If you have a dry throat in the morning, the first thing you need to look for is snoring and open-mouth breathing, especially if you have sleep apnoea hypoventilation syndrome.
Open-mouth breathing during sleep bypasses the nasal cavity, which has a humidifying and heating function, and can lead to a dry throat at night or in the morning. Apart from a dry throat, you may also notice if you wake up during sleep, or if you have increased night urination, teeth grinding, nightmares, daytime sleepiness, fatigue, headaches, dizziness and memory loss. If you have any of these symptoms, you need to visit an ENT or respiratory medicine department for prompt examination.