A PhD takes a physical toll on you, but we don't talk about it much

I have been umming and aahing about writing this post because it may come across as a whinge of some kind but it really isn’t meant to be. I think it’s about an issue that needs to be talked about; one related to the kinds of physical stress that come with working for several years on a PhD. We talk a great deal about mental stress, and even the emotional toll that a PhD process can take on students, but I have not yet seen very much written about the physical toll except in a couple of main areas.