Article in English: There are four stages of sleep, with the fourth and final stage being REM sleep. In order to get more REM sleep, you need to gradually allow your mind and body to go through the first three stages of sleep. Maintaining a regular sleep schedule and healthy sleep habits will help you do this.  Stage N1: This is when you are transitioning into sleep and lasts about five minutes. Your eyes will move slower under your eyelids, and your muscle activity will slow down but you can be easily awakened by a noise or a sound. Stage N2: This is the first stage of true sleep and lasts 10–25 minutes. Your eye movement will stop completely, your heart rate will slow and your body temperature will decrease. Stage N3: This is the beginning of deep sleep, during which you are hard to wake up and if you are woken up, you will often feel groggy or disoriented for a few minutes. In this stage, your brain waves are very slow and blood flow is directed away from your brain to your muscles, which restores physical energy in your body. Stage N4: The final stage of sleep is REM sleep, or dream sleeping. This occurs about 70 to 90 minutes after falling asleep. You will likely experience rapid eye movement, shallow breathing, and your heart rate and blood pressure may increase. During this stage, your arms and legs are also paralyzed. Keep in mind that during the night, your sleep follows a pattern, moving back and forth between deep sleep and REM sleep. Each cycle lasts about 90 minutes and repeats four to six times during the night. As the night progresses, the amount of time you spend in each stage changes. Most deep sleep occurs in the first half of the night. Later in the night your REM sleep stages become longer. Create a sleep schedule where you wake up and go to sleep at the same time everyday, even on weekends or days off. Sleep requirements vary from person to person, but on average, you should be getting between seven and nine hours of sleep. Having a regular sleep schedule will allow you to experience REM sleep more often, as...

Summary in Vietnamese:
Hiểu về các giai đoạn của giấc ngủ. Duy trì thời gian biểu cho giấc ngủ đều đặn. Tắt tất cả thiết bị điện tử và các thứ làm sao lãng khác vài tiếng trước khi đi ngủ. Giữ phòng ngủ của bạn tối, mát và yên tĩnh. Đừng sử dụng caffeine hoặc chất chứa cồn trong vòng từ bốn đến sáu tiếng trước khi đi ngủ. Cố gắng ngủ sớm hơn bình thường 30 phút.