Stephen Klassen, PhD

Assistant Professor, Kinesiology

Stephen Klassen

Office: WC 277
905 688 5550 x3383

My research program explores the neural communication strategies used by the brain to regulate the cardiovascular system and maintain human survival during physiological stressors such as physical exercise and maintaining the upright posture. My research program aims to discover:

1) the fundamental sympathetic neural messages directed towards the circulation to support human survival,

2) how the sympathetic neural messages that exist to keep us alive, ultimately fail, and contribute to human diseases,  and

3) the neuromodulatory effects of physical exercise. 

My laboratory uses microneurography to study the action potential discharge patterns of sympathetic nerves in humans.  

Dr. Klassen is currently recruiting undergraduate (honours thesis/directed readings/volunteers) and graduate students. Dr. Klassen strongly encourages individuals of underrepresented groups to apply.  

Stephen is also a research collaborator at Mayo Clinic, Rochester Minnesota. 

  • 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) 

Selected publications: 

Neurocirculatory regulation 

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. 

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.  

Shoemaker, J. K., Klassen, S.A., Badrov, M. B., Fadel, P.J. (2018). Fifty years of microneurography:  learning the language of the peripheral sympathetic nervous system in humans. Journal of Neurophysiology, 119(5): 1731-1744. 

Klassen, S.A., Moir, M.E., Usselman, C.W., Shoemaker, J.K. (2020). Heterogeneous baroreflex control of sympathetic action potential subpopulations in humans. The Journal of Physiology, 598 (10): 1881-1895. 

Klassen, S.A., Moir, M.E., Limberg, J.K., Baker, S.E., Nicholson, W.T., Curry T.B., Joyner, M.J., Shoemaker, J.K. (2019). Asynchronous action potential discharge in human muscle sympathetic nerve activity. American Journal of Physiology – Heart and Circulatory Physiology, 317(4): H754- H764.  

Klassen, S.A., Limberg, J.K., Baker, S.E., Nicholson W.T., Curry T.B., Joyner, M.J., Shoemaker, J.K.  (2018). The role of the paravertebral ganglia in human sympathetic neural discharge patterns.  Journal of Physiology, 596(18): 4497-4510. 

Klassen, S.A., De Abreu, S., Greaves, D.K., Kimmerly, D.K., Arbeille, P., Denise, P., Hughson, R.L., Normand, H., Shoemaker, J.K. (2018). Long-duration bed rest modifies sympathetic neural recruitment strategies in males and females. Journal of Applied Physiology, 124: 796-779. 

Klassen, S.A., Chirico, D., Dempster, K.S., Shoemaker, J.K., O’Leary, D.D. (2016). The role of aortic arch vascular mechanics in cardiovagal baroreflex sensitivity. American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, 311(1): R24-R32. 

Klassen, S.A., Chirico, D., O’Leary, D.D., Cairney, J., Wade, T.J. (2016). Linking systemic arterial stiffness among adolescents to adverse childhood experiences. Child abuse & neglect, 56:1-10 

Convalescent plasma therapy for COVID-19 

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,  J.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. 

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,  S.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. 

  • Human Physiology 
  • Cardiorespiratory & Environmental Physiology