Dr James Fisher BSc (Hons), PhD

Dr James Fisher

School of Sport, Exercise and Rehabilitation Sciences
Reader in Cardiovascular Physiology

Contact details

Telephone
+44 (0)121 414 8011
Fax
+44 (0)121 414 4121
Email
j.p.fisher@bham.ac.uk
Address
School of Sport, Exercise and Rehabilitation Sciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
UK

Dr James Fisher is an Exercise Physiologist working in the field of human cardiovascular control. The focus of his laboratory is on the neural regulation of the heart and blood vessels in human health and disease.

Qualifications

  • BSc (Hons) Sport and Exercise Sciences. 1st class. (University of Birmingham)
  • PhD Sport and Exercise Sciences (University of Birmingham)

Biography

Following completion of his PhD in 2004, Dr James Fisher undertook a British Heart Foundation funded post-doctoral position which provided him the opportunity to work in the laboratories of Dr Niels Secher (University of Copenhagen, Denmark) and Dr Peter Raven (university of North Texas Health Science Center, Fort Worth, Texas, USA).

In 2006, Dr Fisher relocated to the USA where he worked in the laboratory of Dr Paul Fadel (University of Missouri, Columbia, Missouri) as an American Heart Association funded post-doctoral research fellow investigating the effects of age on arterial baroreflex function. In 2008 he was appointed as a Lecturer in the School of Sport and Exercise Sciences and maintains active collaborations with groups in the USA (Dr. Fadel, University of Missouri-Columbia), Denmark (Prof. Secher, University of Copenhagen), Japan (Prof. Ogoh, Toyo University) and Brazil (Dr. Vianna & Prof. Nobrega, Fluminense Federal University).

Dr Fisher regularly published in high impact physiology journals and has been the recipient several international research awards, including the Michael J. Brody Young Investigators Award (2008) and the Neural Control and Autonomic Regulation Section New Investigators Award (2013) from the American Physiological Society.

Teaching

  • BSc (Hons) Sport, Exercise and Rehabilitation Sciences. Module Organiser, Exercise Physiology, Level II.
  • BSc (Hons) Sport, Exercise and Rehabilitation Sciences. Lecturer, Testing in Sports and Exercise Sciences, Level II.
  • BSc (Hons) Sport, Exercise and Rehabilitation Sciences. Supervisor, Dissertation Research Project, Level III.
  • BMedSci (Hons) Lecturer, Biology of Ageing, Level IV.
  • BMedSci (Hons) Lecturer, CVS Integrative Mechanisms, Level IV.
  • MSc. Lecturer. Sport and Exercise Sciences.

Postgraduate supervision

Sultan Alsalahi is presently conducting a PhD in the area of autonomic neuroregulation of cardiovascular function.

Recent graduates include: Dr Alena Shantsila (2016), whose thesis examined the respiratory control of muscle sympathetic nerve activity in patients with high blood pressure. Dr Ahmed Adlan (2016), whose work investigated autonomic function in patients with rheumatoid arthritis. Dr Igor Braz (2016), who studied the influence of age and physical activity on cerebral blood flow, and Dr Clare McNulty (2016) who examined the associations between age, inflammation and physical activity.

Current MRes and MSci projects are presently being undertaken in the areas of cardiovascular rehabilitation, vascular function (training and the sympathetic nervous system) and cardiac autonomic regulation during exercise and environmental stress.

Research

Dr James Fisher’s research broadly concerns the neural control of the cardiovascular system at rest and during exercise in human health and disease. His main areas of interest are:

  • cardiovascular and cerebrovascular regulation during exercise
  • mechanisms underlying sympathetic neural hyperactivity in chronic disease.

This work is funded by the British Heart Foundation, Arthritis Research UK, Royal Society, NIHR and the BBSRC.

Examples of recent and active projects include:

  • Cerebral vasomotor regulation in atrial fibrillation.” British Heart Foundation PG/15/45/31579. Principal Investigator.
  • IMPRESS-AF: IMproved exercise tolerance in heart failure with PReserved Ejection fraction by Spironolactone on myocardial fibrosiS in Atrial Fibrillation.” NIHR Efficacy and Mechanism Evaluation, 12/10/19. Co-investigator.
  • Is altered respiratory-sympathetic coupling a pathogenic feature of human hypertension?”. British Heart Foundation, PG/11/41/28893. Principal Investigator.
  • Is central sympathetic overactivity a pathogenic feature of rheumatoid arthritis?”. Arthritis Research UK. Principal Investigator.

