Just three nights of bad sleep ‘can increase risk of heart attack or stroke', scientists warn

Scottish Sun

12-05-2025

JUST three nights of bad sleep can increase the risk of a heart attack or stroke - even for "perfectly healthy" people, warns new research.
Lack of shuteye triggers molecular mechanisms linked to a greater risk of heart problems, according to the findings - and just a couple nights of insufficient sleep is enough to set those off.
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Just a few days of bad sleep can set of molecular mechanisms linked to increased risk of heart issues
Credit: Getty
Swedish researchers investigated how sleep deprivation affects biomarkers - in this case proteins - linked to cardiovascular disease.
Study leader Dr Jonathan Cedernaes, of Uppsala University, said: "Unfortunately, nearly half of all Swedes regularly experience disturbed sleep, and this is particularly common among shift workers.
"That is why we wanted to try to identify mechanisms that affect how lack of sleep can increase the risk of cardiovascular disease.
"Ultimately, the purpose was to identify opportunities to address these problems."
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A chronic lack of sleep is a growing public health problem around the world, and large population studies have linked it to an increased risk of heart attack, stroke and irregular heartbeat - also known as atrial fibrillation.
The research team studied 16 healthy young men of normal weight who all had healthy sleep habits.
Dr Cedernaes said heart health is influenced by several lifestyle factors, including sleep, diet and exercise.
To separate out the effects of sleep, the research team set out to control other factors and conditions that could trigger heart issues though the laboratory environment of their experiment.
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The participants took part in two different sessions, spending time in a sleep laboratory where their meals and activity levels were strictly controlled.
In one session, the participants got eight and a half hours of sleep for three consecutive nights, while during the other session, they got only about four hours of sleep each night.
Five best stretches to improve sleep
They had blood samples taken every morning and evening for each session.
On the third day of both sessions, people were asked to do 30-minute high intensity workout and had their blood analysed again.
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The research team measured the levels of around 90 proteins in participants' blood, finding signs of increased inflammation in participants when they were sleep-deprived - even if they were "previously perfectly healthy".
"Our findings based on highly standardised in-lab conditions, indicate that even short-term sleep restriction can produce a biomarker profile associated with increased cardiovascular disease risk," researchers wrote in the journal Biomarker Research.
Studies have already linked many of the proteins spotted by researchers to an increased risk of cardiovascular disease, such as heart failure and coronary artery disease.
Dr Cedernaes said: "Many of the larger studies that have been done on the link between sleep deprivation and the risk of cardiovascular diseases have generally focused on slightly older individuals who already have an increased risk of such diseases.
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"That is why it was interesting that the levels of these proteins increased in the same way in younger and previously perfectly healthy individuals after only a few nights of sleep deprivation.
"This means that it's important to emphasise the importance of sleep for cardiovascular health, even early in life."
Top tips and tricks for winding down for sleep before bed
EMILY Robertson, from Mira Showers, shared their top sleep hacks, particularly for during hot weather.
Wind down with purpose
About an hour before bed, start dimming lights around your home.
This signals to your brain that it's time to produce melatonin, your natural sleep hormone.
Think of it as helping your body shift gears from "daytime mode" to "sleep mode."
Disconnect to reconnect
Put away phones, tablets, and laptops at least 30 minutes before bedtime.
The blue light from screens tricks your brain into thinking it's still daytime.
Instead, try reading a physical book or magazine under soft lighting.
Take a warm shower
A 10-minute warm shower about an hour before bed helps trigger your body's natural cooling process afterward, which makes falling asleep easier.
The gentle warmth also relaxes tight muscles from your day.
Try gentle stretching
A few simple stretches can release physical tension.
Focus on your neck, shoulders, and back - areas where we tend to hold stress.
Just 5 minutes can make a big difference.
Sip something soothing
A small cup of caffeine-free tea like chamomile, lavender, or valerian can be a lovely ritual.
Just drink it about an hour before bed so you're not waking up for bathroom trips.
Researchers also found that exercise generated a slightly different response in the body if participants were sleep deprived.
But a number of key proteins linked to the positive effects of exercise increased equally, whether or participants were sleep-deprived - suggesting that some of the effects of bad sleep may be offset by exercise.
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The research team have previously shown exercising when sleep deprived can increase pressure on the heart's muscle cells.
Dr Cedernaes said: "With this study, we have improved our understanding of what role the amount of sleep we get plays in cardiovascular health.
"It's important to point out that studies have also shown that physical exercise can offset at least some of the negative effects that poor sleep can cause.
"But it's also important to note that exercise cannot replace the essential functions of sleep."
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He added: "Further research is needed to investigate how these effects might differ in women, older individuals, patients with heart disease, or those with different sleep patterns.
"Our ongoing research will hopefully help to develop better guidelines on how sleep, exercise and other lifestyle factors can be harnessed to better prevent cardiovascular diseases."