scholarly journals Functional support for a novel mechanism that enhances tissue oxygen extraction in a teleost fish

2019 ◽  
Vol 286 (1903) ◽  
pp. 20190339 ◽  
Author(s):  
T. S. Harter ◽  
F. S. Zanuzzo ◽  
C. T. Supuran ◽  
A. K. Gamperl ◽  
C. J. Brauner
Keyword(s):  
Maximal Exercise ◽  
Submaximal Exercise ◽  
Spawning Migration ◽  
Exercise Recovery ◽  
Teleost Fishes ◽  
Tissue Oxygen ◽  
Athletic Ability ◽  
Proton Production ◽  
Hypoxic Acclimation

A successful spawning migration in salmon depends on their athletic ability, and thus on efficient cardiovascular oxygen (O 2 ) transport. Most teleost fishes have highly pH-sensitive haemoglobins (Hb) that can release large amounts of O 2 when the blood is acidified at the tissues. We hypothesized that plasma-accessible carbonic anhydrase (paCA; the enzyme that catalyses proton production from CO 2 ) is required to acidify the blood at the tissues and promote tissue O 2 extraction. Previous studies have reported an elevated tissue O 2 extraction in hypoxia-acclimated teleosts that may also be facilitated by paCA. Thus, to create experimental contrasts in tissue O 2 extraction, Atlantic salmon were acclimated to normoxia or hypoxia (40% air saturation for more than six weeks), and the role of paCA in enhancing tissue O 2 extraction was tested by inhibiting paCA at rest and during submaximal exercise. Our results show that: (i) in both acclimation groups, the inhibition of paCA increased cardiac output by one-third, indicating a role of paCA in promoting tissue O 2 extraction during exercise, recovery and at rest; (ii) the recruitment of paCA was plastic and increased following hypoxic acclimation; and (iii) maximal exercise performance in salmon, and thus a successful spawning migration, may not be possible without paCA.

Measurements of metabolic rate in rats: a comparison of techniques

1988 ◽  
Vol 65 (2) ◽  
pp. 964-970 ◽  
Author(s):  
T. I. Musch ◽  
A. Bruno ◽  
G. E. Bradford ◽  
A. Vayonis ◽  
R. L. Moore
Keyword(s):  
Metabolic Rate ◽  
Maximal Exercise ◽  
Ambient Air ◽  
Open Circuit ◽  
Submaximal Exercise ◽  
Co2 Production ◽  
Arterial Blood ◽  
In Series ◽  
Series Of Experiments ◽  
Four Levels

Two different open-circuit techniques of measuring metabolic rate were examined in rats at rest and during exercise. With one technique ambient air was drawn through a tightly fitting mask that was secured to the rat's head, whereas with the other technique the rat was placed into and ambient air was drawn through a Plexiglas box. Two series of experiments were performed. In series I, two groups were studied that consisted of rats that had received myocardial infarctions produced by coronary arterial ligations and rats that had received sham operations. In this series of experiments O2 uptake (VO2) and CO2 production (VCO2) were measured at rest, during four levels of submaximal exercise, and during maximal treadmill exercise in the same group of rats by use of both techniques in random order. VO2, VCO2, and the calculated respiratory exchange ratio (R) were similar at rest, during the highest level of submaximal exercise (20% grade, 37 m/min), and during maximal exercise; however, VO2 and VCO2 were significantly lower with the metabolic box technique compared with the mask technique during the three lowest work loads (5% grade, 19 m/min; 10% grade, 24 m/min; and 15% grade, 31 m/min). These differences appeared to be associated with a change in gait produced when the mask was worn. In series II, the arterial blood gas and acid-base responses to both submaximal and maximal exercise were measured using both techniques in a group of instrumented rats that had a catheter placed into the right carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise recovery above and below anaerobic threshold following maximal work

1981 ◽  
Vol 51 (4) ◽  
pp. 840-844 ◽  
Author(s):  
B. A. Stamford ◽  
A. Weltman ◽  
R. Moffatt ◽  
S. Sady
Keyword(s):  
Blood Lactate ◽  
Anaerobic Threshold ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Base Line ◽  
Exercise Recovery ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Individual Subject

The purpose of this study was to determine the effects of resting and exercise recovery above [70% of maximum O2 uptake (VO2 max)] and below [40% of VO2 max] anaerobic threshold (AT) on blood lactate disappearance following maximal exercise. Blood lactate concentrations at rest (0.9 mM) and during exercise at 40% (1.3 mM) and 70% (3.5 mM) of VO2 max without preceding maximal exercise were determined on separate occasions and represented base lines for each condition. The rate of blood lactate disappearance from peak values was ascertained from single-component exponential curves fit for each individual subject for each condition using both the determined and resting base lines. When determined base lines were utilized, there were no significant differences in curve parameters between the 40 and 70% of VO2 max recoveries, and both were significantly different from the resting recovery. When a resting base line (0.9 mM) was utilized for all conditions, 40% of VO2 max demonstrated a significantly faster half time than either 70% of VO2 max or resting recovery. No differences were found between 70% of VO2 max and resting recovery. It was concluded that interpretation of the effectiveness of exercise recovery above and below AT with respect to blood lactate disappearance is influenced by the base-line blood lactate concentration utilized in the calculation of exponential half times.

