Therm-a-rest, as well as others, are now making some pretty thick air mattresses for camping. With the thinner mattresses, you need to make sure that you blow them up as high as you can to get as much padding as possible. But with the thicker mattresses, this is not the case. In fact with a thick Therm-a-rest, blowing it up as high as you would with a thinner model is actually bad because the mattress gets very hard.

When using a thick Therm-a-rest, here's the best way to figure out how much air it needs.

1 - Blow up the mattress as high as you can.

2 - Lie on the mattress in your normal sleeping position and in the location where you will be sleeping.

3 - While in this position, start letting out air.

4 - Continue letting out air until you feel your first contact with the ground.

5 - Once you feel contact, get off the mattress and put in a couple more breaths.

If you adjust your Therm-a-rest this way you'll get the greatest amount of padding possible while still being protected from the ground and all of the stuff on it.