How important is exercise for PhD students?

PhD in most science streams (I don't know about other streams) is hard work. Long experiments done on your feet, late night +Early mornings etc. You can not do this and remain lucid enough to make sense unless you have a healthy body. So exercise and healthy food is a must. Otherwise you will not be able to keep it up for 5+ years the degree takes.

In Earth Sciences you are also expected to do all your field work and help other students in theirs. Hence, most Earth Scientists are almost officially required to be of athletic level fitness no matter what they look like (rarely do they look like Serena Williams or The Rock).

What is the best cardio workout for optimal health?

There's a huge amount of controversy about this. Studies have come out left and right on what is healthy and good for you.I'll start off with the usual: It dependsWhat does it depend on:It depends on your goals -- in your case you want to be "healthy". What does "Healthy"

What are some best ways to motivate yourself to workout after waking up?

It's more of a habit and the desire to do it. If you live a simple life, then going to the gym upon waking up is not a problem. You disregard the unnecessary things (cellphone, checking email, internet access on laptop, etc) and focus to make your body healthy. Going

Is it possible for an exercise form to be so bad that it doesn't use muscles?

Muscles will always be used as muscles are responsible for the movement of the human body. The question that you should instead be asking is if the correct muscles are being used, and the answer is no (at least not to their full potential). This is due to compensatory muscles doing the