We have to be thankful considering our number as a family we enjoy very good health generally but you may be sure me and my partner have quite enough to exercise our minds and occupy our attention.

The demographic weight of countries such as China and India exercise a massive pressure on our wages and salaries. They have accomplished massive technological advances and the revolution in information technology has reduced the costs of transport.

As a teacher at Princeton I'm surrounded by people who work hard so I just make good use of my time. And I don't really think of it as work - writing a novel in one sense is a problem-solving exercise.

I've always thought of acting as more of an exercise in empathy which is not to be confused with sympathy. You're trying to get inside a certain emotional reality or motivational reality and try to figure out what that's about so you can represent it.

Core strength and stability is very important to me. Tennis is all about rotation of the body and my ability to create power. I incorporate a lot of abdominal back and glute exercises into my gym sessions.

My workouts include aerobic exercise for a healthy cardiovascular system strength training to maintain muscle tone and bone density core strength exercise for a stable mid-section and stretching to maintain mobility.

Exercise helps me with stress. It changes your brain chemistry. I turn to Ashtanga yoga when I feel the need to relax. I love it but it's not right for everybody. It's taught to you a little bit at a time according to your body type and your strength. That keeps things challenging.

Weight-bearing exercise builds bone density builds your muscular strength so that you can hold your body up where those bones have a tendency to get weak.

One killer exercise that's really great is pull-ups with your legs out level. That's my favourite. It's such functional core strength and that's why I can climb up trees and down vines.

So many older people they just sit around all day long and they don't get any exercise. Their muscles atrophy and they lose their strength their energy and vitality by inactivity.