Health Desk:Scientists have warned that women's brains start going downhill in their 50s ? a decade earlier than previously believed.
On average the female mind loses up to 5 per cent of its sharpness between 50 and 60, researchers found.
But they said the drop-off did not seem to be caused by the menopause, noting that there was not a �sharp acceleration� in the decline of mental faculties.
They also said it is not a warning of dementia but a normal feature of ageing and could be held in check or even reversed.
The findings were based on a study that followed more than 2,000 healthy women, enrolled in their 40s, for ten years after the menopause.
Researchers from the University of California, Los Angeles said earlier findings had underestimated the drop-off in mental sharpness.
In two key areas of mental functioning, processing speed and verbal memory, declines were marked.
Verbal memory declined on average by around 1 per cent every five years, and cognitive processing speed, including speed of perception and reaction, showed a decline of 1 per cent every two years. It was not all bad news ? one measure that showed no decline in older women was vocabulary.
The research, published in PLOS ONE, said that up to now �declines in cognitive performance have not been consistently documented in those under 60 years of age�.
The declines form part of normal healthy ageing and run parallel to the slowing of physical responses such as reaction time, running speed and metabolic rate.