Sleep problems like napping, snoring, linked to greater risk of stroke, report finds

Difficulty getting or maintaining sleep, sleeping too long or too little, napping and snoring are all among issues linked to an increased risk of stroke, a recent study found, suggesting sleep problems should be an area of focus for stroke prevention.

According to the study published in the journal Neurology, impaired sleep quality, snoring and sleep apnea are also associated with greater risk of stroke.

The study identifies a link between sleep problems and stroke but does not show that the sleeping problems are causing stroke.

The report found sleep under five hours long, sleep more than nine hours long, unplanned naps and naps lasting more than an hour to be indicators of higher risk.

“Not only do our results suggest that individual sleep problems may increase a person’s risk of stroke, but having more than five of these symptoms may lead to five times the risk of stroke compared to those who do not have any sleep problems,” study author Christine McCarthy, of the University of Galway in Ireland, said in a press release.

The international study, INTERSTROKE, analyzed self-reported symptoms from nearly 4,500 people.

“With these results, doctors could have earlier conversations with people who are having sleep problems,” McCarthy said. “Interventions to improve sleep may also reduce the risk of stroke and should be the subject of future research.”

Why sleep and strokes are connected

The findings make sense to sleep expert Richard Horner, who did not participate in the study but read the report. Horner is a professor in the department of physiology at the University of Toronto and the Canada research chair in sleep and respiratory neurobiology.

People who experience many of the symptoms described in the report, such as difficulty sleeping and an irresistible need to nap during the day, probably have a sleep problem at night, Horner noted.

“So it basically says if you have things that are happening at night which disturb your sleep, the risk of stroke is increased on average one and a half to two times,” he said. “That risk is not trivial.”

The reason behind that is likely because people with sleep disorders are experiencing increased heart rate and higher blood pressure each time they briefly wake up, he explained.

Further, someone with an underlying risk for stroke who, for example, already has high blood pressure to begin with, may have an even higher risk for stroke if they’re waking up in the middle of the night.

When it comes to sleep apnea, which causes “severe snoring” to the degree of “suffocating” at night, oxygen levels go down, he continued.

“And when they’re waking up, all that blood pressure and heart rate response is even bigger,” he said.

“So you can just imagine that sleep disturbances at night are really disrupting the control of the circulation of blood pressure in particular.

“Normally sleep is a state when the heart rests and blood pressure goes down, which is going to be protective against stroke; whereas if you have a sleep disturbance that causes you to wake up frequently and blood pressure is rising quite significantly — maybe sometimes as often as once a minute or so — then yes, your risk of the pipe bursting and leaking causing a stroke is up.”

Tips to get better sleep

According to David Samson, an associate professor in the department of anthropology at the University of Toronto, Mississauga, and the director of the Sleep and Human Evolution Lab, 80 to 85 per cent of people with sleep problems can improve their own behaviours.

“I recommend behavioural modifications before you ever go into a sleep lab,” he said.

Part of that is working on one’s circadian rhythm and timing sleep in accordance with daylight, he previously explained to the Star.

To naturally sync up, people should start their day with 10 minutes outside in the morning to be exposed to light and fresh air.

They should also try to avoid drinking coffee for 90 minutes after waking up to help reduce the later “groggy” feeling that can come in the afternoon. Delaying caffeine for 90 minutes can also make the body’s response even stronger, he said.

At night, it’s best to avoid blue light that comes from LCD screens, such as a TV or cellphone. A light similar to that of fire is better, Samson said.

For those who are feeling sleepy throughout the day, it’s best to skip that nap and “build up fatigue” to ensure a higher sleep quality at night.

And others, who perhaps can’t wake up and go to bed according to the sunlight due to shift work, should note that “consistency is king,” and do their best to go to bed and wake up at the same time every day.

Having one’s last calorie of the day three hours before bed can also help improve sleep, as “metabolism is super connected” to circadian rhythms, he said.

People who are hoping to join a sleep study must get a referral through a family physician.

Correction — April 19, 2023:Richard Horner is a professor in the department of physiology at the University of Toronto and the Canada Research Chair in Sleep and Respiratory Neurobiology. A previous version of this article misspelled his last name.

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