Adult education charity, Niace, says, in its annual survey, that fewer than a third of 55- to 64-year-olds are involved in any learning.
Many people in this age group do not have any digital skills, it says.
It argues that as people have to work longer, many will lack the skills required to stay in employment.
The National Institute of Adult and Continuing Education surveys about 6,000 UK adults every year.
It revealed that large sections of society, including those from lower socio-economic groups, are less likely to take part in any form of learning.
Niace chief executive David Hughes said the way participation in learning declines as people get older is "pretty worrying" against the backdrop of an ageing society and an expectation that people are going to have to work longer.
The charity said skills gaps and shortages were threatening the long-term future already, and cited figures suggesting a quarter of the UK population would be over 65 by 2050.
Mr Hughes said: "We are pretty worried about the digital area of learning, if you look at the number of people who never got any digital skills, it's dominated by older people.
"Any low numbers of participation are worrying, then you start thinking about the technological changes in the workplace and about the people in that age group not being able to even access government services online."
He added: "Our current economic challenges combined with an ageing population mean people will have extended working lives, learning throughout, which has never been more important."
The charity also called for funding to be protected for English and maths courses, and English courses for speakers of other languages.
And it called for Britain's low-paid workers to be supported through a new career advancement service.
The lack of older people taking part in education and training could leave the UK with a digital skills gap as the population ages, a charity says.