Please choose the correct ending to complete the given sentence: Health: [header] How to fall asleep again after a nightmare [title] Relax your body. [step] In most cases, a person will wake up suddenly because of a nightmare. This sudden shock to your system from fear can cause your heart rate to rise.

Ending1: By tensing and relaxing your muscles, you may be able to return your heart rate to a normal level and easily drift back to sleep. [substeps] Tightly tense and release muscle groups by beginning at your toes and ending with your forehead. Ending2: Don't allow this to happen-be awake and relaxed throughout the whole night. [substeps] If your body isn't used to this mode, try watching to see if you feel anxious as you sleep-most people experience lightheadedness when they wake up from a nightmare. Ending3: Relaxation will diffuse the energies in the body and improve your ability to relax. [substeps] If you are also experiencing your nighttime nightmare, your nighttime nightmare will likely be to blame. Ending4: Releasing any tension in your body during a nightmare can help relax you physically and quickly. Taking a shower or putting on soothing or noise-cancelling logon masks can prevent you from waking in the middle of an unsettling dream, and improve your body's health.

Answer format: ending1/ending2/ending3/ending4