Not necessarily, as long as the bed is not too soft. Nowadays, a good quality bed with springs will not cause excessive bending of the lumbar spine when a person sleeps on it. The background to the previous talk of sleeping on a hard bed was the popularity of very soft Simmons in most parts of the country. In fact, as long as it’s not a soft mattress. And even if you sleep on a hard bed, you can still use a mattress to pad it.