Just as breathing is made up of contraction (the in breath) and expansion (the out breath), you want to feel this movement as you walk through your apartment. This is done by alternating warm and cool colors.
The cool side of the color wheel (think blues, greens, and grays) is "contracting and calming." So even though your bedroom might see plenty of stimulating situations, its main role is a place to rest, regroup, and relax.
We scanned our Chicago House Tours to find bedrooms that follow this rule of hue.
Top photo: Melissa and Matt's Design Lab