Hello, my fiancee is a male 53 yrs old on Lisinopril, being treated for high cholesterol and increased BP , which of late has been 130/80.... He also sleep apnea, and is on a CPAP, which has not shown any any alerts. The question I have is about his drop in body temperature during sleep. He gets so cold sometimes I think he may have passed. He wakes up shivering and takes a good hour and a hot shower before he can fully warm up. Should I be concerned?