Both rate of recurrence (speed) and amplitude (height) of these waves changes as you sleep.
Each and every them wake the person up, so someone with poor quality sleep frequently doesn't understand or know he or she is not sleeping peacefully. https://Pr.newsmax.com/article/Garage-Door-Grunts-Expands-as-Premier-Commercial-Garage-Door-Opener-Installers?storyId=668ea40cf31e8e0008dc8f9c