A Cambridge University professor who warned new students against having a "good time" has been criticised.
Prof Eugene Terentjev e-mailed science first years at Queens' College amid "rumours" of a rise in drinking games.
He advised Natural Sciences scholars that choosing to "enjoy their social life" could harm their grades on the "very hard" course.
A student mental health charity said the message promoted an "unhealthy and dangerous way to live".
First-year science students at Cambridge follow a six-day timetable and must attend twelve lectures from Monday to Saturday.
In his e-mail, reported in university newspapers The Cambridge Student and Varsity, Prof Terentjev, head of science at Queens', told freshers the demanding course would require all of their attention and their "full brain capacity".
"And for a large fraction of you, even that will not be quite enough," he wrote.
"Remember you are not at any other uni, where students do drink a lot and do have what they regard as a 'good time'."
"You are NOT on a course, as some Cambridge courses sadly are, where such a behaviour pattern is possible or acceptable."
After the email was posted on a student Facebook site, hundreds commented on it, most critical of the opinions expressed in the message.
The Cambridge branch of Student Minds, the UK student mental health charity said on social media: "This is an extremely unhealthy and dangerous way to live, and we encourage everyone to enjoy themselves and put themselves first."
A final year natural sciences student at the university told the BBC that while the course was "very intense", it was "so important to be able to balance your academic life and social life and not to feel guilty if you're not permanently working".
Micha Frazer-Carroll, from Cambridge University Students' Union said the email implied "there isn't space for [freshers] to have a social life outside their degrees".
"To offer support regarding drinking culture... could have been a positive thing - words of wisdom on work/life balance. But the email... took neither opportunity."
Reacting to the criticism, a university spokeswoman said: "The university believes that all first-year students in all disciplines, having undergone the thorough admissions process that Cambridge requires, have the capacity to succeed academically."