Dr. Laura Klein, associate professor of biobehavioral health, who led the study, explains that our fight or flight response produces not only the familiar dry mouth, pounding heart and sweaty palms that accompany a stressful experience but also body chemistry changes that could result in health consequences.
Using doses of caffeine equivalent to drinking one to four cups of coffee and an intense arithmetic test as stressors, Klein and her colleagues found a rise in the amount of alpha amylase, an enzyme secreted by the salivary glands, in the healthy young men who participated in the study.
The results verified, based on performance, that a moderate dose of caffeine 200 mg or about the amount in two cups of coffee increased task performance and that doubling the amount of caffeine brings performance back down. The results also suggest that alpha amylase, which can be detected and measured via a new non invasive saliva test, provides a window on the biochemistry of the response not offered by cortisol alone which is commonly used to study the health consequences of stress.
The Penn State groups' results were detailed in a paper, "Effects of Caffeine and Stress on Salivary Alpha-Amylase in Young Men: A Salivary Biomarker of Sympathetic Activity," presented Thursday, March 2, at the annual meeting of American Psychosomatic Association Society in Denver, Colo. The authors are Klein; Courtney A. Whetzel and Jeanette M. Bennett, doctoral candidates in biobehavioral health; Dr. Frank E. Ritter, associate professor of information sciences and technology, psychology and computer science and engineering; and Dr. Douglas A. Granger, associate professor of biobehavioral health and human development and family studies.