The Real Reason Operating Rooms Are Green

When you walk into a hospital and want to identify someone who works there, one of the first things you look for is the color of their uniform. From light or dark blue scrubs to green ones, it's really easy to spot healthcare workers. 

For most people, though, this is the extent of their knowledge or awareness of hospital workers and the colors of their environment. If you have been inside an operating room, you may have wondered how anesthesia really affects your body, but did you ever stop to consider the reason why the walls were green? In fact, even with different clothing hues at different hospitals, when in an operating room, you might have noticed that all the staff are dressed in that classic hospital green. It's all thanks to one surgeon named Harry Sherman, who decided that white hospital walls were too bright on the eyes. According to a 2009 paper published in the Canadian Medical Association Journal, green replaced white as the color of hospital walls in 1914. 

Sherman's passion for the color green went beyond it being just a pleasing color to the eye. In fact, he thought that the color he was a fan of, spinach green, was ideal for hospital operating rooms because the iron in spinach has the same chemical composition as the iron that is present in the protein of red blood cells, hemoglobin. While that might sound like a stretch, green does have its merits. 

If you were to take a look at the color wheel, you'd notice that green is positioned opposite red. There is some theory to support why this makes green an ideal color for walls inside an operating room. 

Typically, a surgeon may spend anywhere from a few hours to many hours looking at the innards of the person they're operating on. Peeling their eyes away from all that red and focusing, if for a few seconds, on an opposite and cooling color like green can help give their eyes the ability to effectively refocus on what they're looking at when they turn their eyes back to what requires their attention, per University of California, Davis professor John S. Werner, who studies neurophysiological computations and mechanisms that mediate human vision (via Scienceline). 

Also, as medical expert and U.K.-based junior doctor Dr. Ollie shared on his website, green is a good color to combat the afterimage phenomenon. Remember that time when you were staring at one color for a long time and took your eyes away from it to look at a white wall and ended up seeing traces of the color you were looking at before? "Surgeons may experience this same phenomenon if they're concentrating on the brightly lit blood and tissue in the operating field and then go to look at their colleague's white scrubs." 

Interestingly, green is also linked with less eye strain, possibly explaining why green rooms (where performance artists wait before, during, and after their performances) are green. The color is easy on the eyes, especially after an actor has been exposed to bright stage lights for the length of their time in front of an audience, per The Sydney Morning Herald. As noted by architect William Ludlow during the time when Sherman was advocating for green in operating rooms (via the 2009 study), "White is negative; the convalescent needs the therapeutic reaction of the positive colours that nature has spread so lavishly for her children ... Our eyes were made to find rest and contentment in soft greens, pale blues, an occasional touch of red, but above all, the glorious golden yellow of the sunshine."

The harsh, bright white lights would only be exacerbated if the walls and apparel were also white (per Dr. Ollie). Green provides a soothing and refreshing contrast against which surgeons can rest tired eyes before resuming their work. While the pioneer of green operating room walls may sound like he could've gotten carried away with the color of the leafy green vegetable he modeled his theory on, but his inspiration does have sound logic and scientific reasoning behind it.