What Is Cardiac Catheterization? Cardiac catheterization is a diagnostic procedure that involves the insertion of a catheter (a long, thin, flexible tube) into the heart. The catheter is introduced into the body through a vein or artery, usually in the leg, and guided by the doctor toward the heart.
The first REM sleep period usually occurs about 70 to 90 minutes after we fall asleep. A complete sleep cycle takes 90 to 110 minutes on average. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep. As the night progresses, REM sleep periods increase in length while deep sleep decreases. By morning, people spend nearly all their sleep time in stages 1, 2, and REM.
To wake up feeling refreshed you need to wake in between sleep cycles, not during one. It takes approximately 90 minutes to have your first complete sleep cycle and each subsequent cycle lasts an average of 110 minutes (Source - Sleep: Physiology, Investigations, and Medicine).