0424 GMT July 28 2017
If people with obstructive sleep apnea don’t use machines at night to help keep the airway open, measures of their heart health and blood sugar worsen, according to washingtonpost.com.
The study’s senior author, Jonathan Jun of Johns Hopkins University, said, “One of the long-standing debates in our field is whether sleep apnea causes heart issues and problems with blood sugar or if they’re just associated.”
In obstructive sleep apnea, the airway intermittently collapses or becomes blocked during sleep.
The blocked airway causes pauses in breathing. Some people address this by using CPAP — continuous positive airway pressure — machines at night to keep the airway open.
In the past, researchers have tried to directly link sleep apnea with heart health and blood sugar by comparing patients instructed to use CPAP devices with patients instructed to sleep without these machines.
Jun said, “But one of the major issues with those studies is that people may not actually use the CPAP machine.”
For the new study, the researchers recruited 31 people with moderate to severe obstructive sleep apnea who were known to regularly use CPAP machines.
The participants slept two nights in a lab, using their CPAP device on only one of the nights. The researchers obtained blood samples while participants slept.
Jun added, “We are looking at real-time changes. We’re getting blood every 20 minutes.”
As reported in the Journal of Clinical Endocrinology and Metabolism, on the night without CPAP, patients’ obstructive sleep apnea returned.
On those nights, the participants 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 arterial stiffness, which has been linked with a risk for heart problems.
Jun added, “These were obese patients and patients with relatively severe sleep apnea. They also had other medical problems.
“People who fit that description may be experiencing the same changes if they sleep without using a CPAP machine.
“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.
“The study can’t say what would happen to people with milder sleep apnea.
“Because obesity has been tied to an increased risk of sleep apnea, it has been difficult to know whether it is sleep apnea or obesity that is causing those problems.
“The new study, advances that idea that other conditions and not obesity itself are drivers of those levels.”