In addition to the other good answers, "Yes." It is a situation in which there's no such thing as "being too good", of course. People who've been easily top-in-their-class are now "average" in the population. Very disorienting. Also, as noted, there is a pretense that people "catch up" at super-high-speed by doing 30 hours of homework each week, etc.
So, yes, the pretense, the hype, the mythology, and the disorientation seem to tell people to spend every waking moment "studying".
Among the bad/silly side effects or versions of this is the one wherein one merely frets all day, rather than doing anything constructive. Or "obsessing" about small things, individual homework problems that are of dubious significance, etc. Pointless.
Also as noted, it is important to get sleep, exercise, and reasonable food, to say the least. Chronic sleep deprivation (and dubious diet) is all too typical in the relevant age-group in the first place, and having added seeming-motivations to sacrifice sleep, exercise, and diet just makes everything worse.
As many people have said on many occasions, getting a PhD in mathematics is not a "career choice", because it's waaaay too much work in comparison to the (extra-mathematical) rewards. It only makes sense if one is fairly obsessed with math in the first place, and can continue to have that degree of irrational interest despite workload and temporary loss of self-determination.
That is, by normal standards, it is not reasonable to aim for "a normal life", whether in grad school or thereafter, because it's maybe not possible, any more than performing musicians have "normal lives", whether classical or jazz or pop or... The idea is that it's a hobby that, quasi-miraculously, pays a living. (This is different than engineering, apparently!) If one can keep that feeling, then it's fine!