title: Central and peripheral hemodynamics in exercising humans: leg vs arm exercise.
abstract: In humans, arm exercise is known to elicit larger increases in arterial blood pressure (BP) than leg exercise. However, the precise regulation of regional vascular conductances (VC) for the distribution of cardiac output with exercise intensity remains unknown. Hemodynamic responses were assessed during incremental upright arm cranking (AC) and leg pedalling (LP) to exhaustion (Wmax) in nine males. Systemic VC, peak cardiac output (Qpeak) (indocyanine green) and stroke volume (SV) were 18%, 23%, and 20% lower during AC than LP. The mean BP, the rate-pressure product and the associated myocardial oxygen demand were 22%, 12%, and 14% higher, respectively, during maximal AC than LP. Trunk VC was reduced to similar values at Wmax. At Wmax, muscle mass-normalized VC and fractional O2 extraction were lower in the arm than the leg muscles. However, this was compensated for during AC by raising perfusion pressure to increase O2 delivery, allowing a similar peak VO2 per kg of muscle mass in both extremities. In summary, despite a lower Qpeak during arm cranking the cardiovascular strain is much higher than during leg pedalling. The adjustments of regional conductances during incremental exercise to exhaustion depend mostly on the relative intensity of exercise and are limb-specific.
authors.affiliation: Department of Physical Education and Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Canary Islands, Spain.|The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.
authors.forename: J A L
authors.initials: JA
authors.lastname: Calbet
authors.affiliation: The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.|Centre for Sports Medicine and Human Performance, Brunel University London, Uxbridge, UK.
authors.forename: J
authors.initials: J
authors.lastname: González-Alonso
authors.affiliation: The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.|Centre for Healthy Ageing, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J W
authors.initials: JW
authors.lastname: Helge
authors.affiliation: The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Søndergaard
authors.affiliation: The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Munch-Andersen
authors.affiliation: The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.
authors.forename: B
authors.initials: B
authors.lastname: Saltin
authors.affiliation: The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen N, Denmark.|School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Boushel
mesh_terms: D000328:Adult; D001132:Arm / Q000098:blood supply / Q000502:physiology*; D062186:Arterial Pressure; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006321:Heart / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D005082:Physical Exertion / Q000502:physiology*; D012039:Regional Blood Flow; D013318:Stroke Volume; D014655:Vascular Resistance; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Cardiac output; VO
  2max; arm cranking; arterial blood pressure; fatigue; oxygen extraction; perfor-mance