If you're fifty, exercise your mind and body regularly, eat well, and have a general zest for life, you're likely younger - in very real, physical terms - than your neighbor who is forty-four, works in a dead-end job, eats chicken wings twice a day, considers thinking too strenuous, and looks at lifting a beer glass as a reasonable daily workout.

The Element: How Finding Your Passion Changes Everything (ed. Penguin UK, 2009) - ISBN: 9780141911250