Secondly, let me say:
First of all, you should know the key points. They say that infrared rays are emitted by medical stone. You should think of medical stone. Medical stone is just an inorganic aluminosilicate. The infrared rays emitted are extremely weak (for example, your body also emits infrared rays). What heating effect can it have?
Second, infrared rays do have thermal effects, but infrared rays belong to long-wave rays, and their penetration ability is very weak. It can be said that a piece of paper can stop them (exaggerated here), and no high technology can stop them.
Thirdly, when it comes to electromagnetic waves, you should understand that electromagnetic waves are everywhere in the world we live in. For example: light. Light is electromagnetic wave.
Fourth, you have to say you have a fever. Then you must think of the microwave oven. But you know, it's a microwave with a very short wavelength, which makes the molecules in food vibrate and generate heat. Does not involve infrared rays.
Even a little bit from above can make a dead salesman speechless.
Answer supplement:
I went to Xi 'an official website to have a look. In fact, their electric blanket should also be a resistance wire electric blanket, but the material used is added with an ore that may be developed by them (they call it medical stone), which plays a role in assisting blood circulation in the body.