Mental powers deteriorate from 45

People's mental faculties such as memory and reasoning decline from 45, much earlier than previously thought, according to new scientific research.

The research, published in the British Medical Journal, was led by Archana Singh-Manoux from the Centre for Research in Epidemiology and Population Health in France and University College London,  and based on a study of over 7,000 civil servants aged 45-70, two thirds of whom are men. They agreed to take verbal and written tests on three occasions over a 10-year period. 

It showed average performance in all cognitive domains, except vocabulary, declined in all age groups, even in those aged 45-49 where the decline in mental reasoning was around 3.6%. The results for vocabulary were expected as it is known to be little influenced by age.

The study is important because those who suffer the greatest decline in faculties may go on to develop dementia in older age.

The researchers say adverse cognitive outcomes like dementia are now thought to be the result of long-term processes over at least 20-30 years. Although it is difficult to predict dementia, they say there is enough evidence to show the importance of healthy lifestyles and cardiovascular risk factors in adulthood for dementia. They say: "There is emerging consensus that 'what is good for our hearts is also good for our heads', making aggressive control of behavioural and cardiovascular risk factors as early as possible key targets for clinical practice and public health."