The question of the optimal air pressure in the bed is not easy to answer, because several factors play an important role here. In principle, however, it can be said that the weight of the person and the desired degree of hardness are ultimately decisive.
The air pressure in an air bed should normally be between 0.03 and 0.04 bar (30 to 40 millibars). The higher the pressure in the bed, the harder the airbed. So if you prefer to sleep on a slightly harder surface, just pump in some more air. Good quality guest beds or self-inflating mattresses can easily withstand 120 to 130 kg for one person.