Burnout is not a real disorder (as far as the American Psychiatric Association is concerned). It's a problem one has with their motivation and is inherently personal in nature. How one gets over their burnout is also specific to them.
Depression, anxiety, and chronic fatigue are true disorders. It likely takes most patients more than 3 days to get over these disorders (if they ever do) but it's likely that a good portion of workers can get over their own "burnout" in 3 days or less.
I've seen all three triggered by overwork, chronic background stress and/or adrenal fatigue. Perhaps it's not an official disorder, but burnout is frequent enough in IT that it probably should be.
Depression, anxiety, and chronic fatigue are true disorders. It likely takes most patients more than 3 days to get over these disorders (if they ever do) but it's likely that a good portion of workers can get over their own "burnout" in 3 days or less.