular condition.
The third part of the study, which involved almost 5,000 people, showed deaths of 987 participants, including 344 cardiovascular deaths, over a period of at least 11 years.
The researchers say that "while the frequency of arousals was lower in women than in men, the association with mortality was stronger in women."
They also say they did not consider the effects of any medication that the participants took, and their findings were obtained on a single night (an overnight polysomnography).
They say that there may have been night-to-night variations in arousal burden among the participants, and that may have influenced the "strength of the associations" with cardiovascular and all-cause mortality.
In future studies, the researchers say they may look deeper into the frequency of disrupted sleep and how participants transition from deep to light sleep, with a view to reduce arousal burden and the associated health risk overall.
10 lighthearted takes on pandemic everyday culture
With ever-growing infection numbers and death tolls, the coronavirus pandemic is no laughing matter. Yet the world found ways to keep smiling in 2020.
At the start of the pandemic, people hoarded goods such as toilet paper, leaving store shelves empty. Its scarcity turned it into a semiprecious object and inspired some to create clever signs and comedic drawings that poked fun at its newfound status. This bakery in Dortmund covered marble cake with fondant to make its sugary toilet paper creations, riding the wave of cake-as-daily-objects trend.
Image: picture-alliance/dpa/B. Thissen
Elbow greetings
At the outbreak's start, when droplets were seen as primary transmission pathways and masks were not widespread, people started eschewing physical contact. The handshake was one of the first things to go. Various non-skin-to-skin greetings arose, including the foot tap, the bow and the hand-to-heart. These chess players attempted to elbow bump in March — without bumping their pieces off the board.
Image: Reuters/FIDE/M. Emelianova
Dining with the bear family
When restaurants and cafes reopened after lockdowns, many of them suddenly had unexpected dining guests: giant plush teddy bears. These were used to space out tables and human diners according to distance regulations. When restaurants were forced to close again, some, like the above in Bjelovar, Croatia, left their tables filled with furry families — a sweet gesture in the face of hardship.
Image: Damir Spehar/PIXSELL/picture alliance
Zoom memes
With many people around the world working from home, video conferencing has become part of the daily routine. From accidentally leaving a mic on to revealing our chaotic private lives in a business setting: The comedy potential is endless. Some memes have cleverly reinterpreted history and art through COVID's digital lens, such as this new version of da Vinci's "The Last Supper."
Image: pinterest.com
Coronavirus bedtime stories
COVID-related books popped up over the year, parodies included. One example is, "Goodnight COVID-19," a spinoff of the classic US children's book "Goodnight Moon." Simple lines like, "There was an agitated cat / And grandparents on a video chat" capture everyday reality with a wink. The author hoped humor could help parents talk to their kids about the situation — and, of course, lighten the day.
Image: Independently published
Animal distancing
Can't remember the recommended social distance? Think of a baby elephant! That's what Austria encouraged, saying if you imagine the sizable baby mammal between you and the next person, you'll definitely stay far enough away. If you live in Australia, however, you're supposed to stay one adult kangaroo apart. And the US National Park Service has advised keeping two T-rex arm's length away.
Image: Harald Schneider/APA/picture alliance
Lockdown music
As entire countries went into hard lockdowns in spring, streets and cities were left eerily quiet as public life died. In many places, people tried to lift spirits and fill the silence by making music from their balconies or windows, such as the man above in Oakland, California. In some places, even the police showed off their musical skills by serenading as they made their lockdown rounds.
Image: Reuters/K. Munsch
More than happy birthday
When you're washing your hands more than ever before, there's only so many times you can sing the same handwashing song without getting tired of it. Happily, many people shared their favorite alternatives. These ranged from pre-existing songs with the perfect chorus length of 20 seconds, such as Dolly Parton's "Jolene," to clever mashups of old songs with new coronavirus-inspired lyrics.
Image: Tina Rowden/Netflix/Everett Collection/picture alliance
Funny face masks
Face masks are the essential accessory of 2020. They're seemingly available in every possible style, from high-end designer ones costing three figures to one-off artist creations. And while the masks cover your mouth (and nose!), they don't have to hide your emotions — some humorous designs might even cause onlookers to smile, behind their own masks, of course.
Image: Etsy.com
'Aachoo!'
The famous anonymous street artist Banksy showed sharp humor in his latest mural, painted on the wall of a building in Bristol, England, in early December. An old lady is seen sneezing, dropping her cane and purse while sending dreaded droplets far into the air. But she also launches something else even further from her mouth: her dentures!
