Is having dreams every night insomnia? Our nightly sleep starts with a slow-wave sleep period (which takes about 90 minutes) and ends with a fast-wave sleep period (which takes 10-30 minutes), which is a sleep cycle. Slow-wave sleep alternates with fast-wave sleep 4-5 times per night. Slow-wave sleep is an important time for us to eliminate fatigue, recover energy and get deep sleep; fast-wave sleep is associated with dreaming. People who wake up in the morning in the fast wave sleep period will have a memory of dreaming; while those who wake up in the slow wave sleep period may have no memory of dreaming. Therefore, a person who has a daily memory of dreaming does not imply a disease; only if you wake up the next day without a sense of recovery of energy and still feel sleepy, you should pay attention to whether there is a problem of insomnia.