INTRODUCTION In our fast paced society stress is very common. Traffic, deadlines, money and many other life issues can trigger stress in our lives. Stress can disrupt the delicate homeostasis of our physical and mental well-being (Stress, 2006). In a stressful situation the body prepares for the fight or flight response by releasing stress hormones, such as cortisone and adrenaline (Stress, 2006). If the stress is prolonged or chronic, those chemicals can stay in the blood stream. Prolonged stress can lead to headaches, decreased immune system, fatigue, heart ailments, depression and many other physical and mental problems. It has long been thought that exercise can be a way to relieve stress. When one engages in physical activity there is certain chemical response the brain gives out. Endorphins are polypeptides that bind to the neuron-receptors in the brain and gives relief from stress (Carruthers, 2006). When they are released, endorphins can make one feel more positive and relaxed. This type of effect that exercise has on stress has been the topic of study for many years. One study on Exercise and Cardiovascular Stress Reactivity found that there was insufficient evidence to support a role for exercise in enhancing psychological function (de Geus, 2006). They found in doing their research that much of the research available was inconsistent and difficult to interpret because of all the factors that might affect the results. Inconsistencies such as individual difference factors, inadequate post exercise assessments, optimal exercise doses, and psychobiological plausible mechanisms make research in this area hard to interpret (Alderman, 2006). A different study, on the effects of a physical exercise intervention on subjective physical well-being found much of the same issues when gathering research. The research found was inconclusive (Sjogren et al 2006). In their own study they found that there was a significant increase in subjects physical well-being when they engaged in light resistance training (Sjogren, et al 2006). However, in other research conducted with rats on acute exercise and cardiovascular responses to stress in rats, it was found that there was no significant difference between trials conducted at resting and trials conducted at 30 minutes of exercise (Anderson & Overton, 1993). Another study on response of antioxidant defenses to oxidative stress induced by prolonged exercise, actually found that too much exercise was harmful to the body and its’ systems (Cases et al, 2006). The purpose of this study is to measure the effect that exercise has on stress levels. I hypothesize that subjects will rate their stress as decreased after engaging in two minutes of cardiovascular exercise.
The participants in this study were 16 students. Their ages ranged from 18 to 22. Some were selected through the online subject pool system where students can sign up for studies to earn extra credit. Others were selected at random. Each subject was informed of the fact that they may be asked to engage in physical activity and given a consent form.
The materials used were a stress survey retrieved from an online health quiz bank. The stopwatch function from a Nokia cell phone was used to keep track of exercise time.
First, the human subjects committee approved the study. Then the study was posted on the subject pool so that participants could sign up at a designated time. The participants were randomly assigned to groups. Group one was the control group, which did not engage in exercise. Group two was the experimental group, which did engage in exercise. Each subject was given a consent form that made him or her aware of the possibility that they may have to engage in physical activity. Then, each subject took a stress survey. Group two was told to engage in physical activity that consisted of jumping up and down and/ or jumping as if he or she were jumping rope. At the same time group one did nothing. After two minutes of physical activity, both groups took the stress survey again. Then, the number of yes’s and no’s were counted up for each subject’s before and after survey. A higher number of yes’s indicated a higher stress level.
RESULTS An independent-samples t- test was calculated comparing the average score of stress with people who engaged in exercise and those who did not. No significant difference was found (t (14)= .271, p>.05). The average of the decrease in stress of group two (m= -.87, sd= 1.80) was not significantly different from the average of the decrease in stress from group one (m= -1.12, sd=1.88).
