Impaired Lactate Exchange and Removal Abilities after Supramaximal Exercise in Humans

2015 ◽  
pp. 140-161 ◽  
Author(s):  
S. Oyono-Enguelle ◽  
H. Freund ◽  
J. Lonsdorfer ◽  
A. Pape
Keyword(s):  
Supramaximal Exercise ◽  
Lactate Exchange ◽  
Exercise In Humans

Restrictions in Locomotor Skeletal Muscle Perfusion, Oxygen Supply and VO2 During Supramaximal Exercise in Humans

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S60
Author(s):  
Stefan P. Mortensen ◽  
Ellen A. Dawson ◽  
Rasmus Damsgaard ◽  
Niels H. Secher ◽  
José González-Alonso ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Supply ◽  
Supramaximal Exercise ◽  
Muscle Perfusion ◽  
Exercise In Humans

Importance of pH regulation and lactate/H+ transport capacity for work production during supramaximal exercise in humans

2007 ◽  
Vol 102 (5) ◽  
pp. 1936-1944 ◽  
Author(s):  
Laurent Messonnier ◽  
Michael Kristensen ◽  
Carsten Juel ◽  
Christian Denis
Keyword(s):  
Proton Transport ◽  
Buffer Capacity ◽  
Ph Regulation ◽  
Work Capacity ◽  
Monocarboxylate Transporter ◽  
Supramaximal Exercise ◽  
Muscle Lactate ◽  
Muscle Ph ◽  
Work Production ◽  
Exercise In Humans

We examine the influence of the cytosolic and membrane-bound contents of carbonic anhydrase (CA; CAII, CAIII, CAIV, and CAXIV) and the muscle content of proteins involved in lactate and proton transport [monocarboxylate transporter (MCT) 1, MCT4, and Na+/H+ exchanger 1 (NHE1)] on work capacity during supramaximal exercise. Eight healthy, sedentary subjects performed exercises at 120% of the work rate corresponding to maximal oxygen uptake (Ẇmax) until exhaustion in placebo (Con) and metabolic alkalosis (Alk) conditions. The total (Wtot) and supramaximal work performed (Wsup) was measured. Muscle biopsies were obtained before and immediately after standardized exercises (se) at 120% Ẇmax in both conditions to determine the content of the targeted proteins, the decrease in muscle pH (ΔpHm), and the muscle lactate accumulation ([Lac]m) per joule of Wsup (ΔpHm/Wsup-se and Δ[Lac]m/Wsup-se, respectively) and the dynamic buffer capacity. In Con, Wsup was negatively correlated with ΔpHm/Wsup-se, positively correlated with Δ[Lac]m/Wsup-se and MCT1, and tended to be positively correlated with MCT4 and NHE1. CAII + CAIII were correlated positively with ΔpHm/Wsup-se and negatively with Δ[Lac]m/Wsup-se, while CAIV was positively related to Wtot. The changes in Wsup with Alk were correlated positively with those in dynamic buffer capacity and negatively with Wsup in Con. Performance improvement with Alk was greater in subjects having a low content of proteins involved in pH regulation and lactate/proton transport. These results show the importance of pH regulating mechanisms and lactate/proton transport on work capacity and the role of the CA to delay decrease in pHm and accumulation in [Lac]m during supramaximal exercise in humans.

Oronasal partitioning of ventilation during exercise in humans

1991 ◽  
Vol 71 (2) ◽  
pp. 546-551 ◽  
Author(s):  
J. R. Wheatley ◽  
T. C. Amis ◽  
L. A. Engel
Keyword(s):  
Upper Airway ◽  
Normal Subjects ◽  
Face Mask ◽  
Inspiratory Flow ◽  
Mean Flow ◽  
Total Flow ◽  
Progressive Exercise ◽  
Expiratory Flow ◽  
Exercise In Humans

The partitioning of oronasal breathing was studied in five normal subjects during progressive exercise. Subjects performed three to five identical runs, each consisting of four 1-min work periods at increments of 50 W. Nasal and oral airflow were measured simultaneously using a partitioned face mask both during and for 4 min after exercise. Total mean flows were the sum of nasal and oral flows. At a total mean inspiratory flow of 2 l/s, the nasal fraction of total flow was 0.36 +/- 0.04 (SE) and decreased by 6 +/- 3% between total flows of 1.5 and 2.5 l/s. Throughout exercise, the nasal fraction of total mean inspiratory flow did not differ from that of total expiratory flow and was similar to that of total mean inspiratory flow during the postexercise period at a corresponding total mean flow (both P greater than 0.02). The results show that oronasal flow partitioning is not directly due to the exercise itself but is related to the level of ventilation and is uninfluenced by the direction of upper airway flow (i.e., inspiratory vs. expiratory). These findings suggest tightly controlled modulation of the relative resistances of the oral and/or nasal pathways.

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