Air mattresses especially the ones that are made for SUVs do not really provide the support that is needed for your body. It may not really ensure spine alignment and may not also ensure pressure relief. So, sleeping on an air mattress designed for SUV is okay for once in a while. However, consistent use of an air mattress for SUV can cause stiffness and it may also have a negative impact on your body posture and back. So, use it once in a while but not always.