Sleep apnea can worsen the control of blood sugar levels for people with Type 2 diabetes, according to a recent study published in Diabetes Care. Now people with diabetes with sleep apnea have further cause to wear their continuous positive airway pressure (CPAP) masks throughout the night.
Sleep apnea has already been known to cause numerous health problems. The condition causes long pauses in breathing that prevent the body from getting enough oxygen. This puts the body under more stress, and cardiovascular and metabolic problems can arise. Many studies already have provided ample evidence that untreated sleep apnea leads to a higher risk of developing heart disease and type 2 diabetes.
The new study, conducted by Babak Mokhlesi, MD, Director of the Sleep Disorders Center and Sleep Fellowship Program at the University of Chicago, found that when sleep apnea is untreated and obstructs rapid eye movement (REM) sleep, in particular, control of blood sugar worsens in diabetics.
REM sleep is the most restful form of sleep. It typically occurs during the early hours of the morning, when people are in their deepest state of rest and experience dreams. The brain is highly activated during REM. Breathing levels and cardiovascular functions are also heightened.
According to Dr. Mokhlesi, many sleep apnea patients will take off their CPAP masks to get more comfortable as they fall asleep. This prevents the sleep apnea from being treated during REM sleep and may cause people with diabetes to have poorer glycemic control.
“Our study showed that sleep apnea during REM sleep (dream sleep) is more significantly associated with poor glycemic control in Type 2 diabetics than sleep apnea during non-REM sleep,” said Dr. Mokhlesi.
The CPAP mask is designed to push a steady flow of air into the patient’s respiratory system. Without the mask, patients may unconsciously close their airways or stop breathing altogether, depending on the type and severity of their sleep apnea.
“We think sleep apnea during REM sleep is more consequential because it leads to larger drops in blood oxygen levels. The apneas tend to be longer in duration, and as a consequence, the heart rate and blood pressure can rise higher during REM sleep than non-REM sleep,” Dr. Mokhlesi said.
About a quarter of a night’s sleep (assuming a normal sleep regimen of 7 hours) is spent in REM state. According to Dr. Mokhlesi, this is when sleep apnea events can become very severe. After conducting the study, Dr. Mokhlesi feels strongly that sleep apnea needs to be treated for diabetic patients in order to maintain healthy metabolic and cardiovascular health.
“The association between OSA [obstructive sleep apnea] in REM sleep with chronic glycemic control was quite robust in our 115 patients with Type 2 diabetes,” said Dr. Mokhlesi, “In contrast, the association between OSA in non-REM sleep and glycemic control was much weaker.”
“Certainly more studies with more robust experimental designs are needed to confirm these findings,” Dr. Mokhlesi said.