Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
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Cortisol

Cortisol is a hormone that is release by the body in response to stress [ For more on 'stress' go here: http://www.braingle.com/mind/534.html ]. Its effect on the body is to increase blood pressure and blood sugar levels. It also causes the immune system to get weaker, bone formation to decrease and inflammation to lessen. In fact, artificial cortisol, called hydrocortisone, is intentionally used to fight inflammation.

Short-term exposure to cortisol can actually improve memory. This is the method by which flashbulb memories [ For more on 'flashbulb memories' go here: http://www.braingle.com/mind/527.html ] are believed to be formed. Additionally, a small amount of stress can increase the mind's ability to focus on a task. However, long-term exposure to high levels of cortisol can damage the hippocampus [ For more on 'hippocampus' go here: http://www.braingle.com/mind/330.html ] which can cause serious memory problems. It is unclear how much time it takes to cause permanent memory impairment, but finding ways to reduce stress in your life is always a good idea.
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For more mind exercises: http://www.braingle.com/mind/