The effects of Stress on Short Term Memory

When someone says the word stress the mind immediately shifts to a negative thought with painful consequences, although stress can be either positive or negative. Negative stress has been blamed for a variety of health

issues as well as psychological and physiological symptoms and problems. It is estimated that millions of pounds are lost in work related, educational and health care costs every year due to stress. While stress is a naturally occurring reaction to the environment around the individual it can be harmful if prolonged or in increased amounts. For the purpose of this paper, we will examine the realms of stress and the impact of stress on memory.

What is Stress?
In a dangerous or unpleasant experience the body reacts automatically to the threat by the brain triggering a number of activities. Stress is defined as a reaction by the body to an internal or external perceived harmful threat, that causes the body to come under pressure or strain (Panzarino, 2006). During an event that an individual feels threatened, physiological triggers in the brain create a state in which many things take place. Chemicals such as adrenaline and Cortisol are released into the blood stream causing defensive actions to take place in the muscles. These chemicals cause heart rate increases which in turn increase blood pressure and blood sugar. The increase in blood flow allows additional oxygen to be distributed throughout the body that is needed for this increased state of alertness and energy. The body basically prepares itself for defensive actions by protecting itself or preparing to run, which ever is most feasible at the time. Most have heard of the term “fight or flight”; this is what is referred to as the stress induced state. If the individual is to flee they will need more energy and the ability to run from the threat. On the other hand if a fight is in order the body must be prepared for extended bursts of strength and endurance as well as healing capabilities. The chemicals released by the brain prepare the body for these reactions to a stressful event. After the threat has ended and the individual is returned to a stage of safety the body will then return to a normal state or a homeostasis.

Types of Stress
Acute
Acute Stress is a type of stress that is an immediate reaction to an external event, such as a car accident or a loud noise. The immediate changes within the body allow the person to spring into action to determine the appropriate action that is needed. Everyone experiences acute stress on a daily basis. Examples include a soft drink spilling or a boss that is having a bad day at work. This type of stress resolves as quickly as it presents, causing no noticeable long-term effects. During acute stress the body and mind are at its very best. All brain functions including memory are very sharp and processing incoming data. The brain is working very hard to sort through the information and commits the experiences to memory for future use. If the stress is continued it can cause memory to be inhibited, but until that point the memory is sharp.

Distress
Distress is exactly like it sounds; a negative reaction to changes in environment, mental or internal events that cause an adverse reaction for the individual. The brain does not accept change without reacting. The brain functions more like a computer and works better under the presumption of a routine. When the routine is changed or altered the body reacts to the stress by setting into action a course of events designed to mitigate any perceived damage.

Eustress
Stress does not necessarily have to be a negative event that triggers the body to respond. Positive stress or eustress is referred to as a positive event that causes an individual to assume a fresh look on life and keep them engaged in living. Stress is the body’s natural reaction to changes in the environment regardless of whether they are positive or negative. For example, the birth of a new child places stress on the mother, but in a positive manner. Eustress has been linked to positive effects on memory in terms of new experiences and memories. Since eustress is typically not a prolonged state it poses little threat to the body and unlike its counterpart, distress, seldom becomes chronic.

Chronic
Acute stress, eustress and distress are normal reactions as a part of life. The concern and problems come in when the body continues the cycle of stress known as chronic stress. Chronic stress has been linked to serious medical concerns as well as psychological issues. Chronic stress weakens the body’s immune system making the individual more susceptible to illness (Miller, 2002). The frequency and duration of the body’s reaction to stress that is placed on organs of the body can also cause them to break down and begin to weaken leading to heart attacks, strokes and other serious conditions.