Research links

Other activities

Dr. James Fisher is a member of the Physiological Society (England) and the American Physiological Society, a Fellow of the Higher Education Academy (FHEA) and a member of the Experimental Physiology editorial board.

Publications

2016

Prodel E, Balanos GM, Braz ID, Nobrega ACL, Vianna LC & Fisher JP. (2016) Muscle metaboreflex and cerebral blood flow regulation in humans: implications for exercise with blood flow restriction. Am J Physiol Heart Circ Physiol. 310(9):H1201-9. doi: 10.1152/ajpheart.00894.2015.

Braz ID, Flück D, Lip GYH, Lundby C & Fisher JP. (2016) Impact of endurance exercise training on cerebral blood flow and cerebral vascular responsiveness to CO2 in young and older men. Scandinavian Journal of Medicine and Science in Sports. doi: 10.1111/sms.12674.

Bartlett DB, Fox O, McNulty CL,Greenwood H, Murphy L, Sapey E, Goodman M, Crabtree N, Thøgersen-Ntoumani C, Fisher JP, Wagenmakers AJ & Lord JM (2016). Habitual physical activity maintains neutrophil migratory dynamics in healthy older adults. Brain, Behaviour and Immunity. pii: S0889-1591(16)30044-7. doi: 10.1016/j.bbi.2016.02.024.

Prodel E, Fisher JP, Barbosa TC, Fernandes IA, Nobrega ACL & Vianna LC (2016). Relationship between aortic augmentation index and blood pressure during metaboreflex activation. Blood Press Monit. doi: 0.1097/MBP.0000000000000202.

Adlan AM, Paton JFR, Lip GY, Kitas GD & Fisher JP. (2016) Increased sympathetic nerve activity and reduced arterial baroreflex sensitivity in rheumatoid arthritis. J Physiol. doi: 10.1113/JP272944.

Shantsila E, Haynes RN, Calvert M, Fisher JP, Kirchhof P, Gill PS & Lip GYH. (2016) IMproved exercise tolerance in patients with PReserved Ejection fraction by Spironolactone on myocardial fibrosiS in Atrial Fibrillation: Rationale and design of the IMPRESS-AF randomized trial. BMJ Open. 6(10):e012241. doi: 10.1136/bmjopen-2016-012241.

Siebenmann C, Rasmussen P, Hug M, Keiser S, Flück D, Fisher JP, Hilty M, Maggiorini M & Lundby C. (2016) Parasympathetic withdrawal increases heart rate after two weeks at 3,454 m altitude. J Physiol. doi: 10.1113/JP273726.

Brindle RC, Phillips AC, Carroll D, Fisher JP & Ginty AT. (2016) Heart rate complexity: A novel approach to assessing cardiac stress reactivity. Psychophysiology. doi: 10.1111/psyp.12576.

Holwerda S, Restaino R, Fisher J & Fadel P. (2016) Augmented Skeletal Muscle Metaboreflex Activation in Patients with Type 2 Diabetes Mellitus. Am J Physiol Heart Circ Physiol. doi: 10.1152/ajpheart.00636.2015.

Turner, JE, Wadley AJ, Aldred S, Fisher JP, Bosch JA, Drayson MT & Campbell JP. (2016) Intensive Exercise Does Not Preferentially Mobilize Skin-Homing T Cells and NK Cells. Medicine & Science in Sports & Exercise. In press.

2015

Fisher JP, Young CN & Fadel PJ. (2015) Autonomic adjustments to exercise in humans. Compr Physiol. 5(2):475-512. doi: 10.1002/cphy.c140022.

Adlan AM, Panoulas VF, Smith JP, Fisher JP & Kitas GD. (2015) Relationship between QTc interval and inflammatory cytokines in rheumatoid arthritis. J Rheumatology. 42(3):421-8. doi: 10.3899/jrheum.140861.

Fisher JP, Fernandes IA, Barbosa TC, Prodel E, Coote JH, Nóbrega ACL & Vianna LC. (2015) Diving and Exercise: The interaction of trigeminal receptors and muscle metaboreceptors on muscle sympathetic nerve activity in humans. Am J Physiol Heart Circ Physiol. 308(5):H367-75. doi: 10.1152/ajpheart.00728.2014.

