— The Conversation (@ConversationUK) December 13, 2015
Work from our lab and from others has found that many of the negative aspects of cognitive ageing seen in older people appear to be linked to the amount of stress they have experienced in their life. We began by measuring the number of stressful events experienced over the lifetime. We looked at a number of factors ranging from experiencing a major illness or losing a loved one, to changing one’s social habits or moving home. Old people who have experienced a lot of stress tend to perform worse on cognitive tasks than those who experienced less stress.
Crucially, old people who haven’t experienced much stress in their life perform just as well on cognitive tasks as young people. This suggests that stress has a big impact on mental ability and that the effect of this only appears in old age. Indeed, young people did not differ from each other in their performance of cognitive tests whatever their life experience of stress had been.
Not only that but the patterns of brain activity of the people taking part in our study reflect the same effect: older people (aged 60 to 80) who have experienced less stress have brain activity similar to that of younger people. However, when it comes to the brain activity of those elderly people who have led stressful lives, we find something very different going on.