I'm a 55 year old male who works in anaesthesia and especially in cardiothorasics, and have much experience in both inducing and reversing hypothermia.
I started using CPAP machine therapy for my own sleep apnoea in the early winter months of 2017 (January/February) and frequently awoke shivering, even though the ambient temperature was not so low as previously to have caused shivering. At that time I was using the CPAP without warmed and moistened air and kept the machine on the floor, where I did observe it was drawing in much colder air than would be the case higher up.
I moved the CPAP machine such that it was at the same level as my heart. However, the shivering persisted, though not to as great an extent as previously so. My specialist had never heard of this issue.
I then started using the water tank and warming the air and all was fine throughout the summer months. However, despite using the warming unit and keeping the machine at heart level, I have recently started shivering again since the cold winter is drawing in.
On each occasion I ascertained that it was not attributable to hypoglycaemia. My only conclusion, without extended formal research, is that it is down to the CPAP machine forcing in larger volumes of relatively cold air than my body has been accustomed to.
I know from my readings of anecdotes on this forum and elsewhere, that I'm not alone in this experience.
