Studies of married couples, soccer and hockey teams focus on brain's response to stress
New research presented at International Congress of NeuroendocrinologyPITTSBURGH– Men's World Cup Soccer: More than 700 players – their countries' heroes – representing 32 teams, each vying to claim one of sports most coveted titles. It may take more than good coaching and a strong squad to win. Who takes all may be decided by the team with the most testosterone. Indeed, research has shown that levels are elevated in men during competitive sports. Now, a new study reported by Portuguese researchers at the 6th International Congress of Neuroendocrinology (ICN 2006) shows increases in the male hormone give female soccer players the winning edge as well.
But what if your opponent is not a sports rival but instead your spouse? A team of Swiss and American investigators report at ICN 2006 that a nasal spray with the hormone oxytocin can reduce stress during marital conflict. ICN 2006 takes place June 19 – 22 at the David L. Lawrence Convention Center in downtown Pittsburgh.
Summaries of the studies' findings and two others, one involving Canadian hockey players and the other looking at how the brain is affected by chronic stress, follow:
Testosterone fuels competition in women
Female and male athletes have more in common than just the desire to compete: Both produce more testosterone in the heat of competition, making greater amounts of the hormone when they win.
Researchers from the Institute for Applied Psychology (ISPA) in Lisbon, Portugal, collected saliva samples from players in the Portugal Female Soccer League championship game before and after the match. According to Rui Oliveira, Ph.D., associate professor, who led the study, the women produced increased levels of the hormone in anticipation of a match, a finding previously associated only with men. Moreover, as has been observed by other studies on their male counterparts, the female athletes' testosterone levels remained high after winning a contest, while levels returned to baseline in the losers. There was no significant difference in testosterone levels among team members on either squad when they were tested on a non-game day.
The study also found that fluctuations in testosterone mirrored changes in mood, with winners reporting positive mood changes and the losers feeling foul. The investigators believe these results indicate that mood changes likely play a key role in moderating the endocrine system's response to social challenges, such as a high-stakes game.
Testosterone gives teams the hormone-field advantage
In sports, the home team typically wins more often than it loses. Most would assume this is so because the visitors are worn down by the stress of travel and spending the night in unfamiliar hotels. According to a study involving amateur athletes, such advantages may not be due to the creature comforts that come with sleeping in one's own bed as much as they may relate to a very basic need for protecting territory.
Investigators looking into the "home advantage" phenomenon studied an ice hockey team over the course of a season, measuring testosterone and cortisol levels before and after each game. Wins were associated with greater pre- to post-game testosterone but pre-game testosterone levels were found to be even higher before home contests, suggesting the hormone surge may provide impetus for defending one's territory. As a dog defends its yard, these hockey players are driven to defend home ice.
According to Justin Carré, a Ph.D. candidate in the department of psychology at Brock University, in St. Catharines, Ontario, Canada, levels of cortisol, a hormone associated with stress, also were higher in team members when playing at home, indicating that skating in front of family and friends engendered pressure not felt on the road. Yet, pre-game self-confidence also was higher when the team played in their home venue, with a strong correlation between pre-game self-confidence and performance.
Oxytocin, the "hormone of love," may help take the stress out of marital spats
To determine if the hormone oxytocin can reduce stress during tense social interactions or conflict, a team of investigators studied subjects one would assume have plenty of first-hand experience: married couples and those in long-term relationships. Who more appropriate to evaluate whether giving oxytocin – nicknamed the "hormone of love" – can soften the emotional and physical baggage that comes with "discussing" whose turn it is to take out the trash?
Beate Ditzen, Ph.D., a postdoctoral fellow in the department of psychiatry and behavioral sciences from Emory University in Atlanta, and colleagues from the University of Fribourg and the University of Zurich, conducted a double-blind, placebo-controlled trial involving 50 heterosexual couples who the researchers guided into mock arguments by choosing with the couple a topic frequently discussed and unresolved in the relationship. The couples were then asked to discuss the topic during a 10-minute period and arguments were video-taped. Prior to provocation, half the couples received oxytocin via nasal spray, while the others received a placebo intranasally. From saliva samples, the team monitored production of a stress hormone called cortisol. Standard questionnaires were used to measure personality traits and document how participants perceived the quality and social support of their relationships.
