I've been in the martial arts for about 8 years now, through college, university, and employment. While I haven't always been consistent, I did learn early on that the brain works much better when you give the body something difficult to do. This was especially obvious in my university years, when I had time for 4 classes per week, plus the occasional seminar. Despite my high level of physical activity, I found myself smarter, more energized and better rested during that time than ever before.
Now that I work full time and have other responsibilities it is impossible to train quite so much, but I still go to class twice a week and enjoy the many benefits. Since attending any more classes would prevent me from getting enough sleep at the moment, I've been finding other ways to get some decent exercise in on the days I don't have kung fu. I'm working on balancing out my left and right sides to start with and will progress to lifting heavier things as time goes on.
I'm starting pretty slow, with simple bodyweight and kettlebell workouts, usually no more than 10 minutes a time, so I can focus on other things of an evening. I'm also running home after work when I don't want to wait around for the bus. The recent sub-zero temperature was a great motivatior for not standing around outside for 20 minutes at a time. I've been enjoying the run, so I see no reason to stop doing it.
The other side of the coin is to clean up my diet. I've long been a lover of cheese and bread and a number of other unnatural foods, and I'm slowly reducing and eliminating the worst offenders. Since I like watching numbers change, I'm tracking a few basic measurements and statistics in a spreadsheet. The timeline chart in Google Spereadsheets is especially good for this.
I still have a long way to go but it's a fun journey, inspired by websites like Nerd Fitness and authors like Tim Ferris. Good times.