You have to be intelligent, and be able to cope with stress. It is a stressful life, both mentally and physically. Those are the qualities to succeed as a surgeon.

I wish I had known how to “manage up.” I wish I had not believed that my work would speak for itself; the working world requires a bit more than that.

So given a Time Turner, I would tell my 21-year-old self that personal happiness lies in knowing that life is not a check-list of acquisition or achievement. Your qualifications, your CV, are not your life, though you will meet many people of my age and older who confuse the two. Life is difficult, and complicated, and beyond anyone’s total control, and the humility to know that will enable you to survive its vicissitudes.

Never give up your passion for learning. And zoom out of your field before you zoom in. Some of my very best business insights have come from reading around subjects. They have come from approaching questions at a strange angle, from thinking about them from a different point of view. A lot of the knowledge that has really given me an edge in business has come from history, psychology, even chemistry. Connecting seemingly unconnected dots is what has served me well.

Our life here is simple, very simple. Get up in the morning, go for a run, come back. If it is a day for cleaning, we do the cleaning, or we just relax. Then go for lunch, massage, the 4 o'clock run, evening tea, relax, go to sleep. As simple as that.

You run, eat, sleep, walk around - that's how life is. You don't get complicated. The moment you get complicated it distracts your mind.

When I have a lot of pain, I try to confuse my mind to forget about the pain and think about the distance. I don't want pain to be in my mind, because I'd really lose focus on running. After winning, you won't have that pain, but it comes later. The marathon is hard; the second day, you don't go up or down stairs.

When you become a boss, you don't think straight. It's better to be a leader than a boss. That is why I do my share of the cleaning. That is how to show the way to young people. I am trusting that I am leading them in a good way.