How to prevent physical/psychological health side effects of workaholism in academia and research?

I put my health first by committing to healthy activities that involve other people, so I will have to stick to them.

For example, I

• Have a standing weekly running appointment with a faculty member at my school. I won't cancel this appointment because she will be disappointed.
• Have a standing non-academic volunteer commitment one afternoon each week (giving back to my community is essential for my mental health). I won't cancel this because there's a classroom full of 12-year-old girls waiting for me to come help them with their homework.
• Spend 25 hours each week, from Friday night to Saturday night, completely disconnected from the Internet and anything work related. (I do this as a religious observance, but it's definitely good for my physical health, too!)
• Hold meetings with students and faculty in other buildings in their offices, not mine, so that I am forced to occasionally go outside during daylight hours (if only to walk from one building to the next).

All of these things are non-negotiable to me. That is, no matter what how busy I am or what deadlines are coming up, I will not compromise on any of these things. They're essential to my health and well-being, I arranged them so that other people are depending on me, and so I prioritize them.

First of all. Sleep. And sleep well. Increasing sleep hours increases productivity and not the other way around. Sleep early (people are not supposed to work too late at night) and wake up after good-solid 8 hours of sleep. Then when you wake up, you will realize that you have amazing clarity and excellent productivity. Also, two hours before sleep abandon work and do something relaxing, such as listening to music or spending time with your significant other. Work or stressful activities before bedtime, disrupt your sleep and its quality. So, that leaves you about 24-(8+2) = 14 hours to work which are more than enough.

Devote at least one hour per day on average for exercise. Any sport, workout is better than nothing. Also, try walking. One hour of walking per day does wonders for your heart, lowers stress and you can still think about research while doing it (I do not advice this though). It also alleviates headaches (stress or work related). Also, mind what you eat. Keep your weight steady and do not eat too salty or fatty foods, that inhibit body and mind performance. Use a multivitamin every two days (after consulting your doctor). Also remember that a healthy body always performs better, including mind activities. Also maintaining a good, healthy appearance increases your chances for a fruitful social life, which will prevent you from overworking and overstressing yourself.

And just a reminder. You should not spend too much time on Stack Academia as well :-)

I know that for myself, regular running has helped a lot in the past.

The miraculous thing about regular physical exercise is that even though it takes time, you may find that it seems like you suddenly have more time overall.