When you look at blood oxygen levels, at least. Watching an interesting BBC Horizon documentary last night, it seems like patients with severe sleep apnoea are in the same league as those who brave the worlds most majestic summit, Mount Everest, when we look at blood oxygen saturation.
In the documentary, a group of doctors set out to climb Everest and collect scientific data. After 5 years of preparation they pulled off some advanced research whilst putting their own lives at risk. One of the goals was to see how low blood oxygen levels would drop. As high up as they could, only just back down again from the ultimate summit (for wind protection) they took blood samples of themselves. A nice graph and summary (of similar research) can be read on this website:
The heart pumps faster and blood pressure rises. Importantly, red blood cell production increases, resulting in an increased haemoglobin concentration, which is required to pick up oxygen and transport it around the body. These mechanisms enable the body to continue to deliver enough oxygen to each cell, despite the lower oxygen levels. At sea level our blood is 98% saturated with oxygen and this decreases to 89% at 3000m and reaches as low as 40% on the summit of Everest.
Sounds like Sleep Apnoea, doesn’t it? Reduced levels of available oxygen puts stress on the heart and causes fatigue. One of our forum members reported oxygen saturation levels as low as 58% during his sleep study. Without acclimatisation, such massive drops can be fatal. When climbing the Mount Everest, the body has time to adjust during the ascend. As Sleep Apnoea develops over time, I guess a similar situation arises where the body tries to cope with the change in oxygen availability.
The mountaineers wore oxygen masks which added just 2% oxygen to the air around them. Not much but it made all the difference. Drawing the parallel to Sleep Apnoea again, CPAP can deliver that vital bit of extra air and ultimately oxygen the body craves so much. It’s interesting to look at symptoms of Acute Mountain Sickness, which results from ascending too quickly:
- Loss of appetite
- Disturbed Sleep
Apart from the vomiting perhaps, that list looks an awful lot like Sleep Apnoea. So next time someone asks you how it feels like, to suffer from Sleep Apnoea you can genuinely say it’s like climbing the world’s highest peak (but without the effort).
The team of doctors in the Horizon documentary hope their research will lead to new, life-saving treatments for intensive care patients suffering from hypoxia, a shortage of oxygen in the body. It doesn’t seem unlikely to me at all this research may also have implications for Sleep Apnoea therapy such as Continuous Positive Airway Pressure.
You can watch video clips from last night’s episode on the BBC website here.
PS Speaking of masks, your next CPAP mask could be free. Win one in the forums here!