One of the most attractive features of an air bed is its adjustable firmness. Using a built-in pump, you can increase or decrease the pressure in an air bed’s chambers, setting the support and comfort levels that are just right for you. Your partner can do the same on his or her side of the bed, and you can modify the settings any time that your needs change.
But while the ability to adjust the firmness of an air bed is a big plus, air beds have some limitations when it comes to supporting your body as you toss and turn during the night. Unlike traditional innerspring and foam materials, which resist compression as you move to provide progressive support and resilience where you need it, air is a passive material. In a typical air bed, air is either not compressed at all (very soft) or fully compressed (very hard), with little, if any, variation between the two extremes. As a result, a basic air bed design may not always support the spine in proper neutral alignment as you sleep, causing you to wake up feeling stiff or sore since your muscles never had a chance to fully relax during the night.
To address this concern, some newer air bed designs have a foam core for underlying support and a thin air chamber located closer to the surface of the mattress. This design lets you adjust your comfort level with the air chamber, but the mattress offers adequate support even when the air chamber is deflated.
Other innovative designs have zoned air chambers running the length of the mattress that can be inflated independently as needed to hold the spine in proper alignment. This approach can prevent the heaviest part of the body, the hips and torso, from sinking too deeply into the bed — a frequent complaint of air bed users.
In addition, some new air beds incorporate eight or more "valve-limited" air chambers that run horizontally along the length of the bed. Each chamber is filled with foam so it has some shape of its own. In total, these air chambers contain a fixed amount of air, which is allowed to flow slowly between the chambers via a series of tiny valves. When you shift positions, the air slowly redistributes across the chambers. Each chamber has a maximum amount of air it can hold — there is no pump. This approach prevents all the air from going to the chambers that support the lightest parts (feet and head), and leaves enough air in the chambers that support heavier parts of the body.
With these innovations in design, today’s air beds can provide a progressive level of support for your spine in neutral alignment, so that when you sleep, the muscles that support your spine can fully relax.