By keeping my hand in that, it's the way I keep learning. The main way you learn in medicine is by practicing and working with patients.

To be clear, I worry as much about the impact of the Internet as anyone else. I worry about shortening attention spans, the physical cost of sedentary 'surfing' and the potential for coarsening discourse as millions of web pages compete for attention by appealing to our base instincts.

Gardening is not trivial. If you believe that it is, closely examine why you feel that way. You may discover that this attitude has been forced upon you by mass media and the crass culture it creates and maintains. The fact is, gardening is just the opposite - it is, or should be, a central, basic expression of human life.

In the world at large, people are rewarded or punished in ways that are often utterly random. In the garden, cause and effect, labor and reward, are re-coupled. Gardening makes sense in a senseless world. By extension, then, the more gardens in the world, the more justice, the more sense is created.

The kids know what I'm doing when I exercise, and that's powerful. So don't just tell your kids to go play outside. Take a moment off your computer, put on your tennis shoes, hop outside and help them start their game and run off some energy.

I had this one dear friend in college who was a chain smoker. His smoking habits led him to major health problems. That's the time I remember telling him to let go. And after a point, he did listen to me and gave up smoking.

Fitness is really important for my mental and emotional equilibrium as well as my physical wellbeing.

If you get stuck, get away from your desk. Take a walk, take a bath, go to sleep, make a pie, draw, listen to music, meditate, exercise; whatever you do, don't just stick there scowling at the problem. But don't make telephone calls or go to a party; if you do, other people's words will pour in where your lost words should be.