By Nick Triggle
BBC News health reporter
Most people would jump at the chance of living longer. After spending 40 years working the thought of a long, relaxing retirement seems appealing.
Experts predict health care costs are going to rise over the coming years
But if a longer life meant an increase in the length of ill health would people still feel the same?
The over 80s population is predicted to double to 5m by 2031, according to the Office of National Statistics.
If the health of the elderly population follows current trends that will mean people spend more of their lives fighting various illnesses.
According to government healthy life expectancy tables published in the summer, the amount of time women can expect to live in poor health increased by 15% to 11.6 years from 1981 to 2001.
For men, the length of poor health rose even more - 34% - to 8.7 years.
Dr Gail Wilson, of the social policy department at the London School of Economics, said: "It's a quality of life question. When we are ill, do we want to be kept alive if our quality of life is not going to get better?
"In this day and age we can have that open heart surgery or live longer with incurable cancer conditions.
"But that does not necessarily mean it will improve our lives for the better.
"We may get into a position where people write living wills, they may not want to be kept alive with a poor quality of life."
And if the ageing population does find itself struggling with ill health, the already over-stretched NHS is expected to feel the strain.
The Wanless report in 2002 estimated NHS spending is going to have to increase from its 2002 level of £70bn to more than £180bn by 2022.
But it is not just primary and secondary care that will have to bear the brunt, experts have said.
A Joseph Rowntree Foundation report in September estimated spending on long-term care over the same period could rise from £13bn to £54bn by 2051.
The study also said the demand for residential and nursing home places would nearly triple to 1.1m.
The government seems intent on dealing with the increased need in elderly care by encouraging people to stay at home - it is cheaper as many receive care from relatives rather than full-time care home staff.
Andrea Lane, of Help the Aged, said this wasn't necessarily a bad thing but what old people wanted was the right to make their own decisions.
"Older people want choice just as 20 to 30-year-olds have plenty of choice," she said
Demand for long-term care is set to triple by 2051, a report says
"That is going to mean they are given the option of staying in their own homes, which most in their 50s and 60s do, or going into a care home, which becomes more popular among the over 80s."
Another key issue is who should pay for long term care. Scotland already provides free long-term care whereas it is means-tested in England.
However, some experts believe an ageing population does not necessarily mean people will spend more time frail and ill.
Sir John Grimley Evans, emeritus professor of clinical gerontology at the John Radcliffe Hospital in Oxford, said US research suggested people can remain fitter for longer.
"The encouraging thing that has been found in America is that healthier lifestyles have meant people are living longer but dying faster.
"That is good for the taxpayer and good for the person. People are remaining active into their 70s and 80s."
Sir John said it was unclear whether the same pattern was emerging in Britain but added it could be achieved.
Healthy food must become cheaper, experts say
"Firstly, people must make intelligent use of health services, such as getting their blood pressure checked regularly.
"But the government must also encourage people more. We should make healthier food cheaper than bad food and there certainly needs to be more education.
"The final aspect is the NHS. If something relatively basic such as a hip replacement is needed, this must be done quickly."
And Sir John also cast doubt on whether an ageing population necessarily means more strain on the health service.
"Apart from at birth and during childhood, most of the costs from a person on the NHS comes during the last six months of life.
"If that happens at 50 or 80, it makes little difference."
Not so, says Professor Ruth Hancock of the University of Essex, who co-authored the Joseph Rowntree report.
She points out that the NHS makes a contribution to long-term care by paying for district nurses to provide care in the community.
However, the problem all academics and doctors face is that no-one is sure what is going to happen, she said.
"People may live longer, or they may not. They may be in better health, or they may not. We just don't know until it happens."