Properly treating obstructive sleep apnoea (OSA) may have benefits for the heart and for blood sugar, a study suggests.
If people with OSA don’t use continuous positive airway pressure (CPAP) at night to help keep the airway open, measures of their heart health and blood sugar worsen, researchers found.
“One of the longstanding debates in our field is whether sleep apnoea actually causes heart issues and problems with blood sugar or if they’re just associated,” said senior author Jonathan Jun, of Johns Hopkins University in Baltimore.
In the past, researchers have tried to find a direct link between sleep apnoea, heart health and blood sugar by comparing patients instructed to use CPAP at night to keep the airway open with patients who were instructed to sleep without using CPAP. But one of the major issues with those studies is that people may not actually use the CPAP machine, Jun said.
For the new study, the researchers recruited 31 people with moderate to severe OSA who were known to regularly use their CPAP machines.
The participants slept two nights in the lab, using their CPAP on only one of the nights. The researchers obtained blood samples while participants slept.
The researchers also saw increases in blood pressure and in arterial stiffness, which has been linked with a risk for heart problems
“We are looking at real time changes,” said Jun. “We’re getting blood every 20 minutes.”
As reported online in The Journal of Clinical Endocrinology and Metabolism, on the night without CPAP, patients’ OSA returned. On those nights, patients had low levels of oxygen in their blood, poor sleep and an increased heart rate.
Additionally, their blood samples showed increases in fatty acids, sugar and the stress hormone cortisol.
The researchers also saw increases in blood pressure and in arterial stiffness, which has been linked with a risk for heart problems.
“These were obese patients and patients with relatively severe sleep apnoea. They also had other medical problems,” Jun pointed out. People who fit that description may be experiencing the same changes during the night if they sleep without their CPAP machine, he said.
Glucose and fatty acids rose in the overall group without the CPAP machines, but participants with diabetes may be more vulnerable to the glucose elevation, Jun warned.
He said the study cannot say what would happen to people with milder sleep apnoea.