Less than an hour. According to the health knowledge network, hot spring slate bed, also known as "hot spring tropical zone" and "slate bath". There is a row of stone slabs under the veranda, and hot spring water flows down from the stone slabs, boiling hot. When people lie quietly on the slate, they will feel a special warmth and energy permeating the whole body. It is best not to stay on the slate bed for too long, but not more than an hour. Otherwise, after a long time, it will hurt your back, which will be unhealthy to your body, and the cold will invade your body.