A study has discovered that older people's brains react differently to chronic stress - which may explain why old adults are always in a bad mood.
Elderly humans are more vulnerable to stress than their youthful counterparts. "There is more low-level anxiety and depression," says Nancy Pachana of the University of Queensland in Brisbane, Australia.
In order to find out the reason, Hirotaka Shoji of the National Centre for Geriatrics and Gerontology in Obu, Japan, put 3-month-old and 24-month-old rats under stress by placing them inside a wire-mesh container for 1 hour every day for two weeks.
Before the starting of the treatment, the two sets of rats had similar levels of the stress hormone, corticosterone.
ll the rats had higher levels of the hormone after two weeks, but the old rats had significantly more. The old rats also showed increased activity in areas of the brain associated with anxiety and decreased activity in regions linked with controlling emotions, reports New Scientist.
The study has been published in Behavioural Brain Research.