For anyone, there is a limit as to how far you can go as far as staying awake is concerned. Particularly for people in profession, it would be wise to know when to keep on going and when to sleep. As far as medical people are concerned, it has been found that after 16 hours, they better slow down and get some rest if they want to remain competent.

Forced to go beyond that could lead to inconsistency as far as rendering their expertise and that can be more room for danger especially that medical resident people are expected to take care of people in any level of emergency possible as far as health is concerned.

A survey of about 4,000 interns found that in the first year those rules were in effect, 84 percent reported working shifts that violated them at least one month of the year. Forty-three percent reported working more than 80 hours weekly.

(Source) Washington Post

a