 Can't find your keys? It happens to the best of us.
But when it is happening a lot and you are forgetting other things too; stress may be to blame!
With less oxygen going to the brain when under stress your short term memory may be affected.
When under stress when tend to breathe shallow not fully inhaling or exhaling. This shallow breathing pattern often becomes chronic. Your brain needs 25% of all of the oxygen that you take in so if you aren’t taking in as much oxygen as you should your brain may be getting shortchanged.
In addition to this Dr. Amy Arnsten of Yale Medical School stated that stressful situations in which the individual has no control were found to activate an enzyme in the brain called protein kinase C, which impairs the short term memory and other functions in the prefrontal cortex, the executive decision part of the brain.
PKC affects a part of the brain that allows abstract reasoning, using working memory that is constantly updated. This kind of memory, the ability to concentrate, seems to be impaired when exposed to mild stresses. | 
