Reading, taking up hobbies and getting involved in arts and crafts in late middle-age can help prevent or delay memory loss later in life, research has shown.

It also suggested that people who watched television for fewer than seven hours a day in later years were 50 per cent less likely to develop memory loss than people who watched for more than seven hours.

The study found that during later years, reading books, playing games, participating in computer activities and doing craft activities, led to a 30 to 50 per cent decrease in the risk of developing memory loss compared to people who did not do those activities.

It revealed people who participated in social activities and read magazines during middle age were about 40 per cent less likely to develop memory loss.

The results add scientific weight to the long-held belief that remaining active both mentally and physically later in life is one of the keys to maintaining good health.

The findings will be presented at the American Academy of Neurology's 61st annual meeting in Seattle, in April.

"This study is exciting because it demonstrates that ageing does not need to be a passive process. By simply engaging in cognitive exercise, you can protect against future memory loss," said the study author Yonas Geda, a neuropsychiatrist at Mayo Clinic in Rochester, Minnesota.

The study involved 197 people between the ages of 70 and 89 with mild cognitive impairment, or diagnosed memory loss, and 1,124 people that age with no memory problems.

Both groups answered questions about their daily activities within the past year and in middle age, when they were between 50 to 65.

Bob Woods, Professor of Clinical Psychology of the Elderly, said the activities recommended were key in developing "reserves" for the brain.

"Essentially, doing these sorts of activities can help build up your brain so that it resists more of the damage that may be happening before the symptoms begin to show themselves.

"It's about building up a reserve of mental strength - people who have less may find that memory loss shows sooner."

Prof Woods said that a Canadian study had found that people who were bilingual had shown a similar resistance to memory loss, which was accounted for because of the intellectual effort required to switch between languages.

He added: "The brain is a dynamic organ, it exists through multiple networks of action and the more those networks are well developed, the more resistance you've got."

Professor Judith Phillips, spokeswoman for the British Society of Gerontology, said the findings proved that, for the majority, retirement was no longer a period of "slowing down".

She said: "Whatever is good for you at a younger age in terms of eating healthily, good physical exercise, doing lots of things, is just as good for you in later life. The more active you can be, even starting activities late in life, can be pivotal in preventing dementia."