There are certain breath techniques that will land you in the clouds. If you do a practice like that without proper grounding, you are likely to be very disconnected from physical reality. That's my opinion and personal experience. In general (and they have the science to back this up) it heightens awareness of your senses. Though people who meditate have higher pain tolerance -- not because they feel less (since they feel more) -- because they have developed willpower to not react to stimulus the same way. Super fascinating!