The preliminary analyses suggest that cortisol levels, which normally are elevated under stressful situations, were significantly lower in the oxytocin-treated couples than in the control group, providing evidence that oxytocin helps keep stress in check during conflict. Being able to curb such stress, which can be persistent in nature, could have long-term health benefits as well.
Stress, the Brain and You
Looking for a stress-free life? Forget it. Stressors are everywhere, be they real or imagined, physical or psychological, large or small, animal or mineral. There's just no hiding from those things that can stress us out. So, it's a good thing the brain has a good handle on how to respond, at least in circumstances that require more than just fast thinking.
In an acute situation, the brain helps to protect us from threat by sending orders to the adrenal glands to release hormones such as cortisol, which mobilize bodily reserves to help meet the challenge. Systems like blood pressure and blood sugar are geared up, while other processes are temporarily shut down. It's an efficient and effective approach for dealing with the occasional tense situation, like running for the bus or meeting your tax deadline, but it takes a toll on our bodies just the same. Even more exhaustive is chronic stress. Over prolonged periods, high levels of cortisol associated with chronic stress can overwhelm the body. Indeed, chronic stress is implicated in the development or exacerbation of depression, post-traumatic stress disorder, dementia and heart disease and it can seriously impair the immune system's ability to stave off infection. Finding the mechanisms that control chronic responses to stress is critical for understanding and treating stress-related diseases, says James P. Herman, Ph.D., a professor of psychiatry who studies the neurobiology of stress at the University of Cincinnati. His studies suggest there is a different brain circuitry involved in chronic stress than is used for acute stress response. Moreover, he's found in animal studies that chronic stress can have long-term consequences for how the brain responds to or anticipates future encounters.
Held in a different part of the world every four years under the auspices of the International Neuroendocrine Federation, this year's congress – Bridging Neuroscience and Endocrinology – is being sponsored by the American Neuroendocrine Society and the University of Pittsburgh School of Medicine. The first full day of the program, June 20, is being held in conjunction with the 10th Annual Meeting of the Society for Behavioral Neuroendocrinology.
Formerly the International Society of Neuroendocrinology, the International Neuroendocrine Federation consists of six member societies and seven regional groups, representing all parts of the world. The federation's president is John A. Russell, MBChB, Ph.D., chair of neuroendocrinology, University of Edinburgh. The chair of the ICN 2006 scientific program is Iain J. Clarke, Ph.D., professorial fellow in the department of physiology at Monash University in Australia. Tony Plant, Ph.D., professor of cell biology and physiology and director of the Center for Research in Reproductive Physiology, University of Pittsburgh School of Medicine, is chair of the local organizing committee.
NOTE TO EDITORS: The researchers will discuss their work during a briefing, "Winners and Losers: Conflict, Competition and Stress," Tuesday, June 20 at 10 a.m., that will be moderated by John Russell, MBChB, Ph.D., chair of neuroendocrinology, University of Edinburgh, Scotland, and president of the International Neuroendocrine Federation. All briefings take place in rooms 306-307 of the David L. Lawrence Convention Center, downtown Pittsburgh. Reporters may participate via telephone conference call by dialing 800-860-2442 (from within the U.S.) or 866-519-5086 (from Canada). From other countries, call 001-412-858-4600. To be connected to the briefing you must reference ICN 2006. More information about the meeting and the schedule of briefings are available at http://newsbureau.upmc.com/ICN2006. The press room hours are 8 a.m. to 6 p.m., Tuesday, June 20 through Thursday, June 22; Press room staff may be reached during this time at (412) 325-6080. Otherwise, please call the UPMC News Bureau at (412) 647-3555 or Lisa Rossi at (412) 916-3315 (cell).
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