Researchers at the University of California, Irvine, found that stress can cause temporary memory lapses. Laboratory rats were trained to find a submerged platform in a pool. The following day, the scientists gave the rats a stress hormone called glucocorticoids. After a half an hour, the rats were placed back into the pool, but they could not remember where the platform was.
"That particular stress hormone relates to memory and to memory storage," explains Dr. Healy, Dean of Ohio State University's College of Medicine.
Stress causes the brain to produce glucocorticoids, which temporarily disrupt the brain's ability to recall information. However, scientists found that it took 30 minutes for the hormone to kick in. Two minutes after the hormone was given to the rats, they were able to remember where the platform was, because the glucocorticoids had not taken effect yet.
The memory of human beings, like that of rats, is also affected by stress.
For instance: You have studied for a test all night. Yet, when the exam is placed before you, you draw a blank. This is an example of temporary impairment due to the release of those stress hormones. However, Dr. Healy says that the same hormone allows people to remember the moment of stress vividly.
The stress hormone has also been linked to depression, Dr. Healy says.
"A very common illness, depression is associated with elevated glucocorticoid levels 50 percent of the time," Dr. Healy says. "We know that people who have chronic depression also have problems with their memory, both storage as well as recall of memory."
Although short-term stress can help people react faster in a threatening situation, research has shown that long-term stress can wear on the immune system.
"Your immune system gets depressed with chronic stress, which can lead to susceptibility to infections and colds, and maybe even cancer," Dr. Healy says.
Researchers believe that reducing stress is a good way to stay healthy and maintain a sharper memory.