If there's a loud snorer in your house, then you know how disruptive it can be for those within earshot. But in some cases snoring might also be a sign of obstructive sleep apnoea (OSA), a condition that temporarily blocks off airways and could lead to longer term health problems for the snorer themselves.
Up to 20 per cent of middle-aged men could have OSA, which is difficult to diagnose, says Prof Aidan Bradford, a lecturer in the department of physiology and medical physics at the Royal College of Surgeons in Ireland. "Every time we breathe in, we suck air into our lungs and there are complicated mechanisms in normal people to help prevent the airways collapsing. But in people with OSA these mechanisms fail when they are asleep and the airway collapses," he says.
The person may stop breathing for up to a minute, then the brain wakes up a little to re-activate the airway muscles, explains Bradford.
"They are being partially woken up. They don't remember it but they wake up feeling shattered, they feel like they haven't had a good night's sleep," he says.
"There's the lack of sleep effect on the brain but we also think the lack of oxygen is having a bad effect on the brain as well."
His study on an animal model in collaboration with Dr Ken O'Halloran in UCD has found that intermittent low oxygen levels make the upper airway muscles more fatiguable.
This suggests humans with OSA could suffer a vicious cycle of poorly working muscles blocking breathing, which results in low oxygen and, in turn, makes the airway muscles even less effective, according to Bradford.
However, the researchers have also found that anti-oxidant compounds like vitamin C seem to have a protective effect against low oxygen in the rat airway muscles.