A new study found that CPAP therapy at night can lower daytime resting heart rates in patients with prediabetes who have obstructive sleep apnea, reducing their risk of cardiovascular disease.
The study, published Oct 1 in the Journal of the American Heart Association, was conducted by Esra Tasali, MD, director of the Sleep Research Center at the University of Chicago Medicine, and Sushmita Pamidi, MD, a sleep physician-scientist at McGill University in Montreal.
The study’s findings are especially timely, given that people with diabetes or cardiovascular problems are among the most vulnerable to COVID-19.
“Any way we can improve cardiovascular health is more important than ever these days,” Tasali says in a release.
This randomized controlled trial studied people with prediabetes, a condition where blood sugar levels are higher than normal but not high enough to be considered diabetic. Those who used CPAP treatment for two weeks had a drop in their resting heart rate by four to five beats per minute, compared to those who received placebo. Notably, with optimal CPAP treatment, their heart rates were not only lower at night, but also during the day.
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“That’s significant,” Tasali says, noting that a drop of even one beat per minute in resting heart rate can lower the mortality rate and future risk of developing cardiovascular disease.
“A four- to five-beat-per-minute drop in heart rate that we observed is comparable to what you would get from regular exercise,” she says. “Our breakthrough finding is the carryover of the lowered resting heart rate into the daytime and the cardiovascular benefit of that.”
Resting heart rate is key to a person’s health and well-being. A high resting heart rate signals increased stress to the heart. It is a strong predictor of heart problems and death, the doctors say. Prior research has shown that in middle-aged people, every beat-per-minute increase in resting heart rate is associated with a 3% higher mortality rate.
Obstructive sleep apnea (OSA) makes people sleepy during the day and heightens their “fight or flight” stress hormones, elevating their resting heart rate all day and night.
Doctors use CPAP to treat OSA. It keeps a person’s airway open and oxygen levels steady during the night, thus lowers their heart rate. But Pamidi isn’t encouraging people to go online and buy the machine. OSA is a medical diagnosis that must be made by a doctor after a sleep study.
“Our recent findings urge people who have prediabetes, diabetes, or sleeping problems to be screened for sleep apnea,” Pamidi says.
Tasali says, “The majority of patients don’t make a connection as to how their sleep can affect their hearts. With regards to their sleep apnea, patients just think how sleepy they are the next day. I always explain to my patients that sleep apnea can also be harmful to their cardiovascular health.”
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