78. It takes a toll on your health.

Graduate school is hard on your mental health (see Reason 68), but it is also hard on your physical health. As a grad student, you spend a long time in relative poverty, and healthy living and poverty seldom go hand-in-hand. Your diet is more likely to consist of cheap processed foods than wholesome fare. Your bus rides are especially crowded during the flu season. Your workplace, the college campus, is a notoriously effective environment for the spread of illness. You spend most of your time sitting. And if you are lucky enough to have health insurance, it probably leaves you at the mercy of the student health center.

Especially harmful is the effect that graduate school has on sleep. When you’re faced with a combination of unstructured time (see Reason 61) and endless work (see Reasons 39 and 62), you’re often working when you should be sleeping. On those occasions when you have to meet a deadline, the situation is only made worse. How much sleep do you suppose a teaching assistant gets during a week when she has to read, comment on, and grade 100 undergraduate papers? In college, you might have been able to get away with too little sleep and eating poorly, but your body can only take so much. Graduate school can easily drag on for a decade (see Reason 4), and in the meantime you’re not getting any younger.