Ask Marilyn

When we’re sound asleep, what keeps us from falling out of bed?

—Lindsay Smith, Littleton, Colo. While we are consciously disconnected from our environment, our brains remain active, and our proprioceptor system, which senses our every movement, stays on the alert as it was trained. Children need side rails until they learn that falling out of bed is undesirable. Seniors may use rails if their systems have grown less acute. Has your doctor ever asked you to close your eyes and touch your finger to your nose? You didn’t use any of your five well-known senses (sight, hearing, touch, taste, smell) to find your way, did you? Rather, you used proprioception. It’s a bit like a sixth sense.