DISCUSSION The results of this study were not significant. According to the data collected exercise did not have a significant effect on stress levels. The results of the subjects who engaged in physical activity showed no significant decrease in stress compared with the subjects who did not engage in any physical activity. These results are contrary to the results found by Sjogren et al. (2005). in the study on effects of a physical exercise intervention on subjective physical well-being . The results of this study were similar to the results that Anderson and Overton found when studying acute exercise and cardiovascular responses to stress in rats. No significant difference was found there either. Because of the results found by past studies and the lack of any concrete significance found by most of the studies conducted in this area, the results of my study were expected. The limitations of this study were that the sample used was very small. There were few participants that signed up on the online subject pool, and some chose not to attend. Another limitation was that the room used to test subjects was not equipped with enough space to accommodate a huge amount of physical activity. The subjects who were asked to engage in physical activity had limited room and had to limit their range of motion in order to not hit the other subjects engaging in physical activity. Also, there was only one testing room available for use. This meant that both groups, the exercise and no exercise, be tested at the same time. The fact that the exercise group was engaging in physical activity while the no exercise group watched them could have proved stressful on certain participants and increased their stress rating. The study was also limited because the age range of the students was very narrow. The subjects were all students from the age of 18 to 22. It is a possibility that most of these subjects are moderately physically fit, and may be less affected by two minutes of physical activity. Another limitation was that the subjects were tested about mid-semester. Traditionally, the end of semester is a much more stressful time due to final tests and projects. The survey used could have possibly limited the study because of the narrowness of the questions. Only yes or no answers were required, which does not take into account if a certain question does not apply to the subject. There are many different directions that future research in this are could take. For future research I would suggest that the amount of physical activity be extended to 20 or 30 minutes, allowing more time for endorphins to kick in. Another suggestion would be to have the subjects engage in a different type of physical activity. Hatha yoga, which requires a lot of long deep breaths or kickboxing, which uses powerful movement, may produce more significant results. Also, testing the subjects in a room with a lot of space could be more useful. Testing the two groups at separates times may also prove helpful in obtaining accurate results. If all the subjects being tested at a certain time are engaging in physical activity, it may make them more comfortable which, in turn, could affect how they rate their stress after physical activity. Another suggestion would be to use a different survey that requires answers to be rated on a scale. This would allow for a better rating of stress. It would also take into account questions that did not apply to the subject.
REFERENCES Alderman, B. (2006). Exercise and stress reactivity: Clarifying inconsistencies in literature. Psychophysiology, 58.Anderson, G.A., & Overton, J.M. (1993). Acute exercise and cardiovascular response to stress in rats. Physiology and Behavior, 639-643.Carruthers, C. (2006). Psychological effects of exercise [Electronic version]. Beginner Triathlete,1-6. Cases, N., Sureda, A., Maestre, I., Tauler, P., Aquilo, A., Cordova, A., Roche, E., Tur, J., & Pons, A. (2006). Responses to antioxidant defenses to oxidative stress induced by prolonged exercise. European Journal of Applied Physiology,263-269.De Geus, E.J. (2006). Exercise and cardiovascular stress reactivity: An update. Psychophysiology, 58.Sjogren, T., Nisson, K.J., Jarenpaa, S.K., Ojanen, M.T., Vanharanton, H., & Malkia, E.A.,(2006). Effects of a physical exercise intervention on subjective physical well-being, psychosocial functioning and general well-being among office workers: A cluster randomized-controlled cross-over design. Scandinavian Journal of Medicine and Science, 381-389. Stress (2006). Life positive[Electronic version]. 1-6.
APPENDIX Stress Test___1. Do you frequently neglect your diet? ___2. Do you frequently try to do everything yourself?___3. Do you frequently blow up easily?___4. Do you frequently seek unrealistic goals?___5. Do you frequently fail to see the humor in situations others find funny?___6. Do you frequently act rude?___7. Do you frequently make a “big deal” out of everything?___8. Do you frequently look to other people to make things happen?___9. Do you frequently complain you are disorganized?___10. Do you frequently avoid people whose ideas are different from your own?___11. Do you frequently keep everything inside?___12. Do you frequently neglect exercise? ___13. Do you frequently have few supportive relationships?___14.Do you frequently use sleeping pills and tranquilizers without a doctor’s approval?___15. Do you frequently get too little rest?___16. Do you frequently get angry when you are kept waiting?___17. Do you frequently ignore stress symptoms?___18. Do you frequently put things off until later?___19. Do you frequently think there is only one right way to do something?___20. Do you frequently fail to build relaxation time into your day?___21. Do you frequently gossip?___22. Do you frequently race through the day?___23. Do you frequently spend a lot of time complaining about the past?___24. Do you frequently fail to get a break from noise and crowds?