Exercise, Reactivity and Health
Research interest is on the effect of exercise and reactivity on health. Reactivity, which is typically measured by assessing autonomic and metabolic response, relates to how the body responds to psychological and physical challenge. For example, research has shown that people at risk for hypertension and heart disease display exaggerated autonomic reactivity to psychological challenge. We examine how these abnormal autonomic responses lead to vascular abnormalities and disease. We also are interested in metabolic reactivity to physical challenge. For example, we have shown that high intensity spinning exercise results in significant fat loss in women. Thus, certain kinds of exercise result in fat loss whereas other forms do not. We are currently attempting to find out what fat loss mechanisms underlie this spinning-induced fat reduction. Impedance (cardiac output, cardiac contractility), beat-to-beat blood pressure, occlusion (muscle blood flow, vascular resistance), baroreceptor sensitivity (body and neck chambers), vagal sensitivity, pulse wave analysis (arterial stiffness), metabolic cart (O2 uptake), DEXA (body fat), and blood variables (e.g., catecholamines, glycerol, insulin, lactate, hemoglobin) are used in human subjects.
Current Projects
1. Vascular abnormalities in offspring of hypertensives
We are investigating whether the exaggerated skeletal blood flow response of young offspring of hypertensives causes vascular abnormalities in large, medium, and small arteries. As can be seen in Figure 1 we have found that these hyper-reactors compared to non-offspring controls exhibit reduced vasodilatory capacity (vascular abnormality in small resistance vessels).
 | Figure 1. Vasodilatory capacity of offspring of hypertensives is lower than that of control males (Peak FBF). The Stroop FBF indicates that offspring hypertensives display significantly greater blood flow to mental challenge. |
2. The ability of acute and chronic exercise to dampen skeletal blood flow hyper-reactivity and reverse arterial abnormalities of offspring of hypertensives
We have shown that acute aerobic exercise significantly reduces the hyper-vascular reactivity of offspring hypertensives. As can be seen in Figure 2 acute exercise normalizes the exaggerated skeletal blood flow response to mental challenge typically found in offspring of hypertensives. We will be conducting further studies to investigate the ability of chronic regular exercise to both reduce vascular reactivity and reverse vascular abnormality of the small resistance vessels of offspring hypertensives.
 | Figure 2. The effect of acute exercise on forearm blood flow during Stroop challenge in offspring of hypertensives (Hamer, Jones, & Boutcher, in review, Journal of Hypertension). |
3. Fat loss to high intensity intermittent exercise
We have shown that high intensity cycle spinning exercise (Figure 3), in contrast to steady state exercise, results in significant fat loss in young women. Thus, certain kinds of exercise result in fat loss whereas other forms do not. We are currently attempting to find out what fat loss mechanisms underlie this spinning-induced fat reduction.
 | Figure 3. An example of a subject performing high intensity cycle intermittent exercise. Blood samples are being collected from an indwelling catheter. |
Members of the Research Group
Associate Professor Steve Boutcher
Associate Professor Albert Avolio (Biomedical Engineering, UNSW)
Professor Don Chisholm (Garvan Institute)
Dr Yati Boutcher
Dr Maria Matuszek
Gail Trapp, PhD student
Young Park, PhD student
Nancy Dickman, PhD student
Sarah Dien, Masters student
Kai Huang, Honours student
Selected Publications
Hamer, M, Jones J, & Boutcher, SH. The effect of acute exercise on cardiovascular reactivity to mental challenge (In press - Journal of Hypertension)
Boutcher, S.H., & Hamer, M. (in press). Physical activity and cardiovascular reactivity. In E. Acevedo & P. Ekkekakis (Eds.), The Psychobiology of Exercise and Sport. Champaign: Human Kinetics.
Boutcher, Y.N., & Boutcher, S.H. Arm and leg blood flow characteristics of aerobically trained and untrained males. (In press– European Journal of Applied Physiology).
Hamer, M., & Boutcher, S.H. (2005). Stress reactivity and health - the impact of exercise and nutrition. In Kimberely V. Oxington (Ed.), Psychology of Stress, Nova Science publications.
Boutcher, S.H., McLaren, P., Cotton, & Nurhayati, Y. (2003). Stroke volume response of trained and untrained males during upright cycle ergometry. Canadian Journal of Applied Physiology, 28(1), 12-26.
Boutcher, Y.N., Hamer, M., & Boutcher, S.H. (2003). The effect of acute plasma volume expansion on venous capacitance. International Journal of Sports Medicine and Physical fitness, 43, (1), 105-110.
Hamer, M., Boutcher, Y.N., & Boutcher, S.H. (2003). The role of cardiopulmonary baroreceptors during the forearm vasodilatation response to mental stress in humans. Psychophysiology, 40, 249-253.
Franks, P., & Boutcher, S.H. (2003). Cardiovascular response to mental challenge in trained and untrained pre-teenage boys. Medicine and Science in Sports and Exercise, 35, 1429-1435.
Boutcher, S.H., Meyer, B., Graig, C., & Astheimer, L. (2003). Lipid and fibrinogen profiles in aerobically trained and untrained postmenopausal women. International Journal of Sports Medicine and Physical Fitness, 43(2): 231-235.
Hamer, M., Boutcher, Y.N., & Boutcher, S.H. (2002). Cardiovascular and renal reactivity to mental challenge in trained and untrained offspring hypertensives. Journal of Human Hypertension, 16, 319-326.
Boutcher, S.H., Nurhayati, Y., & McLaren, P. (2001). Cardiovascular response to mental challenge in trained and untrained older males. Medicine and Science in Sports and Exercise, 33, 659-664.