Sleep stages and cycles
We sleep in stages including: stage 1, the lightest stage of sleep; also referred to as “the sleep transition stage” as it is the stage that bring us from wake to sleep, stage 2, when our brain waves form sleep spindles and k-complexes, stage 3, the deepest stage of sleep comprised of delta waves, and rapid eye movement (REM) when we typically dream. We sleep in cycles which typically progress from stage 1 to stage 2, to stage 3, back to stage 2, and then into REM sleep. Adults take 90-120 minutes to complete a sleep cycle whereas babies take only about 50 minutes to complete a sleep cycle (babies typically do not have the full range of sleep stages described above either). It is important to know that it is normal to wake briefly at the culmination of a sleep cycle. At the very least, the brain waves will shift from a stage of sleep to a stage of alpha (i.e., wake) for 3 seconds (i.e., a cortical arousal) at the end of a sleep cycle. If the bladder is full, this is point where some people get up to use the bathroom. If children are used to parents being involved at bedtime (i.e., for sleep transition), they will then at this point go find their parent as they are not yet independent with sleep transition and they are naturally awake and ready to start their next sleep cycle. For kids who are breaking bedtime rules, they might tantrum at that point. If kids or adults have mind racing or sleep frustration, they might experience those symptoms at this point. The key to remember is that the awakenings are normal, it is the behaviors or experiences after the awakenings that sometimes need intervention.