A new animal study has revealed that increased stress hormones might speed up cognitive decline in people as they age.
While most people will experience some cognitive decline as they get older, the extent of these changes and how rapidly they progress varies greatly from one person to the next.
However, the research does suggests that how the body responds to stress may be one of the factors influencing how the brain ages.
The study found that aged rats with high levels of the stress hormone corticosterone showed structural changes in the brain and short-term memory deficits.
Robert Sapolsky, PhD said that older animals with higher levels of stress hormones in their blood have ‘older’ frontal cortexes than animals with less stress hormones, thus, stress may act as a pacemaker of aging in this key brain region.
Older rats with higher levels of stress hormone displayed a 20 percent reduction in the density of dendritic spines (the small protrusions on neurons that come into close contact with other cells to form synapses, the connections between cells) relative to age-matched rats with less stress hormone.
Jason J. Radley of the University of Iowa explained that these findings were not meant to indicate that high stress hormones are the only factor in determining the decline of mental abilities during aging but it does suggest that the effects may be much more widespread than previously thought.
The study is published in The Journal of Neuroscience.