Most of us realize that our blood vessels play an important role in transporting blood to and from all of the tissues of our body. The human cardiovascular system is continually adapting to and co-coordinating the differing requirements of the body tissues and the energy demands of skeletal muscle alone are capable of changing 100 fold within seconds of the onset of a new task. Blood vessels are much more than static tubes for transporting blood. The structure and function of our blood vessels can adapt to challenges they are presented with and can change significantly in both health and disease. Two important features of our arteries (blood vessels which transport blood away from the heart) are how flexible (stiffness) they are and how much they can expand (dilate) when faced with the challenges of increasing pressure and/or flow. We know that these two features, stiffness and dilation, change with disease processes, aging, spinal cord injury and some exercise programs but we know very little about what regulates these changes. In my laboratory we have been studying the role that exercise, which can result in large pressure and flow challenges to the arteries, plays in changing arterial structure and function. We examine the responses of a variety of components of the cardiovascular system to exercise challenges in order to determine control mechanisms. The specific cardiovascular variables, which are central to this research, are blood pressure, blood flow and arterial stiffness, diameter, wall thickness and dilation. Objectives of my research program include examination of the impact of alterations in vessel stiffness and function on skeletal muscle blood flow responses both at rest, and during exercise. Our continuing studies will focus on the use of cutting edge ultrasound technology to examine blood vessel stiffness and regional blood flow in both healthy and clinical populations. The insight gained from these studies will assist in advancing the current basic knowledge of the cardiovascular system as well as identifying the effectiveness of exercise as an intervention in determining basic cardiovascular regulation and in improving health status and lifestyle.
Shenouda N*, Gillen JB, Gibala MJ, MacDonald MJ. Changes in brachial artery endothelial function and resting diameter with moderate-intensity continuous but not sprint interval training in sedentary men. J Appl Physiol (1985). 2017 May 25:jap.00058.2017. doi: 10.1152/japplphysiol.00058.2017. [Epub ahead of print] PMID:28546466
Au JS*, Valentino SE*, McPhee PG*, MacDonald MJ. Diastolic carotid artery longitudinal wall motion is sensitive to both aging and coronary artery disease status independent of arterial stiffness. Ultrasound Med Biol. 2017 Jun 16. pii: S0301-5629(17)30191-6. doi: 10.1016/j.ultrasmedbio.2017.04.026. [Epub ahead of print] PMID: 28629691
Shenouda N*, Proudfoot NA*, Currie KD*, Timmons BW, MacDonald MJ.Automated ultrasound edge-tracking software comparable to established semi-automated reference software for carotid intima thickness analysis. Clin Physiol Funct Imaging. 2017 Apr 26. doi: 10.1111/cpf.12428. [Epub ahead of print] PMID: 28444941
Cheng JL*, Au JS*, Guzman JC, Morillo CA, MacDonald MJ. Cardiovascular testing in patients with postural tachycardia syndrome and Ehlers-Danlos type III: authors’ response.
Clin Auton Res. 2017 Apr;27(2):119-120. doi: 10.1007/s10286-017-0402-1. Epub 2017 Feb 11. No abstract available. PMID: 28190177
Skelly LE, Gillen JB, MacInnis MJ, Martin BJ, Safdar A, Akhtar M, MacDonald MJ, Tarnopolsky MA, Gibala MJ Effect of sex on the acute skeletal muscle response to sprint interval exercise. Exp Physiol. 2017 Mar 1;102(3):354-365. doi: 10.1113/EP086118. Epub 2017 Jan 24. PMID: 28118678
Au JS*, Totosy de Zepetnek JO*, MacDonald MJ. Modelling perceived exertion during graded arm cycling exercise in spinal cord injury. Med Sci Sports Exerc. 2017 Jun;49(6):1190-1196. doi: 10.1249/MSS.0000000000001203. PMID: 28079704
Murrant CL, MacDonald MJ. Introduction to the Canadian Society for Exercise Physiology Symposium on Integrative Physiology Honouring Dr. Bengt Saltin: The use of Exercise to Study Integrative Physiology. Applied Physiology, Nutrition and Metabolism, 2017, 42(1), 99-99, 10.1139/apnm-2016-0546.
Cheng JL*, Au JA*, Guzman, JC, Morillo CA, MacDonald MJ. Cardiovascular profile in postural orthostatic tachycardia syndrome and Ehlers-Danlos syndrome type III. Clin Auton Res. 2017 Apr;27(2):113-116. doi: 10.1007/s10286-016-0392-4. Epub 2016 Dec 22. (ISI impact factor 1.257)
Cotie LM*,Currie KD*, McGill GM*, Cameron AJ*, McFadden AS*, Phillips SM, MacDonald MJ. Associations between measures of vascular structure and function and systemic circulating blood markers in humans. Physiol Rep. 2016 Sep; 4(18). Pii e12982. PMID: 27670408 (ISI Impact factor )
Au JS*, Oikawa SY, Morton RW, MacDonald MJ, Phillips SM. Arterial stiffness is reduced regardless of resistance training load in young men. Med Sci Sports Exerc. 2016 Sep 23. [Epub ahead of print] PMID: 27669442. (ISI impact factor 3.54)
Au, JS*, Ditor, DS, MacDonald, MJ and Stohr, EJ. Carotid artery longitudinal wall motion is associated with local blood velocity and left ventricular rotational, but not longitudinal mechanics. Physiol Rep. 2016 July; 4(14). Doi:10.14814/phy2.12872. PMID: 27440745.
