Elderly people deal surprisingly well with stress
There are very few areas where the over-60s’ cognitive abilities deteriorate under acute stress. They even have an advantage over young people when it comes to working memory.
Have you ever been in an interview and suddenly been unable to think of a name because you were nervous? Or have you forgotten what you wanted to say while giving a presentation? Laboratory researchers are confronting their study participiants with similar situations in a bid to find out what effects acute stress has on the brain.
“As yet, research has produced conflicting results as to whether stress diminishes cognitive abilities, particularly in old people,” says Ulrike Rimmele, professor of neurosciences at the University of Geneva and co-author of a new meta-analysis* of the issue by the SNSF’s NCCR Lives. The systematic analysis, carried out by the doctoral student Greta Mikneviciute under the supervision of professor Matthias Kliegel, looked at 19 studies involving around 850 people whose average age was over 60. The results showed that stressful situations had little or no impact on their cognitive abilities.
Indeed, the meta-analysis found only one area where stress had a significantly negative effect – verbal fluency, which involves being asked to name as many words as possible beginning with the letter D within a particular time, for example. Acute stress had virtually no impact on episodic memory, which stores past experiences, or on the executive functions that manage tasks such as systematic problem-solving. Moreover, working memory – responsible for short-term information storage – improved significantly in stressful situations.
These results are particularly interesting when compared with results from young people, whose work-ing memory and executive functions both deteriorate in the face of acute stress. “It’s possible that older people have developed strategies for coping more effectively with stress in the course of their life,” says Rimmele. “Young people have yet to acquire this experience.”
Physiological differences are also presumed to play an important role. For example, stress increases cortisol levels in the blood. How this stress hormone affects cognitive function depends on how many cortisol receptors the brain has. It is known that, in certain parts of the brain, older adults have fewer such receptors than younger people. However, more studies comparing young and old people are needed to understand exactly what effect these differences have.
“In addition, our meta-analysis has identified a lot of other research gaps in this area,” says Rimmele. These gaps now need to be filled. In the future, more knowledge about the processes in young and elderly brains could help maintain cognitive abilities to an advanced age.