How can I check my health in a Seoul subway station?

After a day of shopping I was on my way home and noticed a blood pressure monitor in the station. So I promptly took advantage of this and checked my blood pressure. It was normal. I’ve never noticed a blood pressure monitor in a station before but there were a couple of people waiting to use it after me so I think this is a popular place for one. After all, we should all look after our health!