During a PhD, what should I do that is not research? I am PhD student finishing my first year in Computer Vision. While I take my research seriously, I was wondering what I could (or should?) do that is not research. I can think of very different things:


Studying related subjects that do not directly benefit my PhD as Natural Language Processing;
Studying completely different subjects that interest me: Finance, Chinese, Management, etc;
Go to the gym;
Sleep more;
Play PC games;
Watch movies;
Travel;
Look for jobs for after my PhD;
...


So far, I have been focusing on research during the week, and if I'm tired of it during the evenings or the week-end (which is usually the case), I just rest or read a book. 

Not sure if this is being lazy or having a good life-work balance, but at least I am still very motivated and things are going not too badly (I am quite close to completing the key experiences of my first paper).

So, what should I do?
As the comments say, do what you want.

It is your free time. There is no meed to sacrifice it to your PhD. Otherwise you might later end up feeling that you have "wasted" time, as in this question. Your research work seems to be going well, so there is also no pressure to put in more hours. 

There is no need to optimize every aspect of your life. Try out those things you have mentioned, see what works out for you/what you enjoy more. We cannot make that choice for you.