scholarly journals Dichloroacetate Therapy Attenuates the Blood Lactate Response to Submaximal Exercise in Patients with Defects in Mitochondrial Energy Metabolism

2004 ◽  
Vol 89 (4) ◽  
pp. 1733-1738 ◽  
Author(s):  
G. E. Duncan ◽  
L. A. Perkins ◽  
D. W. Theriaque ◽  
R. E. Neiberger ◽  
P. W. Stacpoole
Keyword(s):  
Blood Lactate ◽  
Chronic Treatment ◽  
Maximal Exercise ◽  
Submaximal Exercise ◽  
Alternate Treatment ◽  
Mitochondrial Energy Metabolism ◽  
Chronic Effects ◽  
Acute And Chronic Treatment ◽  
Acute And Chronic Effects ◽  
Maximal Exercise Capacity

Abstract We determined acute and chronic effects of dichloroacetate (DCA) on maximal (MAX) and submaximal (SUB) exercise responses in patients with abnormal mitochondrial energetics. Subjects (n = 9) completed a MAX treadmill bout 1 h after ingesting 25 mg/kg DCA or placebo (PL). A 15-min SUB bout was completed the next day while receiving the same treatment. After a 1-d washout, MAX and SUB were repeated while receiving the alternate treatment (acute). Gas exchange and heart rate were measured throughout all tests. Blood lactate (Bla) was measured 0, 3, and 10 min after MAX, and 5, 10, and 15 min during SUB. MAX and SUB were repeated after 3 months of daily DCA or PL. After a 2-wk washout, a final MAX and SUB were completed after 3 months of alternate treatment (chronic). Average Bla during SUB was lower (P < 0.05) during both acute (1.99 ± 1.10 vs. 2.49 ± 1.52 mmol/liter) and chronic (1.71 ± 1.37 vs. 2.39 ± 1.32 mmol/liter) DCA vs. PL despite similar exercise intensities between conditions (∼75 and 70% maximal exercise capacity during acute and chronic treatment). Thus, although DCA does not alter MAX responses, acute and chronic DCA attenuate the Bla response to moderate exercise in patients with abnormal mitochondrial energetics.

scholarly journals The Potential Role of Genetic Markers in Talent Identification and Athlete Assessment in Elite Sport

Sports ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 88 ◽  
Author(s):  
Ysabel Jacob ◽  
Tania Spiteri ◽  
Nicolas Hart ◽  
Ryan Anderton
Keyword(s):  
Genetic Markers ◽  
Skill Acquisition ◽  
Athletic Performance ◽  
Potential Role ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Talent Identification ◽  
Motor Skill Acquisition ◽  
Athletic Ability

In elite sporting codes, the identification and promotion of future athletes into specialised talent pathways is heavily reliant upon objective physical, technical, and tactical characteristics, in addition to subjective coach assessments. Despite the availability of a plethora of assessments, the dependence on subjective forms of identification remain commonplace in most sporting codes. More recently, genetic markers, including several single nucleotide polymorphisms (SNPs), have been correlated with enhanced aerobic capacity, strength, and an overall increase in athletic ability. In this review, we discuss the effects of a number of candidate genes on athletic performance, across single-skilled and multifaceted sporting codes, and propose additional markers for the identification of motor skill acquisition and learning. While displaying some inconsistencies, both the ACE and ACTN3 polymorphisms appear to be more prevalent in strength and endurance sporting teams, and have been found to correlate to physical assessments. More recently, a number of polymorphisms reportedly correlating to athlete performance have gained attention, however inconsistent research design and varying sports make it difficult to ascertain the relevance to the wider sporting population. In elucidating the role of genetic markers in athleticism, existing talent identification protocols may significantly improve—and ultimately enable—targeted resourcing in junior talent pathways.

