When one falls asleep with an open mouth, the jaws relax causing the throat tissues to sag. This makes the tissues to vibrate against the roof of the mouth when breathing air rushes past the upper throat. Further, if the upper body of the sleeper is not adequately supported over the course of a long-hour sleep, the partial blockage in the upper airway may aggravate. The lower jaw hangs loosely, which further constricts the upper airway causing loud snoring.
A mattress may contribute to nighttime snoring while one sleeps on the back, and especially if the mattress does not provide full support to neck and back. If the mattress is too soft, it may not provide sufficient spine support while sleeping. Although, a plush mattress may offer soft surface comfort for sleepers it may not provide adequate support to keep the upper body in an elevated position.
Elevating the head can encourage the jaws and tongue to advance forward, which may potentially clear the snoring problem. However, your mattress needs to support the spine in order to achieve the right head height to clear constricted airway and alleviate snoring.
If you are using even an old mattress that is beginning to sag, it may not help align the spine correctly when sleeping. Further, the sleeping position may even cause the upper airways to become constricted, and snoring to erupt.
In order to reduce loud snoring and avoid a distraction to your bedmate, you have to make sure the mattress conforms to the cervical and lumbar spine curve. Further, you need to ensure that the upper spine is kept straight on the bed in all sleeping positions in order to keep the airways open. The matters should support the neck and head, in particular, to facilitate the air to pass.
If your mattress sags excessively to cause a partial blockage in the upper airway, you should consider changing the mattress. However, you need not go for a firm mattress since that may not support the back curve and may even cause a back pain and shoulder pain. Sleep specialists suggest using medium firm, latex mattresses as the best option to support the lumbar spine and cervical spine forming the upper body. Alternatively, you can place a wedge pillow over the sagging bed.