I agree that by taking care of the vessel (the body) you take care of the rest (mentation, emotion, etc.). I don't compromise on sleep. If I have some huge exam the next day, I study until it's bedtime, and then I close the books and hope that the grader enjoys mediocrity. It's better for me to have a sharper mind because I am well-rested than to have put eyes on every tiny bit of material.
I detest working out because most of the time it feels uncomfortable, I get sweaty, and I have no athletic skill so I don't even get to feel the pleasure of mastery. Nevertheless, the benefits of exercise feel great! I do tend to drop that ball when I get stressed, which is unwise, but it takes willpower for me to start exercising. It only makes sense that I don't work out when I have no willpower.
A good diet is important as well, and for me that means lots of veggies and not much sugars or carbs. I have very sensitive skin that responds poorly to spikes in blood glucose, dehydration, and exhaustion. If I'm eating sugary crap, if I stay up too late, if I don't drink enough water or I drink too much caffeine/alcohol, I will 100% break out in pimples within a day. The way I look affects my mood, so I try to eat well for many reasons.
For me, I feel most burnt out when my willpower is chronically depleted. When I've been forcing myself to work, study, and make good choices for weeks and months on end, eventually my willpower-er just plain gets tuckered out. That's when I call in the reserves - friends and family who can act as "external willpower-ers." Usually I can get work done if only I get started, and starting is always hardest. If I have a friend who doesn't mind being a bit of a bully, I'm grateful to have them open word docs and put my name at the top of the page, or drag me to the gym, or quiz me on things I must learn. The trick is that you must be willing to perform such services for your willpower buddy when they need it. It sucks to always feel like the locomotive in the relationship, like you're pulling the dead weight of people who can't get their acts together.
This thread comes at an opportune time. I'm beginning to feel a severe lack of care about my current classwork, and it's becoming harder for me to force myself to do ANYTHING. I should take my own advice and do the following:
1. ALWAYS get enough sleep. Sleep time is sacrosanct.
2. Work out at least 2x week. Even 10 min is better than no min.
3. Eat healthy foods and make sure to have snacks available so energy needs are always met.
4. Go find me some external willpower-ers to help me until my own willpower rests up and is back in fightin' shape.
It's either that, or amphetamines.
(I kid, I kid, crank is not the answer)