The brains activity during stress:
The brain is where the origination of activity transpires when the body is in a state of stress. When an individual perceives a threat there are several hormones that are released. For example, if you are crossing the street and a speeding car turns the corner and is heading for you, your body enters into the stress reaction possibly before you even realize there is a threat. One of the first things that happens when faced with an immediate threat is the neurotransmitter adrenaline is released into the bloodstream in order to increase heart rate and change the rate of flow of blood. The organs necessary for survival are supplied with oxygen rich blood and all others are silenced. The pituitary gland releases the hormone known as adrenocorticotrophin (University of Pittsburgh, 2006). The adrenocorticotrophin is responsible for triggering the release of Cortisol in the adrenal gland (Miller, 2007). Cortisol is a very important hormone that is needed to free up energy stores and help restore the body to a normally functioning level. After the threat has subsided the body must restore normal energy levels and eliminate the excessive hormones that are circulating throughout the body. Cortisol assists by signaling the release of blood sugar from the liver as well releasing stores of fat for energy use. Cortisol can be said to organize and facilitate the hormones and neurotransmitters during the stressful event (Luipen, 2005). The release of Cortisol is a positive hormonal release for the body, but in cases of chronic stress the body can become accustomed to the additional need for Cortisol therefore increasing the demand. When this happens it can lead to health issues such as hypertension and heart disease (National Institute of Health, 2002).

While the body is involved in sustaining safety, another very important activity is transpiring. During the release of the hormones the hippocampus is also engaged in a very important task. The data is stored in the hippocampus for a period of time and then moved into the cerebral cortex for long term storage. This is very important in the area of learning because it provides the individual experience to avoid another stressful situation or event. That is how we learn by experiencing then having the ability to access the information at a later date. In some cases the hippocampus is deprived of glucose because of continued stress it can cause permanent damage. The hippocampus is taxed with making new memories in order for storage and use at a later date. If the decreased glucose level is continued the hippocampus becomes unable to produce new memories. This happens many times in traumatic events and the individual is unable to remember the event. In case of reduced hippocampus ability it can not only inhibit memory but it can also inhibit the ability to learn. In a recent study with mice, researchers found that stressed mice were much slower in the learning process than their unstressed counterparts. The research concluded that stress causes a “fuzz like” symptom because of the slower cognitive processes (Pawlak, 2005).

As we know chronic stress and even perceived stress can result in higher levels of cortisol. Cortisol has been linked to decreased memory as well as neuronal death (Neuroanatomy). Patients suffering from Post Traumatic Stress Disorder were found to have a 10% reduction in the hippocampus (Neuroanatomy). This suggests that with repeated and chronic stress the release of the hormones can cause irreparable damage to the hippocampus, causing memories and functioning to diminish.

Symptoms of Stress:
Individuals react differently to stress and no two individuals are alike, but many have similar symptoms. Symptoms can be physiological or psychological. Either category can be detrimental to memory, learning and general feeling of wellness.

Physical symptoms are the first reactions that the individual notices to a stressful event. People are different, but many are affected in similar ways to a stress induced state. Many suffer from a pounding or racing heart, which is in reference to the increased hormones released. With the influx of hormones it is not uncommon for the individual to experience nausea or abdominal pain. This is sometimes referred to as a hormone dump, when the individual suffers from nausea during or after a stressful event. Sweating, shortness of breath and diarrhea are also common physical symptoms of stress.

As well as physical reactions there are a number of psychological or emotional symptoms to stress. As noted earlier when the cortisol is released into the bloodstream during a stressful event there can be marked mood swings (Miller, 2007). Emotional outbursts can also accompany and negative feelings. Many faced with a stressful event will feel as if they can not make a decision and have a lack of coping skills. This is because under pressure the brain has diverted all attention to surviving leaving the individual flooded with stimulus. The increased cortisol in the body interferes with the ability to think (Salposky, 2000). The brain typically reacts to the primary threat leaving other functioning lacking until the perceived threat has ended.

Stress and its effects on the body:
Not all stress is bad in fact it is not the stress state that is bad at all. Stress is your body’s reaction to a threat, which is a good thing. If your body did not react you would not be able to move or react in time to avoid harm or injury. Stress is a state in which the body allows more energy, which can work to the benefit of the individual. Example of how stress can give an edge is an athlete in a sporting event or a student waiting outside an examination room. That stress helps prepare the body for the feat that it is getting ready to undergo. Short periods of stress and the hormones produced by the brain can sharpen memory with the boost of energy that is given by the releasing hormones. This energy which is glucose can be used in productive manners in remembering and assisting the mind in categorizing the incoming data.