Wadley AJ, Chen YW, Bennett SJ, Lip GYH, Turner JE, Fisher JP & Aldred S. (2015) Monitoring changes in thioredoxin and over-oxidised peroxiredoxin in response to exercise in humans. Free Radic Res. 49(3):290-8. doi: 10.3109/10715762.2014.

Vianna LC, Fadel PJ, Secher NH & Fisher JP. (2015) A cholinergic contribution to the circulatory responses evoked at the onset of handgrip exercise in humans. Am J Physiol Regul Integr Comp Physiol. doi: 10.1152/ajpregu.00236.2014.

Cocks M, Shaw CS, Shepherd SO, Fisher JP, Ranasinghe A, Barker TA, Wagenmakers AJM. (2015) Sprint interval and moderate-intensity continuous training are equally effective at increasing endothelial eNOS/NADPHox protein ratio in skeletal muscle of obese males. J Physiol. doi: 10.1113/jphysiol.2014.285254.

Wadley AJ, Lip GYH, Fisher JP & Aldred S. (2015) Impact of low volume, high intensity interval training on markers of oxidative stress and inflammation in humans. J Sports Sci. 2015 Apr 27:1-9.

Fisher JP. (2015) Cardiac autonomic regulation during hypoxic exercise. Am J Physiol Heart Circ Physiol. 2015 May 1:ajpheart.00311.2015. doi: 10.1152/ajpheart.00311.2015.

Shantsila A, McIntyre DB, Lip GYH, Fadel PJ, Paton JFR, Pickering AE & Fisher JP. (2015) Influence of age on respiratory modulation of muscle sympathetic nerve activity, blood pressure and baroreflex function in humans. Exp Physiol. 100(9):1039-51. doi: 10.1113/EP085071.

Braz ID & Fisher JP. (2015) The impact of age on cerebral perfusion, oxygenation and metabolism during exercise in humans. J Physiol. doi: 10.1113/JP271081.

2014

Fisher JP. (2014) Autonomic control of the heart during exercise in humans: role of skeletal muscle afferents. Exp Physiol. 99(2):300-5. doi: 10.1113/expphysiol.2013.074377.

McNulty CL, Moody WE, Wagenmakers AJM, & Fisher JP. (2014) Muscle metaboreflex activation, central hemodynamics and cardiac function in humans. Applied Physiology, Nutrition, and Metabolism. 39(8):861-70. doi: 10.1139/apnm-2013-0414.

Adlan A, Lip GYH, Paton JFR, Kitas GD & Fisher JP. (2014) Autonomic function and rheumatoid arthritis: a systematic literature review. Seminars in Arthritis and Rheumatism. 44(3):283-304. doi: 10.1016/j.semarthrit.2014.06.003.

Flück D, Braz I, Keiser S, Hüppin F, Haider T, Hilty M, Fisher JP & Lundby C. (2014) Age, aerobic fitness and cerebral perfusion during exercise: role of carbon dioxide. Am J Physiol Heart Circ Physiol. 307(4):H515-23. doi: 10.1152/ajpheart.00177.2014.

Cocks M, Shaw CS, Shepherd SO, Fisher JP, Ranasinghe R, Barker TA, Tipton KD & Wagenmakers AJM. (2014) Effect of resistance training on microvascular density and eNOS content in skeletal muscle of sedentary men. Microcirculation. 21(8):738-46. doi: 10.1111/micc.12155.

Olsen ND, Van Lieshout JJ, Fisher JP, Seifert T, Nielsen HB & Secher NH. (2014) Case report: (Pre)syncopal symptoms provoked by a jugular venous siphon. Frontiers in Physiology. 5:317. doi: 10.3389/fphys.2014.00317.

Braz ID, Scott C, Simpson LM, Springham EL, Tan BWL, Balanos GM & Fisher JP. (2014) Influence of muscle metaboreceptor stimulation on middle cerebral artery blood velocity in humans. Exp Physiol. 99(11):1478-87. doi: 10.1113/expphysiol.2014.081687.

Eyre ELJ, Birch SL, Duncan MJ & Fisher JP. (2014) The influence of age and weight status on cardiac autonomic control in healthy children: a review. Auton Neurosci. Auton Neurosci. 186C:8-21. doi: 10.1016/j.autneu.2014.09.019.

