• Sympathetic neural regulation of the human circulation in health and disease
• Reflex and feedforward neural regulation of cardiovascular function
• Interactive effects of age and biological sex on neurocirculatory regulation
• Integrative human physiology

• American Physiological Society (APS)
• International Society for Autonomic Neuroscience (ISAN)
• Canadian Society for Exercise Physiology (CSEP)

• New Investigator Award (American Physiological Society, Neural Control and Autonomic Regulation Section)
• Early Career Research and Creativity Award (Brock University)

Selected Publications Regarding Neurocirculatory regulation:

Klassen, S. A. (2026). Emerging concepts in baroreflex regulation of action potential subpopulations in human muscle sympathetic nerve activity. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 331(2). Link to article

Klassen, S.A., Shoemaker, J.K. (2020). Action potential subpopulations within human muscle sympathetic nerve activity: discharge properties and governing mechanisms. Autonomic Neuroscience: Basic and Clinical, 230. Link to article

Klassen, S.A., Joyner, M.J., Baker, S.E. (2021). The impact of ageing and sex on sympathetic neurocirculatory regulation. Seminars in Cell and Developmental Biology, 116: 72-81. Link to article

Klassen, S. A., Limberg, J. K., Harvey, R. E., Wiggins, C. C., Spafford, J. E., Iannarelli, N. J., & Baker, S. E. (2024). Human sympathetic neuronal discharge and recruitment patterns regulate neuropeptide Y bioavailability. American Journal of Physiology-Heart and Circulatory Physiology, 327(6), H1599-H1605. Link to article

Iannarelli, N. J., Spafford, J. E., Lynn, C. M., Cheung, S. S., O’Leary, D. D., Shoemaker, J. K., & Klassen, S. A. (2026). Sympathetic action potential synchronicity and blood pressure regulation in healthy young adults. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 331(3).Link to article

Lynn, C. M., Iannarelli, N. J., Spafford, J. E., O’Leary, D. D., Cheung, S. S., & Klassen, S. A. (2026). Trigeminal reflex regulation of sympathetic neural communication strategies in human muscle sympathetic nerve activity. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 330(4), R356-R367. Link to article

Iannarelli, N. J., Lynn, C. M., Spafford, J. E., Sattin, M. N., O’Leary, D. D., Cheung, S. S., & Klassen, S. A. (2026). Baroreflex regulation of sympathetic neuronal discharge during large, rapid changes in blood pressure caused by ventricular bigeminy and sinus pause. Journal of Applied Physiology, 140(1), 208-219. Link to article

Spafford, J. E., Limberg, J. K., Harvey, R. E., Wiggins, C. C., Iannarelli, N. J., Senefeld, J. W., … & Klassen, S. A. (2025). The role of α2-adrenergic mechanisms in sympathetic baroreflex control of human blood pressure. American Journal of Physiology-Heart and Circulatory Physiology, 329(5), H1229-H1243. Link to article

Iannarelli, N. J., Spafford, J. E., Greaves, D. K., Denise, P., Normand, H., Hughson, R. L., Klassen, S. A., & Shoemaker, J. K. (2025). Long-duration head-down bed rest alters human sympathetic neurocirculatory regulation. Journal of Applied Physiology, 139(5), 1246-1259. Link to article.

Wallace, P. J., Lidstone, S., Nowlan, J. G., Ljubanovich, J., McKinlay, B. J., Klassen, S. A., & Cheung, S. S. (2025). Individuals with persisting post‐concussion symptoms with physiological subtype demonstrate altered cardiovascular and autonomic responses to face cooling. Experimental Physiology. Link to article

Klassen, S. A., Limberg, J. K., Harvey, R. E., Wiggins, C. C., Iannarelli, N. J., Senefeld, J. W., & Baker, S. E. (2024). Central α2‐adrenergic mechanisms regulate human sympathetic neuronal discharge strategies. The Journal of physiology, 602(16), 4053-4071. Link to article

Selected Publications Regarding Convalescent plasma therapy for COVID-19:

Klassen, S. A., & Senefeld, J. W. (2024). Evidence for the Efficacy of COVID-19 Convalescent Plasma. Convalescent Plasma and Other Antibody Therapies for Infectious Diseases: Lessons learned from COVID-19 and Future Prospects, 99-117. Link to article

Klassen, S.A., Senefeld, J.W., Johnson, P.W., Carter, R.E., Wiggins, C.C., Shoham S.,  Grossman, B.J., Henderson, J.P., Musser, J., Salazar, E., Hartman, W.R., Bouvier, N.M., Liu, T.H., Pirofski, L., Baker, S.E., van Helmond, N., Wright, R.S., Fairweather, D., Bruno, K.A., Wang,  Z., Paneth, N.S., Casadevall, A., Joyner, M.J. (2021). The Effect of Convalescent Plasma Therapy  on COVID-19 Patient Mortality: Systematic Review and Meta-analysis. Mayo Clinic Proceedings, 96(5): 1262-1275. Link to article

Joyner, M.J., Carter, R.E., Senefeld, J.W., Klassen, S.A., Mills J.R., Johnson P.W., Theel, E.S.,  Wiggins, C.C., Bruno, K.A.,Klompas, A.M., Lesser, E.R., Kunze, K.L., Sexton, M.A., Diaz Soto, C., Baker, S.E., Shepherd, J.R.A., van Helmond, N., Verdun, N.C., Marks, P., van Buskirk, C.M.,  Winters, J.L., Stubbs, J.R., Rea, R.F., Hodge, D.O., Herasevich, V., Whelan, E.R., Clayburn, A.J.,  Larson, K.F., Ripoll, J.G., Andersen, K.J., Buras, M.R., Vogt, M.N.P., Dennis, J.J., Regimbal, R.J.,  Bauer, P.R., Blair, J.E., Paneth, N.S., Fairweather, D., Wright, R.S., Casadevall, A. (2021).  Convalescent plasma antibody levels and the risk of death from Covid-19. New England Journal of Medicine, 384 (11): 1015-1027. Link to article

• Human Integrative Physiology
• Cardiorespiratory Exercise Physiology in Health and Disease
• Human Integrative Neurocirculatory Regulation

Dr. Klassen is currently recruiting undergraduate students including students interested in honours theses, directed reading, and volunteer opportunities. Dr. Klassen strongly encourages individuals of underrepresented groups to apply.  Please email [email protected] with a statement of interest, a copy of grades, and an updated resume/curriculum vitae.

Dr. Klassen is currently recruiting MSc and PhD students as well as Post-Doctoral Fellows. Dr. Klassen strongly encourages individuals of underrepresented groups to apply.  Please email [email protected] with a statement of interest, a copy of grades, and an updated resume/curriculum vitae.