One common characteristic seen across the whole primate species is its competitive nature. Whether it’s competing to rise in the status hierarchy or competing in the Super Bowl or Stanley Cup Finals, primates as a whole engage in competition regularly. During the competitive stages, several physiological and psychological changes take place. The physiological changes have been examined by way of measuring blood pressure, heartbeat, respiration, and perspiration. Though these measures help in the understanding of the physiological responses of stress, researchers are now able to further understand the nature of stress from a hormonal standpoint. One popular method of measuring one’s physiological response to acute and chronic stress is by measuring salivary cortisol. This noninvasive method of analysis is especially useful in the athletic environment. Athletic competition is the preferred environment in which to study hormones and competition due to its highly organized and structured setting. This environment provides for clear rules and regulations and can also measure performance by way of wins/losses or other measures of individual performance. Understanding the underlying physiological and psychological responses to stress can have a significant effect on the way we view diseases such as heart disease, depression, anxiety, and even cancer. It has been well documented that chronic stress can have a debilitating effect on the immune system’s ability to fight off infection and disease. Therefore, with the increasing demands of life, it comes as no surprise that stress is now having a significant impact on the quality of life that one lives.
Hormonal Responses to Stress
Stress can be defined as a physical and/or psychological response to life experiences that may challenge or threaten us. Furthermore, stress can be experienced both subjectively through anxiety, fear, anger, and depression as well as physiologically. Stress can be brought on by several negative life events, such as a death in the family, divorce, or relocation, or even positive events such as a big job promotion or winning the lottery. When faced with a stressful situation, the body activates the sympathetic nervous system, which through the hypothalamus-pituitary-adrenal (HPA) axis mediates a wide range of adaptive functions. The stress response first begins in a deep structure within the brain known as the hypothalamus. The hypothalamus releases a protein known as the corticotopinreleasing factor (CRF), which then stimulates the pituitary gland. The pituitary gland then releases adrenocorticotropin hormone (ACTH), which, in turn, stimulates the release of cortisol from the adrenal gland. One way to measure HPA axis activation is by assessing cortisol levels. Cortisol has been found to be the most accepted marker of HPA axis activation. Furthermore, increased cortisol has been known to be an adaptive mechanism of the organism when stressed. Moderate increases in cortisol are known to prepare individuals for immediate or forthcoming action. This moderate increase enables one’s blood to move from the extremities to the large muscles that are used in physical activity, and it has also been shown to play a positive role in cognition and emotions. In contrast, larger increases in cortisol have been shown to decrease performance by interfering with cognitive processes and also by lowering testosterone levels. Furthermore, chronic stress has been shown to have a significant negative effect on one’s immune system.
Mazur’s Biosocial Model of Status
Allan Mazur’s biosocial model of status attempts to describe the hormonal changes that occur within one’s body during face-to-face interaction. According to Mazur, status ranks are allocated among individuals or members of a group through face-to-face interactions, and this process is seen across the primate species. Mazur’s model is based on the concept that primates, including humans, compete for status on a regular basis. During these “status” competitions, individuals attempt to “outstress” their competitor(s) through actions, nonverbal signs, or through verbal communication in humans. The winner(s) of the status contest assumes the higher or dominant rank, while the loser(s) assumes the lower rank. Studies have demonstrated that successful attempts to achieve or maintain status have led to increased levels of plasma or salivary testosterone levels. These studies suggest that rising or elevated testosterone levels are associated with assertive behavior, erect posture, strutting, and a general competitive nature. In contrast, diminished or depressed testosterone has been associated with submissive behavior, such as slumped posture and general acceptance of one’s lower rank. In addition to testosterone’s role in preparing one for competition, Mazur’s model also considers the relationship between competition and the stress experienced by individuals in response to or in anticipation of competition. Mazur’s research shows that in most primate species, the lower-ranked members can be described as “nervous” or “insecure” during their interactions. These primates would be expected to display a greater degree of anxiety symptoms. On the contrary, higher-ranked primates appear to have a “relaxed” and “confident” demeanor, enabling them to cope more effectively with stressful situations. Therefore, Mazur’s model suggests that winners would display the highest levels of testosterone and lowest levels of cortisol, while losers would tend to display lower levels of testosterone and higher levels of cortisol. This model lends support to the concept of a “winning streak” or a “losing streak.” Winners of competitions seem to gather a sort of momentum after consecutive successful competitions, and this concept is very important in athletic competition as well as in the competitive business world.