2003-2013

Fisher JP. (2013) Autonomic control of the heart during exercise in humans: role of skeletal muscle afferents. Exp Physiol. In press.

Fisher JP, Adlan AM, Shantsila A, Secher JF, Sørensen H & Secher NH. (2013) Muscle metaboreflex and autonomic regulation of heart rate in humans. J Physiol. 591(Pt 15):3777-88. doi: 10.1113/jphysiol.2013.254722.

Ichikawa D, Miyazawa T, Horiuchi M, Kitama T, Fisher JP & Ogoh S. (2013) Relationship between aerobic endurance training and dynamic cerebral blood flow regulation in humans. Scand J Med Sci Sports. doi: 10.1111/sms.12082.

Eyre ELJ, Fisher JP, Smith EC, Wagenmakers AJM, & Matyka KA. (2013) Ethnicity and long term heart rate variability in children. Arch Dis Child. 98(4):292-8. doi: 10.1136/archdischild-2012-302266.

Hartwich D, Dear WE, Kirtley LA, Taylor SM, Waterfall JL & Fisher JP. (2013) Influence of menstrual cycle phase on muscle metaboreflex control of cardiac baroreflex sensitivity, heart rate and blood pressure in young women. Exp Physiol. 98(1):220-32. doi: 10.1113/expphysiol.2012.066498. 

Fisher JP, Hartwich D, Seifert T, Olesen ND, McNulty CL, Nielsen HB, van Lieshout JJ, & Secher NH. (2013) Cerebral perfusion, oxygenation and metabolism during exercise in young and elderly individuals. J Physiol. 591(Pt 7):1859-70. doi: 10.1113/jphysiol.2012.244905.

Cocks M, Shaw CS, Shepherd SO, Fisher JP, Ranasinghe AM, Barker T, Tipton KT, & Wagenmakers AJM. (2013) High intensity interval and traditional endurance training are equally effective in improving muscle microvascular structure and eNOS content in sedentary males. J Physiol. 591(Pt 3):641-56. doi: 10.1113/jphysiol.2012.239566.

Adlan AM, Lip GYH, Fadel PJ, & Fisher JP. (2012) Sympathetic nerve activity during non-sustained ventricular tachycardia in chronic heart failure. Int J Cardiol. doi:pii: S0167-5273(12)01521-5.10.1016/j.ijcard.2012.10.088.

Ogoh S, Hirasawa A & Fisher JP. (2012) Arterial baroreflex regulation of cerebral blood flow in humans. J Phys Fitness Sports Med, 1(4): 001-006.

Deo SH, Fisher JP, Vianna LC, Kim A, Chockalingam A, Zimmerman MC, Zucker IH & Fadel PJ. (2012) Statin therapy lowers muscle sympathetic nerve activity and oxidative stress in patients with heart failure. Am J Physiol Heart Circ Physiol. 303(3):H377-85. 

Sato K, Fisher JP, Seifert T, Overgaard M, Secher NH, & Ogoh. (2012) Blood flow and dynamic autoregulation in internal carotid and vertebral arteries during orthostatic stress. Exp Physiol. 97(12):1272-80. doi: 10.1113/expphysiol.2012.064774. 

Fisher JP, Kim A, Hartwich, & Fadel PJ. (2012) New insights into the effects of age and sex on arterial baroreflex function at rest and during dynamic exercise in humans. Auton Neurosci. 172(1-2):13-22. doi: 10.1016/j.autneu.2012.10.013.

Sugawara J, Komine K, Miyazawa T, Imai T, Fisher JP & Ogoh. (2012) Impact of chronic exercise training on the blood pressure response to orthostatic stimulation. J Appl Physiol. 112(11):1891-6.

Kim A, Deo S, Fisher JP & Fadel PJ. (2012) Effect of sex and ovarian hormones on carotid baroreflex resetting and function during dynamic exercise in humans. J Appl Physiol. 112(8):1361-71.

Fisher JP & Paton JFR. (2011). The sympathetic nervous system and blood pressure in humans: Implications for hypertension. J Human Hypertension. doi: 10.1038/jhh.2011.66.

Fisher JP & Secher NH. (2011) The brain at work. J Physiol. 15;589(Pt 18):4405.