Comparison of Linear and Nonlinear HRV Dynamics Across Exercise Intensities After Menopause

2020 ◽  
Vol 28 (1) ◽  
pp. 149-154
Author(s):  
Julia C. Orri ◽  
Elizabeth M. Hughes ◽  
Deepa G. Mistry ◽  
Antone Scala
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Exercise Training ◽  
Postmenopausal Women ◽  
Maximal Exercise ◽  
Exercise Recovery ◽  
Active Recovery ◽  
Vigorous Exercise ◽  
Main Effect ◽  
Linear And Nonlinear

The authors compared the linear and nonlinear heart rate variability dynamics from rest through maximal exercise in postmenopausal women who trained at either moderate or high intensities. The outcome variables included the RR triangular index, TINN, SD1, SD2, SD1/SD2, DFA α1, DFA α2, and α1/α2. Maximal exercise reduced SD1, SD2, DFA α1, DFA α2, α1/α2, RRTri, and TINN in both groups and increased SD1/SD2 (p < .05). Two minutes of active recovery produced significant increases in SD1, SD2, DFA α1, and TINN, compared with exercise in both groups (p < .0001). There was also a significant main effect between groups for RRTri during exercise recovery, with the moderate group achieving higher levels (p < .04). The authors have shown that both moderate and vigorous exercise training can lead to a healthy response to maximal exercise and recovery, with the moderate group having a slightly improved recovery in the triangular index.

Metabolic adrenergic changes during submaximal exercise and in the recovery period in man

1979 ◽  
Vol 47 (4) ◽  
pp. 701-705 ◽  
Author(s):  
J. M. Pequignot ◽  
L. Peyrin ◽  
M. H. Mayet ◽  
R. Flandrois
Keyword(s):  
Recovery Period ◽  
Submaximal Exercise ◽  
Short Term ◽  
Lipid Mobilization ◽  
Healthy Men ◽  
Muscular Work ◽  
Urinary Levels ◽  
Postexercise Recovery ◽  
Vanilmandelic Acid

The urinary excretion of dihydroxyphenylalanine (DOPA), catecholamines (CA) [dopamine (DA), norepinephrine (NE), and epinephrine (e)], their 3-O-methylated derivatives [3-O-methyldopamine (3-MT), normetanephrine (NMN), and metanephrine (MN)], and their deaminated metabolites [dihydroxyphenylacetic acid (DOPAC) and vanilmandelic acid (VMA)] was studied in six healthy men, at rest during short-term (15 min) or exhaustive submaximal exercise, and in the 2-h postexercise recovery period. During short-term exercise only NE and VMA excretions increased, whereas in postexercise period only DA output was enhanced. Exhaustive muscular work induced a rise in NE and E excretion during the test, and an increase in DA, NE, and NMN urinary levels during postexercise recovery, while the output of deaminated metabolites was unaltered. It is concluded that both release and synthesis of CA are stimulated by submaximal exercise, which induces, in addition to NE, a specific release of DA. A possible role of NE in lipid mobilization during recovery from exhaustive muscular work is evoked. The origin and role of released DA are also discussed.

Role of Parasympathetic Activity in Heart Rate Recovery After Maximal Exercise in Cardiac Patients

2004 ◽  
Vol 36 (Supplement) ◽  
pp. S213-S214
Author(s):  
Linda R. Davrath ◽  
Itzik Pinhas ◽  
Amit Beck ◽  
Mickey Scheinowitz ◽  
Dan Elian ◽  
...  
Keyword(s):  
Heart Rate ◽  
Maximal Exercise ◽  
Heart Rate Recovery ◽  
Cardiac Patients ◽  
Parasympathetic Activity

Role of central respiratory muscle fatigue in endurance exercise in normal subjects

1994 ◽  
Vol 76 (1) ◽  
pp. 236-241 ◽  
Author(s):  
D. Marciniuk ◽  
D. McKim ◽  
R. Sanii ◽  
M. Younes
Keyword(s):  
Muscle Fatigue ◽  
Respiratory Muscle ◽  
Breathing Pattern ◽  
Normal Subjects ◽  
Submaximal Exercise ◽  
Respiratory Effort ◽  
Borg Scale ◽  
Respiratory Muscle Fatigue ◽  
Maximal Power Output

The role of central respiratory muscle fatigue in determining endurance time (ET) of steady-state ergometry, ventilation (VE), and breathing pattern during exhaustive submaximal exercise is not known. Six normal subjects exercised on a cycle ergometer to exhaustion at 72–82% of maximal power output on three occasions. During the second test, inspiratory muscle load was reduced (approximately 50% of baseline load) for all but the last 3 min of exercise. ET was determined, and VE, tidal volume (VT), respiratory rate (f), and sense of breathing effort (Borg scale) were assessed at different points during the assisted exercise and compared with the values obtained at the same time in identical tests without assist, carried out before and after the assisted test (different days). Borg scale rating was less and there was a nonsignificant trend for VT and VE to be higher and for f to be lower when the assist was in place than at the same time during the unassisted runs. In the last 3 min of exercise, when the respiratory load was comparable (assist removed) but ventilatory work history was different, there were no significant differences in sense of respiratory effort, VE, VT, or f between the experimental and control tests, and ET was also similar. We conclude that central respiratory muscle fatigue plays no role in determining ET, sense of respiratory effort, or breathing pattern in normal subjects during exhaustive submaximal exercise.

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