This is an issue that is by nature difficult to study in a rigorous, controlled manner. I can tell you that it is a real phenomenon but probably can't prove it in a way you would consider satisfactory. We see the highest levels of this internal body awareness among people who have spent many years using their bodies at peak performance levels. They do their normal daily training and something feels a little "off" before any obvious signs or symptoms appear. But if you only associate with sedentary office workers then you might be skeptical. A lot of people feel like crap so often that to them it begins to feel normal.