Kim A, Young CN, Deo S, Fisher JP & Fadel PJ. (2011) Sex differences in carotid baroreflex control of arterial blood pressure in humans: Relative contribution of cardiac output and total vascular conductance. Am J Physiol Heart Circ Physiol. 301(6):H2454-65.

Hartwich D, Dear WE, Waterfall JL & & Fisher JP. (2011) Effect of muscle metaboreflex activation on spontaneous cardiac baroreflex sensitivity during exercise in humans. J Physiol. 15;589(Pt 24):6157-71.

Ogoh S, Sato K, Fisher JP, Siefert T, Ouergaard M & Secher NH. (2011) The effect of phenylephrine on arterial and venous cerebral blood flow in healthy subjects. Clin Physiol Func Imaging. 31(6):445-51.

Kiilerich K, Jørgensen SR, Biensøe RS, Fisher JP, Iversen N, Van Hall G, Wojtaszewski JFP, Saltin B, Lundby C, Calbet JAL & Pilegaard H. (2011) Exercise-induced pyruvate dehydrogenase activation is not affected by seven days of bed rest. J Appl Physiol. 111(3):751-7.

Fisher JP, Seifert T, Hartwich D, Young C, Secher NH & Fadel PJ. (2010) Autonomic control of heart rate by metabolically sensitive skeletal muscle afferents in humans. J Physiol (Lond). 588(Pt 7):1117-27. See accompanying Editorial Perspective: Kaufman MP. (2010) Metaboreflex control of the heart. J Physiol (Lond). 588(Pt 7):1037-8.

Fisher JP & Fadel PJ. (2010) Therapeutic strategies for targeting excessive central sympathetic activation in human hypertension. Exp Physiol. 95(5):572-80. See accompanying Editorial Perspective: Paton JF, Raizada MK. (2010) Neurogenic hypertension. Exp Physiol. 95(5):569-71.

Fisher JP, Seifert T, Hartwich D, Young C, Secher NH & Fadel PJ. (2010) Reply: Muscle metaboreflex and exercise heart rate: insights from studies in subjects with and without heart failure. J Physiol (Lond). 588(14): 2681.

Campbell R, Fisher JP, Sharman JE, McDonnell BJ & Frenneaux MP. (2010) Contribution of nitric oxide to the blood pressure and arterial responses to exercise in humans. J Human Hypertension. In press.

Seifert T, Fisher JP, Young C, Hartwich D, Ogoh S, Raven PB, Fadel PJ & Secher NH. (2010) Is a cholinergic mechanism involved in regulation of cerebral perfusion during exercise in humans? Exp Physiol. 95(10):1016-25. See accompanying Editorial Perspective: Truijen J, van Lieshout JJ. (2010) Parasympathetic control of blood flow to the activated human brain. Exp Physiol. 95(10):980-1.

Fisher JP, Kim A, Young CN & Fadel PJ. (2010) Alterations in carotid baroreflex control of arterial blood pressure at rest and during dynamic exercise in aging humans. Am J Physiol Regul Integr Comp Physiol. 299(5):R1241-7.

Hartwich D, Fowler KL, Wynn LJ & Fisher JP. (2010) Differential responses to sympathetic stimulation in the cerebral and brachial circulations during rhythmic handgrip exercise in humans. Exp Physiol. 95(11):1089-97.

Fisher JP, Kim A, Young CN, Ogoh O, Raven PB, Secher NH & Fadel PJ. (2009) Influence of ageing on carotid-baroreflex peak response latency in humans. J Physiol (Lond). In press.

Young CN, Fisher JP, Gallagher KM, Whaley-Connel A, Chaudhary K, Victor RG, Thomas GD & Fadel PJ. (2009) Inhibition of nitric oxide synthase evokes central sympatho-excitation in healthy humans. J Physiol (Lond). In press.

Vianna LC, Araujo CG & Fisher JP. (2009) Influence of central command and muscle afferent activation on anterior cerebral artery blood velocity responses to calf exercise in humans. J Appl Physiol. In press.

Ogoh S, Fisher JP, Young C, Raven PB & Fadel PJ. (2009) Transfer function characteristics of the neural and peripheral arterial baroreflex arc at rest and during post-isometric exercise muscle ischemia in humans. Am J Physiol Heart Circ Physiol. 296(5):H1416-24.

Fisher JP, Young C & Fadel PJ. (2009) Central Sympathetic Overactivity: Maladies and mechanisms. Auton Neurosci. 15;148(1-2):5-15.

Fisher JP, Ogoh S, Ahmed A & Fadel PJ. (2009) Can spontaneous indices of cardiac-baroreflex sensitivity detect age-related differences in baroreflex function during dynamic exercise? Exp Physiol. 94(4):447-58.

Fisher JP, S Ogoh, PB Raven & PJ Fadel. (2008) The influence of age on the regulation of cerebral blood flow during dynamic exercise in humans. J Appl Physiol. 105(1):266-73.

Fisher JP, Young C & Fadel PJ. (2008) Muscle metaboreflex control of carotid-cardiac baroreflex in humans. Am J Physiol Heart Circ Physiol. 294(5):H2296-304.Young CN, Fisher JP, Fadel PJ. (2008) The ups and downs of assessing baroreflex function. J Physiol (Lond). 586(5):1209-11.

Ogoh S, JP Fisher, PB Raven & PJ Fadel. (2007) Arterial baroreflex control of muscle sympathetic nerve activity in the transition from rest to steady-state dynamic exercise in humans. AJP (Heart Circ Physiol). 293(4):H2202-9.

Fisher JP, S Ogoh, CN Young, DM Keller & PJ Fadel. (2007) Exercise intensity influences cardiac baroreflex function at the onset of isometric exercise in humans. J Appl Physiol, 103(3):941-7.

Fisher JP, S Ogoh, A Ahmed, MR Aro, D Gute & PJ Fadel. (2007) Influence of age on cardiac baroreflex function during dynamic exercise in humans. AJP (Heart Circ Physiol), 293: H777-H783.

Ogoh S, JP Fisher, PJ Fadel & PB Raven. (2007) Increases in central blood volume modulate carotid baroreflex resetting during dynamic exercise in humans. J Physiol, 581.1: 405-18.

Ogoh S, Fisher JP, Purkayastha S, Dawson EA, Fadel PJ, White MJ, Zhang R, Secher NH & Raven PB. (2007) Regulation of middle cerebral artery blood velocity during recovery from dynamic exercise in humans. J Appl Physiol. 102:713-21.

Fisher JP, Ogoh S, Dawson EA, Fadel PJ, Secher NH, Raven PB & White MJ. (2006) Cardiac and vasomotor components of the carotid baroreflex control of arterial blood pressure during isometric exercise in humans. J Physiol (Lond). 572: 869-880.

Ogoh S, Fisher JP, Dawson EA, White MJ, Secher NH & Raven PB. (2005) Autonomic nervous system influence on arterial baroreflex control of heart rate during exercise in humans. J Physiol (Lond). 566 (Pt 2): 599-611.

Fisher JP, Sander M, MacDonald I & White MJ. (2005) Decreased MSNA does not explain increased vascular conductance during contralateral isometric exercise in humans. Exp Physiol. 90 (3): 377-82.

Fisher JP, Bell MPD & White MJ. (2005) Cardiovascular responses to human calf muscle stretch during varying levels of muscle metaboreflex activation. Exp Physiol. 90 (5):773-81.

Fisher JP & White MJ. (2004) Muscle afferent contributions to the cardiovascular response to isometric exercise. Exp Physiol. 89 (6): 639-646

JP Fisher, S Ogoh, EA Dawson, PJ Fadel, NH Secher, PB Raven, MJ White. 2004. Cardiac and vasomotor components of the carotid baroreflex control of aterial blood pressure during isometric exercise in humans, Journal of Physiology, 572, 869-880.

JP Fisher, S Ogoh, A Ahmed, MR Aro, D Gute, PJ Fadel. 2004. Influence of age on cardiac baroreflex function during dynamic exercise in humans, American Journal of Physiology (Consolidated), 293, H777-H783.

Carrington CA, Fisher JP, Davies MK & White MJ. (2004) Muscle afferent inputs to cardiovascular control during isometric exercise vary with muscle group in patients with chronic heart failure. Clin Sci (Lond). 107 (2): 197-204.

Fisher JP & White MJ. (2003) The time course and direction of lower limb vascular conductance changes during voluntary and electrically evoked isometric exercise of the contralateral calf muscle in man. J Physiol (Lond). 546: 315-323.