In a study of 3000 volunteers aged between 65 and 94, just 10 hours of training to improve memory, problem solving skills and reaction times was enough to give the group mental abilities equivalent to people 7 to 14 years younger than a control group who had not received the training.

The test group were given 10 hours of training over a 6 week period and were reassessed 11 months later. Volunteers who undertook 4 more training sessions, a year after the initial lessons, were seen to improve even further in their cognitive abilities.

There are several ways of keeping your mental youth at home, such as learning new skills, doing mentally taxing puzzles such as crosswords and Su Doku or playing difficult, fast computer games where your reactions are tested.

People who have stayed mentally active later in life have been proven to have a far lower risk of developing Alzheimer's disease.

Physical activity is another way of staying mentally alert for longer.

In another study of over 60s, aerobic exercise was seen to cause a marked improvement, especially in the frontal lobes of the brain. These are largely responsible for organisational skills, decision making, sense of humour, attention span and memory.

Regular exercise increases seratonin, helping develop new blood vessels and encouraging the growth of new brain cells and brain connections.

A good diet is also helpful in retaining your mental abilities. A diet high in saturated fats can speed up the decline of cognitive skills.

As the human race becomes healthier every year and average life expectancy continues to rapidly increase, it is worth taking steps, both mentally and physically, to ensure that we make the most of those extra years.