This short-term surge of hormones and other chemicals produced by the body can allow the individual to have a sense of well being. Not only does the body undergo the physical changes that allow the person to sharpen their senses, it also improves memory.

Stress and Memory:
Short-term memory is often called the working or primary memory. It is the area of memory that is responsible for the complex cognitive processes such as logic, reasoning and learning. Information is stored in the short-term memory for seconds, minutes and up to about thirty minutes. After the period of time has elapsed some of the information is moved into long term memory.

Many researchers have studied the effects of stress on memory. To expand on the earlier statement of deprivation of glucose to the hippocampus, it is apparent that damage can result causing impaired memory and learning abilities (Pawlak, 2005). In a study conducted with laboratory rats, scientists have found that when rats were subjected to ongoing stress there were physical changes within the brain. Chronic stress was found to alter the neurons in the hippocampus, causing a decrease in dendrite spines and NMDA receptors. The dendrite spines and NMDA receptors are two structures necessary for memory (Pawlak, 2005). It was found that the rat’s memory and learning ability was severely impaired. The hippocampus is responsible for recollections such as people, places and events and since the damage takes place within the hippocampus it is only reasonable to make the determination that short-term memory is negatively affected.

Researchers have also questioned whether or not factors such as age and gender have any difference when evaluating the effects of stress on short-term memory. In a study conducted by Elzinga it was found that there are differences in the effects of Cortisol between gender and age (2005). In the study they found that men were more susceptible to the impact of Cortisol than women (Elzinga, 2005). Another very important factor found in a study conducted by Kleen, was rodents subjected to stress exhibited inhibitory reactions consistent with depression (2006). The rats were found to have decreased motivation and an increased adrenal size. The adrenal gland is located above the kidneys and is responsible for the production of dehydroepiandrosterone (DHEA), Cortisol and adrenaline (Elzinga, 2005). In a recent study conducted at the University of Miami found that college students that experienced thoughts of painful or stressful situations, though not traumatic had an elevated level of cortisol in their saliva (McCullough, 2007). This signifies that the brain quickly retrieves the previous data and stress event triggering the biochemical reaction. In another study it was found that individuals that were given a 30mg cortisol were less negative after a stressful event than their control group counterparts (Het, 2007). The control group was given a placebo and found to be in a worsened mood with symptoms of negativity after a stressful event. The cortisol was found to help protect mood and negativity during and immediately following a stressful event (Het, 2007). The production of the adrenal glands decreases over time and dwindles in older adults, therefore, causing fatigue and a lack of motivation (Brennan, 2006). As documented by numerous other sources it is a well-known fact that fatigue and lack of motivation can cause short term memory to suffer.

On a lighter note, research has found that the Cortisol induced inhibition of short-term memory is reversible. Elzinga documented that though working memory was inhibited in the Stress State, the rats returned to normal functioning after only ten days of non-stress situations (2005). Signifying with appropriate coping and managing stress individuals can ensure their health. There are a number of ways in which individuals can reduce the effects of stress in their lives. Exercise, proper diet and relaxation techniques can help with releases for built up tension and stress for individuals. Exercise has proven very effective in stress reduction.

