As millions face the prospect of extending their working lives to fund pensions, scientists have come up with a silver lining.
Retiring later can delay the risk of developing Alzheimer's disease, their research suggests.
It is thought that keeping the brain active by working later in life helps to keep the condition at bay.
A study by the Institute of Psychiatry at King's College London found that education and periods of unemployment had no effect on dementia risk.
Working longer can delay the onset of Alzheimer's, researchers found (picture posed by models)
But each extra year of work delayed the onset of Alzheimer's by an average of 18 months.
The report, published in the International Journal of Geriatric Psychiatry, concluded: 'Extended employment may keep an individual participating in intellectually stimulating activities.'
It added: 'This adds weight to the notion of an active retirement.'
Researchers analysed retirement data from 382 men, about 40 per cent of whom stopped working at the statutory retirement age of 65.
Those who retired earlier did so mainly on grounds of ill health, and the self-employed tended to retire later.
Co-author Dr John Powell, scientific adviser to the Alzheimer's Research Trust, which funded the study, said keeping mentally active and fit in later life was critical for retaining brain power.
'Use it or lose it, that's the message from the data,' he said. 'The thing to avoid is giving up work early and becoming a couch potato.'
He added that the report had comprehensive data only on working men, but the conclusions were likely to apply to women as well.
'In the generation we looked at, women were less likely to work or worked fewer hours,' he said.
Co-author Professor Simon Lovestone said: 'The intellectual stimulation that older people gain from the workplace may prevent a decline in mental abilities, thus keeping people above the threshold for dementia for longer.'
Dementia costs the economy £17billion each year, and one million people are expected to develop the condition in the next decade.
Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: 'There could be a number of reasons why later retirement in men is linked with later onset of dementia.
'Men who retire early often do so because of health conditions, such as hypertension or diabetes, which increase your risk of dementia.
'The best way to reduce the risk is to combine keeping physically active with eating a balanced diet and getting your blood pressure and cholesterol checked regularly.'
Article from Daily Mail