Here is a quote from a foam matress store's website:
During the course of the day, the human body accumulates and stores static electricity. This stored static charge has a negative effect on sleep. Lowering the body's static charge helps the body rid itself of tension and improves the quality of sleep. This is the primary function of the revolutionary Intense cover. Dr. Chris Idzikowsi, one of the world's leading specialists in sleep research, demonstrated that people sleeping on static-reducing Intense were better rested and required less sleep.
Apparently when you get shocked touching a doorknob, you aren't actually disscharging that static charge? Must be so!