Totosy de Zepetnek J.O., Doubelt I., Luijben T.A., MacDonald M.J. Cardiovascular health after spinal cord injury: a comprehensive examination of traditional and emerging risk factors. Critical Reviews in Physical Medicine and Rehabilitation, 2016; 28(3):101–119. DOI: 10.1615/CritRevPhysRehabilMed.2016018716.
Totosy de Zepetnek J.O.*, Au J.S., Hol A.T. Eng J.J., MacDonald M.J. Predicting peak
Currie K.D., A.A. Martin, P.J. Millar, N.D. Stone, B.W. Timmons, R.F. Dillenburg and M.J. MacDonald. Vascular and autonomic function in preschool aged children with congenital heart disease. Congenital Heart Disease. 2012 April 27. Epub ahead of print PMID 22537219.
Timmons, B.W., N. A. Proudfoot, M.J. MacDonald, S.R. Bray, J. Cairney. Health outcomes and physical activity in preschoolers (HOPP) study: rationale and design. BMC Public Health. Accepted April 4 2012.
Gibala, M.J., J.P. Little, M.J. MacDonald, J. A. Hawley. Physiological adaptations to low-volume, high intensity interval training in health and disease. J Physiol. 2012 Mar 1;590 (Pt5): 1077-84. Jan 30 [Epub ahead of print] PMID: 22289907.
Millar P.J., A. S. Levy, C. L. McGowan, N. McCartney, M.J. MacDonald. Isometric handgrip training lowers blood pressure and increases heart rate complexity in medicated hypertensive patients. Scand J. Med Sci Sports. 2012 Jan 20. [Epub ahead of print] PMID: 22260503.
Stuckey M.I., N. Tordi, L. Mourot, L.J. Gurr, M. Rakobowchuk, P.J. Millar, R. Toth, M.J. MacDonald, M.V. Kamath. Autonomic recovery following sprint exercise. Scand J Med. Sci. Sports. 2011 Apr 28 [Epub ahead of print] PMID 21535187.
Tang J.E., P.J. Lysecki, J.J. Manolakos, M.J. MacDonald, M.A.Tarnopolsky, S.M. Phillips. Bolus arginine supplementation affects neither muscle blood flow nor muscle protein synthesis at rest or after resistance exercise in young men. Journal of Nutrition. 2011 Feb; 141(2): 195-200. Epub Dec 29, 2010 PMID: 21191143.
Millar P.J., M.J. MacDonald and N. McCartney. Effects of isometric handgrip protocol on blood pressure and neurocardiac modulation. Int J Sports Med. 2011 Mar; 32(3):174-80. [Epub ahead of print Dec 16, 2010] PMID 21165806
Staples A.W., N.A. Burd, D.W.D. West, K.D. Currie, P.J.Atherton, D.R. Moore, M.J. Rennie, M.J. MacDonald, S.K. Baker, and S.M. Phillips. Carbohydrate does not augment exercise-induced protein accretion versus protein alone. Med. Sci. Sports and Exerc. Dec 1, 2010. [epub ahead of print] PMID: 21131864.
Rakobowchuk M., J. Crozier, E.I. Glover, N. Yasuda, S.M. Phillips, M.A. Tarnopolsky, M.J. MacDonald. Short-term unilateral leg immobilization alters peripheral but not central arterial structure and function in healthy young humans. Eur J Appl Phyiol. 2011 Feb; 111(2): 203-10. Epub 2010 Sept 18. PMID: 20852882.
Currie K.D., Proudfoot N.A., Timmons B.W., MacDonald M.J. Noninvasive measures of vascular health are reliable in preschool-aged children. Appl Physiol Nutr Metab. 2010 Aug; 35(4):512-517. PMID: 20725118.
Howarth K.R., Phillips S.M., MacDonald M.J., Richards D., Moreau N.A., Gibala M.J. Effect of glycogen availability on human skeletal muscle protein turnover during exercise and recovery. J Appl Physiol. 2010 Aug; 109(2):431-8. Epub 2010 May 20. PMID 20489032.
Cotie, L.M., C.L. Geurts, M.M. Adams, M.J. MacDonald. Leg skin temperature with body-weight supported treadmill and tilt-table standing training after spinal cord injury. Spinal Cord. 2011 Jan; 49(1):149-53. Epub 2010 May 18. PMID: 20479767.
