Colors influence energetic aspects of human beings. Color light inside a vacuum/cupping massage glass works through nerval receptors and the aura. The subtle body is surrounded by colors. Each of the 7 chakras has its own color.
Effect of colors to our body system
green: calming and accomodating
red enliving and vitalising
blue: works on the lymph system
purple: takes away stress. Purple the strongest Yin color
If someone feels overloaded these colors will work compensating.
Reference: Book “Licht-Wellness“ (“Light-Wellcness“) by Monnica Hackl