Below average mental agility raised heart attack risks, the study found

Dr Beverly Shipley from Edinburgh University surveyed the mental agility of more than 6,400 people from across Britain over the past two decades.

She found those with slower reaction times and a poorer memory had a higher risk of dying of cardiovascular or respiratory disease.

Dr Shipley will present the results of the study at a conference in Perth.

Participants in the 21-year study were aged between 18 and 99.

More than 1,500 members of the group had died by 2005, when the research ended.

'Wired together'

Even after taking into account other factors usually linked with heart disease, such as physical activity, blood pressure, body mass index and smoking, it was shown that longer reaction times were associated with higher death rates.

Dr Shipley said the testing suggested that differences in mental ability were a risk factor for certain vascular health conditions.

The results found that lower than average mental agility led to at least a 10% greater chance of developing heart disease.

She said one of the surprising outcomes of the research was that both younger and older adults exhibited the same link between cognition and heart disease mortality.

The researcher suggested one possible explanation from the study was that human reaction time was an indicator of a body with better "system integrity", meaning how well it is wired together.

However, she said: "It's not really clear why cognition and reaction time is related to mortality.

"That's the next step of my work."

About 100 experts are attending the British Psychological Society's Scottish conference, where the research will be presented.