Athletic Competition and Stress
As can be imagined, there are various forms of competition that can be observed, with a wide variation amongst the primate species. One form of competition that has been found to provide valuable feedback on hormonal activity during competition is athletic competition. This form of competition is a great environment in which to measure cortisol activity because there is a clear set of rules and regulations and also there is normally an unambiguous outcome leading to a winner and loser. Therefore, scientists seek to gain insight into the workings of hormones prior to, during, and after athletic competition. One of the questions that researchers seek to answer is whether there is an anticipatory stress response to the upcoming athletic competition. Most of the research on this topic has found that there is indeed an anticipatory rise in salivary cortisol and testosterone prior to competition. Suay et al. studied judo fighters in an attempt to demonstrate the anticipatory rise in hormones. Comparing precompetition saliva samples to samples obtained on 8 resting days, Suay et al. did indeed find an anticipatory rise in both cortisol and testosterone. Furthermore, in a study investigating hormonal responses to competition among a group of university tennis players,
Booth et al. found a rise in testosterone and cortisol just prior to the competitive event. These studies suggest that anticipatory rises in cortisol and testosterone serve to ready the individual for the forthcoming competition.
Another area of interest is whether winning or losing has an effect on salivary cortisol and testosterone levels. In a study on human competition, Gladue et al. did report a significant increase in testosterone levels of winners as compared to losers. However, their results did not produce any significant differences in cortisol levels between winners and losers. In contrast to Mazur’s prediction of stress as proposed in his biosocial model of status, and perhaps counterintuitive, were the results from the studies of Elias and Suay et al. These studies both found significantly higher levels of salivary cortisol among the winners. This finding demonstrated that winners experienced significantly higher levels of stress than did the losers in the postcompetition phase.
Finally, important to the understanding of human competition is whether physical activity is the underlying cause of hormonal variation. Thus, can variations in salivary cortisol and testosterone be attributed to physical activity alone? Or is there a set of psychological variables that play an important role in the body’s physiological response to competition? To study this question, researchers can study or evaluate their participants in noncompetitive settings that require intense physical activity and in settings that are considered competitive and also require intense physical activity. Suay et al. found similar rises in cortisol and testosterone in both competitive and non-competitive physical activity settings. These results lend support to the idea that physical activity in both competitive and noncompetitive situations can significantly increase hormonal activity. Despite this evidence, other research has demonstrated that psychological variables have an important influence on the hormonal responses to competition. In a study investigating hormonal differences among NCAA hockey players, Putnam and Carré found no significant differences in salivary cortisol levels during a noncompetitive practice session. Although significant differences were not observed in this noncompetitive setting, the researchers did find statistically significant pre- to postgame rises in cortisol levels throughout the hockey season. This finding suggests that there is more than just physical activity that plays a role in the activation of the HPA axis, and there may be numerous psychological variables that can affect one’s physiological responses to athletic competition.
Stress and Disease
Although physiological responses to stress can be usefUl for short-term survival, excessive activation of the HPA axis can lead to disease and illness. For instance, high levels of cortisol can lead to a thinning of the lining of the stomach, which can lead to gastric ulcers. Furthermore, too much cortisol can also lead to thinning of one’s bones, which can increase the likelihood of osteoporosis and also bone fractures. Studies with monkeys have found a strong correlation between stress and heart disease. These studies have shown that monkeys undergoing chronic social stress related to changes in their hierarchies found a strong relationship between stress and cardiovascular disease. Chronic stress can also have a profound effect on one’s psychological well-being. It has been shown that excessive stress can lead to serious bouts of depression as well as anxiety disorders such as post-traumatic stress disorder. These disorders certainly have a psychological component; however, increases in HPA axis activation certainly contribute to the subjective experiences of the disorders. Furthermore, researchers have found that certain therapies geared toward reducing stress have had a positive impact on those treated. For instance, there have been numerous studies that have cited patients with compromised immune systems responding well to psychological intervention. These studies indicate that being able to cope with stress can have a profound effect on one’s immune system and his or her ability to fight off infection.
Research on the physiological and psychological effects of stress have enabled researchers to have a better understanding of how the body responds to stress. Furthermore, research on athletic competition and hormone responses to stress has led to mixed results. These results suggest that there is a multitude of psychological factors that play a central role in the activation of the HPA axis. Therefore, more research into psychological factors, such as self-esteem, self-confidence, mood, and personality may provide additional clues to the overall process of stress and competition.
References:
- Booth, A., Shelley, G., Mazur, A., Tharp, G., & Kittok, R. (1989). Testosterone and winning and losing in human competition. Hormones and Behavior, 23, 556-571.
- Bremmer, D. (2002). Does stress damage the brain? Understanding trauma-related disorders from a mind-body perspective. New York: Norton.
- Martens, R., Vealey, R., & Barton, D. (1990). Competitive anxiety in sport. Champaign, IL: Human Kinetics.
- Mazur, A. (1985). A biosocial model of status in face-to-face primate groups. Social Forces, 64, 377-402.
- Putnam, S., & Carré, J. (2005). Hormonal responses to competition in NCAA male hockey players. Manuscript in preparation.
- Salvador, A. (2005). Coping with competitive situations in humans. Neuroscience and Biobehavioral Reviews, 29, 195-205.
- Suay, F., Salvador, A., Gonzalez-Bono, E., Sanchis, C., Martinez, M., Simon, V. M., et al. (1999). Psychoneuroendocrinology, 24, 551-566.
