Shedding light on sleep apnea

New studies coming out of prestigious universities like Yale and John Hopkins have shown that obstructive sleep apnea (OSA) is intricately tied to diabetes, liver disease and stroke.

When I first started Insomniac, I had two friends tell me that they had a sleep disorder that caused them to stop breathing.

‘You…you actually stop breathing?’, I asked incredulously.

I had heard of sleep apnea, but I  didn’t know much about it.

So since there’s been a surge of research on sleep apnea, I want to focus this post on making sense of it all.

I was totally unaware that sleep apnea is a very common sleep disorder. It affects nearly 18 million Americans. Obstructive sleep apnea (OSA) is a condition where a person struggles to breath (or stops breathing altogether) because of a blocked upper airway.

This happens in cycles throughout the night.

It’s not easy to test for OSA. It requires an over-night hospital stay. But new research from the University of Sydney could make detection as simple as looking for certain features in a person’s face.

They only tried their new method on 180 patients, so beware of bad science…

Perhaps a more rigorous study from John Hopkins University Hospital, published in the February issue of the American Journal of Respiratory and Critical Care Medicine, showed that factors that have long been tied to obesity are also independently linked to sleep apnea.

Before I move on, it’s useful to know that sleep and weight have been known to affect each other. A dietician from Toronto, writing in the National Post, put it quite simply in her story on sleep as a tool to lose weight.

Basically, leptin and ghrelin, two hormones that regulate weight and appetite, are also affected by sleep. When you lose sleep your body produces more ghrelin, which is responsible for making you feel hungry. Your levels of leptin, the hormone that makes you feel full, will fall.

And we know that being overweight as an adult makes you more likely to develop type two diabetes, especially if you’re obese.

From that we can gather that sleep, weight and type two diabetes may be connected. The team at John Hopkins found that sleep apnea is indeed, linked to insulin resistance, lower levels of activity, and liver disease.

It’s important to note that the study found that these factors were linked to sleep apnea regardless of peoples’ weight. But we know that those factors are also liked to obesity, so there’s some interaction between the two.

Another recent study from the University of Toronto showed that inactivity could be independently linked to sleep apnea and could help explain why 40% of people with the disorder are not obese.

The study found that fluids which naturally accumulate in the legs when you’re sitting or standing could shift to the upper body when you lie down at night and that this could play a role in sleep apnea.

It seems like the more time you spend sitting i.e. the more sedentary your lifestyle, the greater the shift and the more likely it will affect your breathing.

If you haven’t tired of reading about studies, here’s one more.

I was shocked to read that people with sleep apnea are three times more likely to die of stroke, according to a Yale University study published in the Journal of Applied Physiology.

The Yale team found that people with OSA have a decreased ability to naturally protect their brains from stroke. This is explained by the fact that the brain swells in response to decreased levels of oxygen, which can happen when a person stops breathing.

Since people with OSA stop breathing repeatedly throughout the night, the brain ‘gets tired’ and is unable to properly control blood flow. This, I assume, makes one more susceptible to stroke.

So what should I tell my friends with sleep apnea?

A closer look at the studies I’ve just mention, might reveal some methodological problem that will let you say ‘Aha! It’s not true!’.

But since most of us aren’t experts, we trust what we read in the news.