frank >>reporter: good news for pensioners who are willing to keep themselves active. 84-year-old mary thornton had a knee replacement last year but is still as sprightly as ever. >>old age creeps up and that is the time that people don't realise that they still have to be activeif they wish to carry on a little bit longer... it's no pain no gain. >>reporter: more people like mary means less pressure on already overburdened national health systems. the stagnant economies of europe also tend to have large aging populations, so any overall saving is crucial in this time of cutbacks. >>but it is not just about being physically active and minimising demands on state funded healthcare, a healthy and mobile elderly population can also stay economically active, which could prove vitalto countries facing up to burgeoning pension deficits. >>bonet: the economic benefits over later retirement are obvious. people keep contributing to social securityand somehow their morbidity seems to be lower while you are actively working. >>seymour-newton: mary is an example of somebody who's kept going and she is now