Interrupted Breathing During Sleep May Hurt Heart Health

A common sleep-breathing disorder may have more impacts than you might think. Scientists have found that those with obstructive sleep apnoea (OSA) have diminished activity among neurons responsible for keeping heart rate low.

OSA is a common cardiovascular disease that occurs in 24 percent of adult males and 9 percent of adult females. It causes repetitive interruptions of breathing during sleep. Lack of oxygen during these episodes actually brings the person to a light state of sleep or brief wakefulness; these instances of interrupted breathing can occur as frequently as once per minute.

In order to learn a bit more about OSA, the researchers took a look at rats. They caused the rodents to mimic OSA for four weeks and then studied their changes in blood pressure, heart rate and synaptic activity in neurons that control heart rate in the brain.

"Lack of sleep leaves the mind and body tired, leading to poor mental and physical performance, and if untreated OSA increases a person's risk of developing hypertension and irregular heartbeats," said David Mendelowitz, one of the researchers, in a news release. "Therefore it is very important that we have discovered some of the underlying mechanisms that could injure the heart and other cardiovascular tissues. Our study shows that progression of blunted cardiovascular reflexes is accompanied, and likely maintained by, inhibition of neurons in the brainstem that protect the heart and normally maintain a low resting heart rate."

In fact, the study reveals that patients who have OSA and take sleep medication may be at a heightened risk of reduction in neuronal activity that protects the heart. That said, future work needs to be conducted in order to learn more about OSA and how to potentially restore the usual cardio-protective function of these neurons.

The findings are published in the Journal of Physiology.