Blood Pressure and Sleep Apnoea
Hypnagogia BlogIn this post I mentioned that my parents also have sleep apnoea and that my mother was going to have a CPAP trial.
During her trial we noticed something interesting...
Normally she takes medication to reduce her blood pressure, which has improved in recent years but still remains above normal.
On the mornings that she'd been using CPAP for the majority of the night, her blood pressure was lower, in fact it had dropped to a level where medication wasn't necessary.
She took three readings every morning from which we calculated a mean daily morning value. She did this for four nights before using CPAP and for four nights using CPAP.
The results are clear...
I've marked the limits for Hypertension as horizontal lines on the graph. Prior to CPAP my mum had systolic hypertension and borderline diastolic hypertension. Using CPAP she had neither and her blood pressure remained normal even until bedtime.
I would like to explore futher to see if there were any other factors that may have caused this, but just as when I began getting used to CPAP I felt it best to keep things simple and stress free, daily diet and other factors such as bedtimes were not monitored or compared.
My mum quickly got used to CPAP, but due to the fact that she sleeps prone, wasn't able to find a position that didn't cause the mask to dig into the side of her face in the night.
We tried a few different masks, including the CPAP pro. Which she preferred over the Resmed Swift FX pillows because she grinds her teeth in the night (bruxism) and found that the moulded mouthpiece of the CPAP Pro prevented this, but ultimately she decided not to carry on with CPAP for the time being, although she said that the door remains open for the future should she feel the need. She also noted that on a couple of the CPAP nights her bedtime was later than usual due to her not feeling as tired.
It's hard to imagine the pressure that poor sleep, oxygen deprevation, high CO2 and the strain of apnoeas puts on the system, especially when it seems so normal to sleep this way every night but it becomes clearer to see when you have ways of quantifying it such as AHI and blood pressure.
That said, I've read about many people who are hypertensive and CPAP does not reduce their blood pressure. It could be that their hypertension is caused by other factors or maybe even that years of strain on the body through sleep apnoea has caused irreversible damage; I am not qualified to say, I can only speculate.
Additional Reading
Treatment of Obstructive Sleep Apnea with CPAP May Lower Blood Pressure
http://www-archive.thoracic.org/sections/publications/press-releases/conference/articles/2008/abstracts-and-press-releases/barbe-cpap-blood-pressure.pdf
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