title: End-exercise ΔHHb/ΔVO2and post-exercise local oxygen availability in relation to exercise intensity.
abstract: Increased local blood supply is thought to be one of the mechanisms underlying oxidative adaptations to interval training regimes. The relationship of exercise intensity with local blood supply and oxygen availability has not been sufficiently evaluated yet. The aim of this study was to examine the effect of six different intensities (40-90% peak oxygen uptake, VO2peak) on relative changes in oxygenated, deoxygenated and total haemoglobin (ΔO2Hb, ΔHHb, ΔTHb) concentration after exercise as well as end-exercise ΔHHb/ΔVO2as a marker for microvascular O2distribution. Seventeen male subjects performed an experimental protocol consisting of 3 min cycling bouts at each exercise intensity in randomized order, separated by 5 min rests. ΔO2Hb and ΔHHb were monitored with near-infrared spectroscopy of the vastus lateralis muscle, and VO2was assessed. ΔHHb/ΔVO2increased significantly from 40% to 60% VO2peak and decreased from 60% to 90% VO2peak. Post-exercise ΔTHb and ΔO2Hb showed an overshoot in relation to pre-exercise values, which was equal after 40-60% VO2peakand rose significantly thereafter. A plateau was reached following exercise at ≥80% VO2peak. The results suggest that there is an increasing mismatch of local O2delivery and utilization during exercise up to 60% VO2peak. This insufficient local O2distribution is progressively improved above that intensity. Further, exercise intensities of ≥80% VO2peakinduce highest local post-exercise O2availability. These effects are likely due to improved microvascular perfusion by enhanced vasodilation, which could be mediated by higher lactate production and the accompanying acidosis.
authors.affiliation: Center for Teaching and Learning, Technische Universität München, München, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Stöcker
authors.affiliation: Center for Teaching and Learning, Technische Universität München, München, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Von Oldershausen
authors.affiliation: Department of Biomechanics in Sports, Technische Universität München, München, Germany.
authors.forename: F K
authors.initials: FK
authors.lastname: Paternoster
authors.affiliation: Department for Preventive Pediatrics, Technische Universität München, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schulz
authors.affiliation: Department for Preventive Pediatrics, Technische Universität München, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Oberhoffer
mesh_terms: D000293:Adolescent; D000328:Adult; D001642:Bicycling; D015415:Biomarkers / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D064368:Healthy Volunteers; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008833:Microcirculation; D009119:Muscle Contraction; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000098:blood supply* / Q000378:metabolism*; D011897:Random Allocation; D012039:Regional Blood Flow; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D014664:Vasodilation; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen
keywords: exercise intensity; hyperaemia; muscle oxygenation; near-infrared spectroscopy; post-exercise muscle perfusion; prior exercise