Where there is less sunshine, a preference for cooler, softer colors prevails. Yes, short term physical responses can be measured when different colors are viewed by test subjects. These physical reactions become neutralized when exposed to a specific color for an extended period of time. Red - tends to raise blood pressure, pulse rate, respiration and perspiration, as well as excite the brain waves. Blue - tends to lower blood pressure and pulse rate.
Brain waves tend to decline.
Green - more or less neutral. Dark red, blue, and violet are the least desirable. The choice of colors used in a work environment depends upon the type of work that will be done there. Henner Ertel, director of an institute for rational psychology in Munich, conducted a three year study to judge the impact of environmental color on learning capacity. Rooms with low ceilings were painted in different colors.