A pump, either battery powered or plugged into the wall, pumps are into and out of the hollow air chambers of the massaging cuffs or boots.
Various manufacturers will tell you that the air massaging motion feels like human hands, simulates natural blood circulation and simulates the motions of natural exercise to invigorate your body and soothe out soreness, tension and stiffness. For some people, the experience will simply seem like a more novel and slightly more pleasant version of the blood pressure cuff. For others, it can be quite therapeutic, providing both relaxation and invigoration. Much depends on your expectations. If you are expecting an experience exactly like that of a human masseuse, you will probably be disappointed. If you want to get some relaxation and mild therapeutic benefits without paying for a massage or asking someone in your home to wear out their hands giving you a rub-down, you may be quite satisfied with your air pressure massager purchase.
Many product-makers talk about how the air pressure is directed right where it is needed, using microprocessors and "fuzzy logic" to help the air chambers intuitively adjust air pressure in the cuffs or boots to precisely match your particular body type. But in actual fact, an item that you can buy economically online or through a catalog or specialty store isn't going to have advanced computing capabilities, and there are limitations to how much inflatable cuffs can truly adapt to your body to give the perfect massage. Also, because the action is primarily through inflation and deflation of the entire cuff or large portions of it, directing the pressure to a specific spot is not going to be a very precise exercise.
Much of this adaptive power depends on which product you buy, of course, too. Something that gives you various-sized cuffs is going to be limited in how much it can do in the limited area covered by the cuff. Units that encase much of the leg in a single long boot can offer a bit more variety, for example, with steady pressure applied to various zones, from the foot to the ankle/calf to the thigh, for example. A full-leg boot-type device might working upward or downward along the length of the leg and alternate between simply inflating one zone or inflating two or three zones at once.
However, while the air pressure massagers on the market may not truly "know" your body type, you do have options in many cases to customize the massage experience and make it the best it can be for you. For example, variable intensity of the air pressure is a common feature on many of these devices. Some products allow you to choose from a few programmed settings, similar to how some exercise machines will run through particular programs of varying intensity.
In addition, products may allow you to combine vibration and/or heat with the air pressure massage, which can enhance the experience for many users.
Variations on this concept exist for other uses. One is an air-pressure massage for the eyes and face, and some manufacturers have mattress-type units that apply pressure to localized portions of the mattress and, thus, to the portion of your body against that part of the mattress. So, variants of the blood pressure cuff aren't your only option, though they are the most commonly available.
