In the western world, people are living longer. This is good news, but an ageing population also creates social and economic problems, and we have to limit how much we spend. Who cares for the elderly, and equally important, who pays for that care? Should the government ask everyone to save more money for their old age, so they can pay for their own care? Should we also ask working people to pay for the elderly through higher taxes? One answer, of course, is to help older people to keep up their strength, and to stay fit for as long as possible.