Lewis Wolpert likes to keep busy. His latest book, You're Looking Very Well, has just been published and he is already working on the next one. In breaks from writing, he goes running, plays tennis once or twice a week, cycles and has a busy social life - in other words he enjoys an enviably active lifestyle. Nothing remarkable about that, except that Wolpert is 81 years old.
Should we be shocked that this South-African-born retired biologist, is still so active at such a venerable age? According to the latest research we should not. In his book, subtitled The Surprising Nature of Getting Old, Wolpert concludes that your latter years can be the happiest time of your life. Today's pensioners are, on the whole, healthier and more affluent than ever before. They are also more content than their younger counterparts. According to an Austrian-German study of 21,000 people, quoted in the book, happiness peaks at 74.
Wolpert is taking it easy at his London flat following his jog up nearby Primrose Hill earlier in the day. Even he is surprised by this piece of research. He agrees that old age can be a very happy time but cautions: "Everything is dependent on having enough money to live comfortably and on enjoying reasonably good health. As to why people are happiest at this age - it would seem to me that by the time you reach your 70s most of the problems you have had to deal with through your life are solved. You don't have major work problems anymore and you are less likely to have relationship difficulties."
Of course, the picture is not entirely rosy. For those less fortunate, it can be a time of discrimination, poverty and illness. Even Wolpert, who has been luckier than most, has noticed the inevitable signs of deterioration. "When I jog I'm so slow that walkers overtake me. Still, at least both feet leave the ground. Also, like a lot of my contemporaries, I forget things all the time."
In the book, Wolpert recounts the time when he first noticed this forgetfulness. He wondered whether it might be the first stages of dementia. "I intended to ask my psychiatrist at my next appointment. I went to see him and then laughed when I remembered, as I cycled home, that I had forgotten to ask him."
Until six years ago Wolpert was a biology professor at University College, London, and it is the biological elements of the book which are the most fascinating. The good news, he says, is that no scientist in the field has found any specific evidence that we are programmed to die. On the downside, however, this will not stop us from dying. "We are getting some understanding of the ageing process. It's really wear and tear - the same you might get with a car - parts wear out. In our case, the genes get damaged so bad proteins are made. Proteins also get damaged. It's absolutely crucial to bear in mind that evolution only cares about us until we have reproduced. We are required only long enough to give birth to and bring up our children."
Theoretically, there might ultimately be a cure for ageing but this is not something Wolpert thinks is desirable. "Our germ cells [sperm and egg cells] do not age, so there must be mechanisms which we don't yet understand. If we could change the genome in the egg we could adjust the molecular processes to enable us to live longer. But, as I point out, any scientist who did this would be dead before the results were ever known," he laughs, adding that messing around with human genes in this way could have dangerous consequences.
Life expectancy has increased in the past 100 years but this is due to better medicines and healthier lifestyles, he says. There is no magic bullet to slow the ageing process, no single compound which has proved to have any effect at all. So how do we stay young? "The only things that have been proven to have any effect are a good diet, exercise and having a positive attitude towards ageing," he says.
Genes play a significant role but only account for 30 per cent of your life expectancy, as studies on identical twins have proved. Identical twins who had different life circumstances live a different amount of time.
Rather than spend our energy attempting to find ways to live forever, Wolpert is much more concerned that society concentrates on enabling the aged to enjoy a better quality of life - and death. This means increased investment into the diseases of ageing, including cancer, heart disease, and dementia. "On cancer we're doing quite well. On heart disease we're doing moderately well, but the effort and money which goes into researching Alzheimer's is trivial when compared to cancer. And when it all comes to an end I think we have the absolute right to die when we want to. We don't have to go through a long lingering death - I feel very strongly about that."