Stress is a normal part of human life and the manner in which the body protects itself is miraculous. When all is working correctly there is not a problem with the additional hormones or neurotransmitters produced, but in excess can become problematic. Research has shown that the body’s reactions to chronic stress can cause a host of medical conditions as well as inhibition and problems with memory. The effects of stress can be minimized with appropriate actions and awareness. Many studies have addressed the benefits of exercise and relaxation techniques as ways to alleviate everyday stress experienced by people. Alleviating recurring stress can prevent it from accumulating to a point of chronic stress and therefore negatively affecting the body’s normal functioning. A positive step towards addressing stress related health and memory issues is understanding the process by which the body protects itself as well as when a person may be experiencing more than normal stress levels.
Results Analysis

Analysis of Questionnaire

During the initial phase of this study, participants were asked to complete a self-assessment questionnaire. The purpose of the questionnaire was to obtain information regarding the perceived stress experienced by the participants. A total of 25 responses were recorded for each question. In a question relating to short-term memory, the test group made up 52 percent of the respondents while the control group made up the remaining 48 percent. Thirty-six percent of the total respondents reported their short-term memory as being good. Of those reporting “good” short-term memory, 16 percent came from the test group and 20 percent from the control group. Sixty percent of the participants reported short-term memory as “average.” Test and control groups broke down to 32 percent and 28 percent respectively. The remaining four percent self-reported “poor” short-term memory, all of which came from the test group. From a gender perspective, 48 percent of the participants were male and 52 percent were female. Twenty percent of the males and 16 percent of the females reported “good” short-term memory. Likewise, 28 percent of the males and 32 percent of the females reported “average” short-term memory. The remaining four percent reporting “poor” short-term memory came from the female group.

In a second question relating to long-term memory, the results indicated that 24 percent of the test group and 20 percent of the control group reports long-term memory as “good.” Twenty-four percent of each group reported long-term memory as “average.” The remaining eight percent reporting “poor” long-term memory were from the test group. When breaking down according to gender, we found that the male participants reported long-term memory as “good”, “average”, and “poor” at a rate of 8%, 32%, and 8% respectively. Of the females reporting, 36 percent stated “good” long-term memory and 16 percent stated “average” long-term memory. No females reported “poor” long-term memory.

In a question relating to stress, the possible answer choices ranged from never, sometimes, often, and all the time. Of the total responses, four percent reported never feeling stressed, 60 percent stated they sometimes feel stress, and eight percent advised they feel stressed often. Another four percent reported that they feel stressed all of the time. When analyzed for gender only, males reported feeling stressed only sometimes or often at a rate of 28 percent and 20 percent respectively. Females reported “never” feeling stressed or “feeling stressed all of the time” four percent for each category. Females most often reported “sometimes feeling stress” at a rate of 32 percent. The remaining 12 percent of females reported “often feeling” stress.

Analysis of Pulse Rate.

Group Differences in Pulse Rate for Memory Clinic Test 1. The autonomic nervous system releases hormones during periods of experience stress. The most commonly observed autonomic effects seen in most individuals are an increased heart rate, and breathing. These two effects are largely controlled through the sympathetic nervous system and the endocrine system. For the purposes of this study, how these systems contribute to an observable change in the pulse rate and blood pressure were examined. According to the literature, adrenocorticotrophin triggers the release of Cortisol, which organizes and facilitates the release of hormones and neurotransmitters during a stressful event (Luipen, 2005). Adrenaline is released into the bloodstream in response to stress, which causes the pulse and blood pressure to increase.

The results of the study indicate that the pulse rate, prior to clinical treatment to stress averaged slightly more that 80 beats per minute. At the conclusion of the clinic treatment to stress, the test group showed a slight increase in pulse rate to between 90 and 100 beats per minute. The control group exhibited only a miniscule increase during this phase of the experimentation process. No significant differences were observed either prior to or post clinical treatment.

Gender Differences in Pulse Rate for Memory Clinic Test 1. The gender differences observed prior to memory clinic 1 showed no statistical significant differences among the means with regards to observed pulse rate. The female control group exhibited a pulse rate of 80 with the males being slightly higher. The test group for each gender showed males to be slightly less than 80 beat per minute and females to be approximately 90 beats per minute. There were no absolute significant differences among the groups. However strictly among females, the pre-test results were nearing statistical significance between the control and test group. Posttest results indicate that both female and male respondents measured pulse rate changed by an insignificant amount for the control groups. The test group presented a slightly more observable increase with males showing the greatest overall change in pulse rate. A statistically significant difference among the means was observed between the female control and test groups. No other significant differences were observed during this phase of testing.

