title: Effect of fitness on arm vascular and metabolic responses to upper body exercise.
abstract: We investigated arm perfusion and metabolism during upper body exercise. Eight average, fit subjects and seven rowers, mean +/- SE maximal oxygen uptake (VO2 max) 157 +/- 7 and 223 +/- 14 ml O2. kg(-0.73).min(-1), respectively, performed incremental arm cranking to exhaustion. Arm blood flow (ABF) was measured with thermodilution and arm muscle mass was estimated by dual-energy X-ray absorptiometry. During maximal arm cranking, pulmonary VO2 was approximately 45% higher in the rowers compared with the untrained subjects and peak ABF was 6.44 +/- 0.40 and 4.55 +/- 0.26 l/min, respectively (P < 0.05). The arm muscle mass for the rowers and the untrained subjects was 3.5 +/- 0.4 and 3.3 +/- 0.1 kg, i.e., arm perfusion was 1.9 +/- 0.2 and 1.4 +/- 0.1 l blood.kg(-1).min(-1), respectively (P < 0.05). The arteriovenous O2 difference was 156 +/- 7 and 120 +/- 8 ml/l, respectively, and arm VO2 was 0.98 +/- 0.08 and 0.60 +/- 0.04 l/min corresponding with 281 +/- 22 and 181 +/- 12 ml/kg, while arm O(2) diffusional conductance was 49.9 +/- 4.3 and 18.6 +/- 3.2 ml.min(-1).mmHg(-1), respectively (P < 0.05). Also, lactate release in the rowers was almost three times higher than in the untrained subjects (26.4 +/- 1.1 vs. 9.5 +/- 0.4 mmol/min, P < 0.05). The energy requirement of an approximately 50% larger arm work capacity after long-term arm endurance training is covered by an approximately 60% increase in aerobic metabolism and an almost tripling of the anaerobic capacity.
authors.affiliation: Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen 2100, Denmark. Stefanos.Volianitis@excite.com
authors.forename: S
authors.initials: S
authors.lastname: Volianitis
authors.forename: C C
authors.initials: CC
authors.lastname: Yoshiga
authors.forename: P
authors.initials: P
authors.lastname: Nissen
authors.forename: N H
authors.initials: NH
authors.lastname: Secher
mesh_terms: D000328:Adult; D001132:Arm / Q000098:blood supply* / Q000502:physiology*; D001158:Arteries; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D007866:Leg / Q000502:physiology; D008297:Male; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology*; D010809:Physical Fitness; D012039:Regional Blood Flow / Q000502:physiology; D014680:Veins
chemical_list: D019344:Lactic Acid; D010100:Oxygen