London - Women's brains start going downhill in their 50s - a decade earlier than previously believed, scientists have warned.
On average, the female mind loses up to 5 percent of its sharpness between 50 and 60, researchers found. But they said the drop-off did not seem to be caused by the menopause.
The findings were based on a study that followed more than 2000 healthy women, enrolled in their 40s, for 10 years after the menopause. Researchers from the University of California at Los Angeles said earlier findings had underestimated the drop-off in mental sharpness.
The research 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.