Group and Gender Differences in Pulse Rate for Memory Clinic Test 2. Memory clinic test 2 provided similar results. Pre-test females and males measured pulse rate was unremarkable from pre-test measurements prior to memory clinic 1. The post test results showed very minor changes among both the control and test groups in females and males. The results provided no statistically significant differences in any group or gender.

Comparison of Results the Current Literature. The results of the application of memory tests tend to provide limited support for the literature assertion that the induction of stressful events increases an individuals pulse rate (Panzarino, 2006). The differences observed between pre-test and post test measurements between the control and test groups provided no statistically significant results that fully support the hypothetical statement that stress causes the pulse rate to increase. However, the data does tend to show that stress and pulse rate may be correlated at some level and further studies may provide observations that are more significant.

Analysis of Blood Pressure.

Changes in blood pressure have also been enumerated as a physiological change in those subjected to stressful events. Blood pressure has also been associated with the release of hormones and neurotransmitters during a stressful event (Luipen, 2005). For the purposes of this study, a sphygmomanometer was used to measure the diastolic and systolic blood pressure of all participants.

Group Differences in Blood Pressure for Memory Clinic Test 1. According to the results of memory clinic 1, the mean diastolic blood pressure among both groups was approximately 80 mm/hg both pre-test and post test. No statistically significant differences among the means were observed. The systolic measurements were similar among the groups and again no statistically significant differences were observed.

Group Differences in Blood Pressure for Memory Clinic Test 2. When examining the results of memory clinic 2, the results mimicked those observed during memory clinic 1. Both pre-test and post-test diastolic measurements provided no significant change and were not significantly different from those observed during memory clinic 1 testing. Systolic blood pressure measurements were relatively unchanged from those observed in memory clinic 1, both pre-test and post-test.

Gender Differences in Blood Pressure for Memory Clinic Test 1. Gender differences were also analyzed to determine if stress affects males and females differently. According to the results of memory clinic test 1, both the female control and test groups showed little or no change in either diastolic or systolic blood pressure for pre-test and post-test measurements. Males tended to show little or no increase in both the control and test groups during this phase of testing also. No statistically significant differences among the means was found for either gender both pre-test and post-test.

Gender Differences in Blood Pressure for Memory Clinic Test 2. Memory Clinic 2 yielded results very similar to memory clinic 1. Pre-test males showed a very insignificantly higher diastolic blood pressure measurement than did other categories. This same reading was also reflected in the systolic measurements, however no significant differences were observed for either gender or group.

Comparison of Results the Current Literature. The existing literature generally supports the conclusion that the sympathetic nervous system and the endocrine system affect the release of hormones that reflectively affect an individual’s blood pressure when exposed to a stressful event (Panzarino, 2006). However, these same results were not found in this particular study. No significant changes were observed between the control and test groups. Likewise, no significant differences were observed between genders. Blood pressure did not change by a measurable amount when accounting for short-term or long-term memory. These results tend to support the assertion that we would reject a null hypothesis purporting that stress causes an increase in blood pressure. Again, additional testing would be necessary to exclude blood pressure as a reaction to stress exposure completely.

Analysis of Salivary Cortisol Levels

Cortisol has been purported to be the primary reagent contributing to release of hormones and neurotransmitters when an individual is presented with a stressful situation. Cortisol is released as a secondary product of the pituitary gland (Miller, 2007). The primary function of cortisol is to facilitate the release of blood sugar from the liver and stores of fat for energy sue during a stressful event. To examine the changes in cortisol levels in participants, an ELISA testing kit was used.

Group Differences in Salivary Cortisol Levels for Memory Clinic Test 1. For memory clinic 1, the salivary cortisol levels were measured both pre-test and post-test. There were no significant differences among the means found before the testing for between the control and test groups. Post-test results showed a very slight increase in the control group, elevating from less than 2 ng/L to slightly more than 3 ng/L. Those participants subjected to the stressful event yielded a much more observable increase in salivary cortisol levels. Participants pre-test measurements were approximately 2.5 ng/L and significantly increased to approximately 6.5 ng/L. This change in salivary cortisol levels provided a significant difference among the means for the test group.

