She should stop waking on her own and instead wait for her parent, who has become her alarm clock. 3. As you add 15-minute increments between wakings, she learns to sleep for longer periods of time. Eventually you phase out the wakings altogether and find that your baby is sleeping through the night.
Usually, REM sleep happens 90 minutes after you fall asleep. The first period of REM typically lasts 10 minutes. Each of your later REM stages gets longer, and the final one may last up to an hour. Your heart rate and breathing quickens. You can have intense dreams during REM sleep, since your brain is more active. Babies can spend up to 50% of their sleep in the REM stage, compared to only about 20% for adults.
Usually sleepers pass through five stages: 1, 2, 3, 4 and REM (rapid eye movement) sleep. These stages progress cyclically from 1 through REM then begin again with stage 1. A complete sleep cycle takes an average of 90 to 110 minutes, with each stage lasting between 5 to 15 minutes. The first sleep cycles each night have relatively short REM sleeps and long periods of deep sleep but later in the night, REM periods lengthen and deep sleep time decreases.