More than 40 per cent of men and women aged 50 and over in England and Wales are couch potatoes who hardly ever exercise. Yet more than half of that 40 per cent believe they are active enough to keep themselves fit.
These findings are highlighted in Physical Activity in Later Life, a report launched last week by the Health Education Authority.
'What is most worrying is the large discrepancy between how fit older people think they are compared with how active, or inactive, they really are,' says one of the report's authors, Dawn Skelton of Imperial College school of medicine. 'Health professionals will have a hard task to convince people to be more active if they feel they are doing enough exercise already.'
The report says 40 per cent of all men and women aged 50 plus are 'sedentary' - participating in physical activity lasting half an hour or longer less than once a week.
The proportion of sedentary women increases with age. Just under 30 per cent of women aged 50-54 are sedentary, compared with 49 per cent of those aged 75-79 and 65 per cent of those aged over 80.
Only one in four men and one in six women over 50 take enough physical exercise to benefit their health - at least half an hour on five occasions a week.
'A lot of disability associated with old age is as a result of disuse, not disease,' says Dr Skelton.
'Health professionals working with older people need to promote the message that being active in daily life can increase muscle strength and flexibility, reduce the risk of falls and help maintain independence and well being into very old age.'
Exercise can also play a significant role in the prevention and treatment of a variety of conditions, including coronary heart disease and stroke, osteoporosis and non-insulin dependent diabetes.
It can also save the NHS significant sums of money. The cost to the NHS of hip fractures caused by falls among elderly people is about£160m a year, and one in five orthopaedic beds is occupied by an elderly person who has suffered a hip fracture. The costs of coronary heart disease are even greater - some£160bn a year, across all age groups.
'There is plenty of evidence that mortality is halved in retired men who walk more than two miles a day and that the risk of stroke is three times higher in those who do little or no exercise,' says Paul Fawcett, spokesman for the British Heart Foundation.
The BHF has joined forces with the Countryside Agency to create 'Walking: the way to health'.
The initiative aims to get people walking in their local community. Three demonstration pilot projects are running in Leicester, Eastbourne and Walsall.
In Walsall, an inner city Victorian park offers three measured walks and permanent wayside markers, each with a health theme, which have been created by a local community arts project.
A separate 'groundmiles' scheme allows people to collect groundmiles - similar to airmiles - when they attend local walks organised by the countryside service. These can be exchanged for goods from local businesses.
But it would help if these stand-alone initiatives became part of mainstream policy.
Bob Laventure, field liaison manager for the HEA's physical activity programme, believes this is now beginning to happen.
'For several years work around physical activity and older people has involved little projects with limited funding and finite timescales.
'Now we are beginning to see it interwoven more into public health policy and local government policy, such as health authority health improvement programmes. This will promote sustainability.'
The 'Better Government for Older People' initiative, run under the auspices of the Cabinet Office, is developing strategies with other partners - including Age Concern, the Anchor Trust and the HEA - that aim to make a measurable difference to the lives of older people.
The initiative puts an emphasis on maintaining mobility and independence, 'and clearly physical activity has a role to play here', says Mr Laventure.
'In the past most of this work would have been led by a HA or local authority physical fitness officer. Now it is becoming more mainstream.' Physical Activity in Later Life. Marston Book Services, 01235-465565.£15.
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Nearly half of women aged 70-74 are not confident of their ability to climb a 30cm step without help.