[header] How to patch a leak in an air mattress [title] Know that all air mattresses lose air naturally. [step] Before you decide to strip the covers off of you mattress and search for holes, know that no air mattress holds air indefinitely. You will naturally have to re-inflate your mattress whether or not you have a leak. 
[substeps] Cold air, for example, causes your mattress to shrink. As the house cools down at night, your air mattress will likely soften a bit as the air cools.