Lighter coloured stains on wood may be better options than darker ones. Burnard and Kutnar tie an oak finish to lower stress levels in workplaces, but found that a walnut one didn’t have the same effect. They report that when “human stress responses were compared in experimental office settings with and without wood. . . . as indicated by salivary cortisol concentration. . . . overall stress levels were lower in the office-like environment with oak wood than the control room [white furniture], but there was no detectable difference in stress levels between the office-like environment with [American] walnut wood and the control room. . . . it is possible to use wood furniture as a passive environmental intervention to help office workers cope with stress.” David Fell’s dissertation work showed that seeing wood grain is a de-stressing experience.
Michael Burnard and Andreja Kutnar. “Human Stress Responses in Office-Like Environments with Wood Furniture.” Building Research and Information, in press, https://doi.org/10.1080/09613218.2019.1660609