This application is not fully accessible to users whose browsers do not support or have Cascading Style Sheets (CSS) disabled. For a more optimal experience viewing this application, please enable CSS in your browser and refresh the page.
Imagine that you're relaxed and drifting off to sleep when suddenly an arm or leg twitches and you have the sensation of falling out of bed. If this has happened to you, you've experienced what sleep specialists call a hypnic jerk or sleep start. Sleep starts happen in normal, healthy people and don't ordinarily require any medical treatment. However, certain medical conditions can make you jump in your sleep and should be evaluated by your physician.
In this deepest stage of sleep, your brain waves are extremely slow. Blood flow is directed away from your brain and towards your muscles, restoring physical energy. REM sleep. REM sleep (this is where dreams occur) â time to get there is approximately 70 to 90 minutes after falling asleep. Your eyes move rapidly, your breathing shallows, and your heart rate and blood pressure increase. During this stage, your arm and leg muscles are paralysed.