Group Differences in Salivary Cortisol Levels for Memory Clinic Test 2. Memory clinic 2 showed pre-test result that were similar to memory clinic 1. However, the post test results provided less dramatic changes. The test group’s cortisol level increased from about 2 ng/L to just over 4 ng/L. These results provided no significant differences between the two means.

Gender Differences in Salivary Cortisol Levels for Memory Clinic Tests. Gender differences were also analyzed. Salivary cortisol levels for females and males increased slightly for both control groups during memory clinic 1. The female and male test groups yielded significant differences. Female and male cortisol levels increased from between 2 ng/L and 3 ng/L to well above 6 ng/L. The results of memory clinic 2 also showed increase in salivary cortisol levels. Female test participants showed a significant increase in cortisol levels after subjected to the stressful event. Male test subjects showed an increase but the results were not significantly different among the means.

Comparison of Results the Current Literature. The results of the salivary cortisol measurements tend to support the generally accepted literary conclusion that cortisol levels and stress are positively correlated. An increase in exposure to stress tends to cause and increase in cortisol release. For the purposes of this study, measurement of salivary cortisol provided the most conclusive evidence to support the hypothesis that stress affects memory.

Results of Memory Clinic Tests

Group Differences in Memory for Clinic Test 1. During memory clinic test 1, each participant was given 3 minutes to memorize a series of handouts containing pictures words and numbers. The test group completed a simulated stressful event while the control group remained “at ease.” At the conclusion of eight minutes, the participant was asked to fill in the missing element from each of the handouts. These results were then analyzed and recorded. These results indicated that of the test group, participants were able to correctly identify approximately 5 of the missing elements correctly. The control group, who rested, was able to correctly identify slightly less than 7 missing elements. There appeared to be no significant differences between the means of the two groups.

Group Differences in Memory for Clinic Test 2. Two weeks after memory clinic 1, memory clinic 2 was conducted to determine if any differences existed in memory retention among the control and test groups. The same testing criterion was followed except for the time allowed for handout review. According to the finding of memory clinic 2, both the control and test groups scored almost identically in correctly identifying the missing elements from the handouts. Each group’s scores clustered around identifying two out of twenty missing elements.

Gender Differences in Memory for Clinic Test 1. During this analysis, gender differences were also examined. During memory clinic 1 the female control group scored more than six out of twenty missing elements while the test group who were subjected to the stressful event, scored only four missing elements correctly. The male control group for this same clinical testing phase correctly identified approximately seven missing elements. The male test group identified six of the elements correctly. No significant differences among the means were observed for the female and male groups as observed by gender. In addition, no significant differences were noted between the gender variables.

Gender Differences in Memory for Clinic Test 2. Gender differences for memory clinic 2 provided notable differences from memory clinic 1. The female control group identified less than two of the missing elements, which was almost identical to the finding of the female test group. Males scored slightly more correct answers than did the corresponding females, however the reduction in memory between the memory clinics decreased by similar levels.

Comparison of Results the Current Literature. The facts observed during the clinical tests indicate that those participants subjected to a stressful event immediately before completing the memory test scored lower than those who were not subjected to stress. Both males and females scored similarly, indicating that no differences exist in memory as a result of gender. There were some minor differences in the absolute numbers of memory retention, but the differences were minute and could just as easily be explained by chance. According to Salposky, the results found in this study are comparable with other literature, regarding the fact that cortisol can in fact interfere with the ability to thin and function (2000).