Millar, P.J., M. Rakobowchuk, N.McCartney and M.J. MacDonald. Heart rate variability and nonlinear analysis of heart rate dynamics following single and multiple Wingate bouts. Appl. Physiol. Nutr. Metab. 2009 Oct; 34(5):875-883. PMID: 19935849.
McGowan, C.L., M.J. MacDonald. Commentaries on viewpoint: pick your Poiseuille: normalizing the shear stimulus in studies of flow-mediated dilation. J Appl. Physiol. 2009 Oct;107(4):1364; author reply 1366.
Millar, P.J., M.J. MacDonald, S.R. Bray, and N. McCartney. Isometric handgrip exercise improves acute neurocardiac regulation. Eur. J. Appl. Physiol. 2009 Nov; 107(5):509-15. Epub August 13 2009.?PMID: 19680681.
Millar P.J., M. Rakobowchuk, M.M. Adams, A.L. Hicks, N. McCartney, M.J. MacDonald. Effects of short-term training on heart rate dynamics in individuals with spinal cord injury. Autonomic Neuroscience. 2009 Oct5; 150(1-2):116-21. Epub Apr 28 2009. PMID: 19406691.
Millar, P.J., S.R.Bray, M.J. MacDonald, N. McCartney. Cardiovascular reactivity to psychophysiological stressors: Association with hypotensive effects of isometric handgrip training. Blood Pressure Monitoring Journal. 2009 Oct; 14(5):190-5. PMID: 19734781.
Rakobowchuk, M., M.I. Stuckey, P.J. Millar, L. Gurr and M.J. MacDonald. Effect of acute sprint interval exercise on central and peripheral artery distensibility in young healthy males. Eur. J. Appl. Physiol. 2009; 105: 787-795. Epub Jan 6 2009. PMID: 19125283.
MacDonald M.J. and K.D. Currie. Interval exercise is a path to good health, but how much, how often and for whom? Clinical Science (London). 2009 Feb; 116(4):315-316. Epub 2009, Jan 15. PMID: 19076061.
Rakobowchuk, M., S. Tanguay, K. Burgomaster, K. Howarth, M. Gibala and M.J. MacDonald. Sprint interval and traditional endurance training induce similar improvements in peripheral arterial stiffness and flow mediated dilation in healthy humans. Am J Physiol. Regul Integr Comp Physiol. 2008; 295: 236-242. Epub 2008, Apr 23.PMID: 18434437.
Millar, P.J., S.R. Bray, M.J. MacDonald, N. McCartney. The hypotensive effects of isometric handgrip training using an inexpensive spring handgrip training device. J Cardiopulmonary Rehabilitation and Prevention. 2008; 28(3):203-207 PMID: 18496321.
Burgomaster, K.A, K.R. Howarth, S.M. Phillips, M. Rakobowchuk, M.J. MacDonald, S.L. McGee, M.J. Gibala. Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. J. Physiol. 2008: 586(Pt 1):151-60. Epub 2007, Nov 8. PMID: 17991697.
Millar, P.J., S.R. Bray, C.L. McGowan, M.J. MacDonald, N. McCartney. Effects of isometric handgrip training among people medicated for hypertension; a multilevel analysis. Blood Press. Monit. 2007: 12 (5); 307-314. PMID: 17890969.
Poelkens, F., M. Rakobowchuk, K.A. Burgomaster, M.T.E. Hopman, S. M. Phillips and M.J. MacDonald. Effect of Unilateral Resistance Training on Arterial Compliance and Endothelial Function in Elderly Men. Applied Physiology, Nutrition and Metabolism. 2007 Aug;32(4):670-6.
Wilkenson, S.B., M.A. Tarnopolsky, M.J. MacDonald, J.R. MacDonald, D.A. Armstrong and S.M. Phillips. Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. AJCN April 2007, 85(4), 1031-40.
McGowan, C.L., A S. Levy, N. McCartney, and M. J. MacDonald. Isometric handgrip training does not improve flow-mediated dilation in persons with normal blood pressure. Clin Sci (Lond). 2007 June, 112(7): 403-9.
Klimstra, M.D., J. Dowling, J. Durkin, M. MacDonald. The Effect of Ultrasound Probe Orientation on the measurement of muscle architecture. Journal of Electromyography and Kinesiology. 2007, (17) 504-514. (ISI Impact Factor: 1.333)
McGowan, C.L., A. Visocchi , M. Faulkner, R. Verduyn, M. Rakobowchuk, A S. Levy, N. McCartney, and M. J. MacDonald. Isometric handgrip training improves local flow-mediated dilation in medicated hypertensives. European Journal of Applied Physiology 2007 Feb; 99(3):227-34. Epub 2006 Nov 15.
McGowan, C.L., A.S. Levy, P.J.Millar, J.C. Guzman, C.A.Morillo, N. McCartney, and M. J. MacDonald. Acute vascular responses to isometric handgrip exercise and the effects of training in persons medicated for hypertension. AJP- Heart and Circulation (Oct 2006); 291(4) H1797-802.