Waking up in the morning at camp and realizing that you have a bad back is not a pleasant experience. You'd be lucky to get any sleep at all if you try to sleep on the hard ground especially if you're new or haven't been sleeping hard for some time. You can harden your body by sleeping on the floor at home before the trip or you can use a camping mattress.
Before you go out shopping for camping mattresses, you should know what size you want it to be, depending on your height. Carrying an oversized mat means more weight to carry and carrying one that is too small won't do much good either. You also need to determine what you are going to use it for, whether car camping/music festivals or backpacking. Comfort becomes a priority when weight is not an issue.
Backpackers however need to balance between weight and comfort when choosing a camping mat. It's worth carrying the extra weight for miles everyday for a good sleep at night. At least you'll feel more refreshed in the morning. A camping mattress also keeps you warm at night by providing insulation against the cold ground and keeps your sleeping bag from getting dirty. The temperature ratings on sleeping bags assume that you are using a pad. Some pads can be used as a frame for your backpack.
There are two types of camping mats:
Foam pads are the lightest (and cheapest) option. They can weigh as little as four ounces and seldom go above twelve ounces. These pads have the greatest warmth-to-weight ratio and although they lack the comfort of inflatable mattresses you can use leaves, grass, etc or use it on soft ground to save weight without sacrificing comfort. Another big advantage of foam pads is that there's no need to worry about punctures. This is the cheapest option for camping mattresses.
Inflatable mattresses can either by self-inflating or needs to be pumped. This type of camping mattress is much more comfortable that foam pads but even the lightest inflatable mattress can weigh at least one pound. The biggest disadvantage of this type of pad is that there's a risk of it being punctured so it's important to keep a repair kit handy.
Using Ground Sheets
The main purpose of a ground sheet is to keep dirt and moisture off your sleeping bag and camping mattress. To protect your sleeping bag and inflatable mattresses from sharp points, make sure the ground is free from sharp objects and use a highly durable ground sheet. Some lightweight backpackers use their poncho as a ground sheet. Ground sheets can weigh as little as 3 ounces depending on the type of material.