Limitations of the Study

The purpose of this study was to investigate the effects of physical and mental stress on both short and long term memory. The current study was comprised of twenty participants, which provided an adequate number for researchers to obtain a reasonable level of validity and reliability. However, the small sample size provided little additional data that could be analyzed using common statistical techniques. In addition, this study’s goal was to test the correlation of pulse rate, blood pressure, and salivary cortisol levels to experience stress. The literature suggests that age may have a significant role in experienced or perceived stress levels and subsequently affect those physiological elements that were being tested (Elzinga, 2005). The demographic characteristics collected for this study did not include a provision for age measurement. Likewise, it could be assumed that original fitness levels might play a significant role when physical stress is applied as a simulator for a stressful event. Original fitness levels were not calculated nor were variables such as sports activity or body mass index, or body fat levels. This type of data may have been useful for applying a consistent level of stress based on the original conditioning of the participant. Race and/or ethic background should also be included to ascertain if any differences exist among these groups. If a larger, more diverse sample were used, variables such as occupation should also be included. Most literature suggests that some occupations maintain a higher stress level on a consistent basis. For example, the stress experienced by police officers or air traffic controllers will probably vary considerably from that of an office worker or student. The last limitation also stems from the original size of the sample. The geographic location of participants may vary depending on the regions of the country from which they were drawn. Personality types or personal characteristics may also be included since some literature suggests that personality types differ in their perceived level of stress (Grant & Langan-Fox, 2007).

Suggestions For Additional Research

Subsequent studies for additional research into the physiological reactions to stress should include a larger number of participants. In order to achieve a confidence level of 95 percent the sample size should approximate 387 participants. This sample size would provide data that would allow a greater range of statistical calculations and a more intense level of analysis that would lend itself to stronger validity and reliability. A larger sample size would also allow the results to be generalized to the population. Secondly, any further research should include an increased number of demographic variables. For example, race, ethnicity, age, occupation, and income levels should be included to determine if a statistically significant difference exists among other variables. Fitness level, sports activity, body mass index, and body fat should also be measured in addition to a basic categorization of personality types.

Another suggestion for further research may include a series of memory clinic tests at selected intervals to determine at what point memory begins to decline after exposure to a stressful event. According to the current study, memory declined after a period of two weeks, however, the decline was not determined to be significant. Perhaps follow-up studies should be completed in two-week intervals until such time as the memory loss becomes significantly different from original results.

Different types of stress should also be examined in future studies to determine if memory retention as a result of physical stress differs from emotional stress. Participants could be shown images or interviews of traumatic events such as school shootings, war scenes or impoverished children. Eustress versus distress could also be examined. Three groups could be established. The control group not subjected to treatment, the second group exposed to a distressful event and the third groups exposed to positive or typically happy events such as a wedding, graduation, or birth of a loved one.

Blood sugar levels could be tested in addition to cortisol levels. In addition, individual data recorded to determine the percentage change experienced for participants. This type of data collection would yield far more significant results than taken from a group as a whole. The individual data could be collapsed as necessary provides meaningful results.

Conclusion

According to the results of this study, pulse rate and blood pressure are positively related to stress. However, stress does not significantly contribute to pulse rate and blood pressure. Cortisol levels do appear to have a greater impact when an individual is exposed to stressful event. The research indicates that cortisol is a positive release to the body by facilitating the release of hormones and neurotransmitters (Luipen, 2005). Persons exposed to short periods of stress exhibit an increased level of hormonal activity produced by the brain that can sharpen memory and energy levels. This type of activity is imperative for the body to prepare for the “fight or flight” response when exposed to danger. However, chronic exposure to stress can lead to an increased dependency for the demand of cortisol which can ultimately lead to long-term health issues such as hypertension and heart disease (National Institute of Health, 2002).

The results of this study indicate a correlation between Cortisol levels, stress and memory. Short-term memory appears to be affected at a more significant level than does long-term memory. Short-term memory or primary memory is responsible for the complex cognitive processes such as logic and decision making. Information is stored in short-term memory for up to about 30 minutes. This type of information is critical for understanding the implication for exposure to acute and chronic stress in particular occupations. How stress impacts decision making can be critical for those exposed to inherent imminent dangers such as gunfire or car crashes. If researchers are able to link the variables, this can ultimately lead to changes in training for military, law enforcement, or even automobile drivers.

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