Think wrist rests are supposed to support your wrists while typing? Ergonomics experts caution that using this accessory can actually increase stress on your wrists and possibly lead to developing carpal tunnel syndrome. Yikes.
In an article about setting up your workspace ergonomically, president of United States Ergonomics Kevin Costello tells Quartz that the wrist rest is meant to rest your palms on and using it for your wrists adds pressure to the underside of your wrists. Ergo Canada agrees and further explains:
In the vast majority of cases, wrist rests do not provide any significant ergonomic benefit and in fact will usually increase the number of risk factors for injury in your computer workstation. The reason is that if you 'rest' your 'wrist' on any type of support, be it foam, gel, webbing, cloth, etc. you are applying pressure to the underside of your wrist which will compress the tissues, resulting in decreased blood flow. More specifically, you can compress the carpal tunnel and possibly pinch the median nerve, which can lead not only to long term injury, but short term symptoms such as tingling, numbness or coldness in the hands, and finger muscles which fatigue quicker due to reduced circulation.
However, Ergo Canada says that if you use the wrist rest as palm support, that is good, because it reduces the possibility of extending your wrists and experiencing reduced blood flow. Like so: