title: Impaired cerebral blood flow and oxygenation during exercise in type 2 diabetic patients.
abstract: Endothelial vascular function and capacity to increase cardiac output during exercise are impaired in patients with type 2 diabetes (T2DM). We tested the hypothesis that the increase in cerebral blood flow (CBF) during exercise is also blunted and, therefore, that cerebral oxygenation becomes affected and perceived exertion increased in T2DM patients. We quantified cerebrovascular besides systemic hemodynamic responses to incremental ergometer cycling exercise in eight male T2DM and seven control subjects. CBF was assessed from the Fick equation and by transcranial Doppler-determined middle cerebral artery blood flow velocity. Cerebral oxygenation and metabolism were evaluated from the arterial-to-venous differences for oxygen, glucose, and lactate. Blood pressure was comparable during exercise between the two groups. However, the partial pressure of arterial carbon dioxide was lower at higher workloads in T2DM patients and their work capacity and increase in cardiac output were only ~80% of that established in the control subjects. CBF and cerebral oxygenation were reduced during exercise in T2DM patients (P < 0.05), and they expressed a higher rating of perceived exertion (P < 0.05). In contrast, CBF increased ~20% during exercise in the control group while the brain uptake of lactate and glucose was similar in the two groups. In conclusion, these results suggest that impaired CBF and oxygenation responses to exercise in T2DM patients may relate to limited ability to increase cardiac output and to reduced vasodilatory capacity and could contribute to their high perceived exertion.
authors.affiliation: Department of Internal Medicine, AMC Center for Heart Failure Research Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands Department of Anatomy, Embryology & Physiology, AMC Center for Heart Failure Research Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands Laboratory for Clinical Cardiovascular Physiology, AMC Center for Heart Failure Research Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Yu-Sok
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Center University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Seifert
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Center University of Copenhagen, Copenhagen, Denmark.
authors.forename: Patrice
authors.identifier: http://orcid.org/0000-0002-6254-5044
authors.initials: P
authors.lastname: Brassard
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Center University of Copenhagen, Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Rasmussen
authors.affiliation: Department of Endocrinology, Rigshospitalet University of Copenhagen, Copenhagen, Denmark.
authors.forename: Allan
authors.initials: A
authors.lastname: Vaag
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Center University of Copenhagen, Copenhagen, Denmark.
authors.forename: Henning B
authors.initials: HB
authors.lastname: Nielsen
authors.affiliation: Department of Anesthesia, The Copenhagen Muscle Research Center University of Copenhagen, Copenhagen, Denmark.
authors.forename: Niels H
authors.initials: NH
authors.lastname: Secher
authors.affiliation: Department of Internal Medicine, AMC Center for Heart Failure Research Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands Department of Anatomy, Embryology & Physiology, AMC Center for Heart Failure Research Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands Laboratory for Clinical Cardiovascular Physiology, AMC Center for Heart Failure Research Academic Medical Center University of Amsterdam, Amsterdam, The Netherlands MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences University of Nottingham Medical School Queen's Medical Centre, Nottingham, UK j.j.vanlieshout@amc.uva.nl johannes.vanlieshout@nottingham.ac.uk.
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: van Lieshout
keywords: Cardiac output; cerebral autoregulation; cerebral circulation; cerebral perfusion; cerebrovascular conductance