Sleeping with your mouth open leads to a dry mouth and increases your chances of snoring. Sleeping with an open mouth also can make it more difficult to breathe, especially for people who have sleep apnea. This is because your tongue and tissues are more likely to sag and block your airway when your mouth is open. Keeping your mouth closed when you sleep isn't easy, because your jaw relaxes as you fall asleep. However, some strategies can help you keep your mouth shut as you snooze.
Sleep on your side or your stomach instead of your back. Your mouth is less likely to fall open in these positions.
Lose weight if you are overweight. Excess weight can narrow your airway making breathing more difficult.
Use nasal strips at night to dilate your nostrils and encourage nose breathing.
Use a chin strap to hold your mouth closed. You can purchase chin straps online or at some drug stores. If you have sleep apnea, your insurance may cover the cost of a chin strap.
Make sure you breathe through your nose and keep your mouth closed as you fall asleep.
Nasal decongestants and steroid sprays can temporarily encourage nose breathing, but do not use these medications for an extended period of time without consulting your doctor first.