I understand that current theories link dreaming to REM phase of the sleep. That is when we are in REM phase, we dream. Yet, remembering of the dreaming is not

I understand that current theories link dreaming to REM phase of the sleep. That is when we are in REM phase, we dream. Yet, remembering of the dreaming is not always guaranteed. So it's very much possible to have the REM phase, but no recollection of having dreamt at all. The data on dreams is likely based on self-reports, unlike the REM data which can be measured. So there's a lot of room for speculation on any possible connection and purpose of the dreaming. On thing is for sure, if we can say to remember of the dreaming, we indeed did wake up. In personal experience, I noticed a direct connection between physiological discomfort while sleeping and the related dreaming. That is a discomfort, say in my body positioning would generate dreams around the effect of it, not always literal but often it would either trigger a brief awakening or a change of the positioning. One very stark experience was related to a case when previously frozen (and likely swollen at night) toes were constantly triggering a dream of sleeping next to a campfire and leading invariably to waking up with my knees bent and feet tucked underneath me. Toes healed, the dream was gone. Another very much reliable trigger is airsupply. Say, by odd positioning the breathing is affected, sometimes an external factor can affect the air quality. Sure enough, there will be some dream leading to waking up just to be annoyed at dry/stuffy nose or some random smoke from an open window finding its way in. That I should feel probably grateful about, as it's like an internal smoke alarm... (though no substitute for proper detectors!!) The point is, the dreaming might still be an extension of our survival mechanism. Kind of internal dashboard to check while asleep, no matter how oddly scripted.