Effects of priming exercise on VO2 kinetics and O2 deficit at the onset of stepping and cycling

1989 ◽  
Vol 66 (5) ◽  
pp. 2023-2031 ◽  
Author(s):  
P. E. di Prampero ◽  
P. B. Mahler ◽  
D. Giezendanner ◽  
P. Cerretelli
Keyword(s):  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Double Exponential ◽  
Vo2 Kinetics ◽  
Male Subjects ◽  
O2 Deficit

Breath-by-breath O2 uptake (VO2) kinetics and increase of blood lactate concentration (delta Lab) were determined at the onset of square-wave stepping (S) or cycling (C) exercise on six male subjects during 1) transition from rest (R) to constant work load, 2) transition from lower to heavier work loads, wherein the baseline VO2 (VO2 s) was randomly chosen between 20 and 65% of the subjects' maximal O2 uptake (VO2 max), and 3) inverse transition from higher to lower work loads and/or to rest. VO2 differences between starting and arriving levels were 20–60% VO2 max. In C, the VO2 on-response became monotonically slower with increasing VO2 s, the half time (t1/2) increasing from approximately 22 s for VO2 s = R to approximately 63 s when VO2 s approximately equal to 50% VO2 max. In S, the fastest VO2 kinetics (t1/2 = 16 s) was attained from VO2 s = 15–30% VO2 max, the t1/2 being approximately 25 s when starting from R or from 50% VO2 max. The slower VO2 kinetics in C were associated with a much larger delta Lab. The VO2 kinetics in recovery were essentially the same in all cases and could be approximated by a double exponential with t1/2 of 21.3 +/- 6 and 93 +/- 45 s for the fast and slow components, respectively. It is concluded that the O2 deficit incurred is the sum of three terms: 1) O2 stores depletion, 2) O2 equivalent of early lactate production, and 3) O2 equivalent of phosphocreatine breakdown.(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.

Efficiency of anaerobic work

1978 ◽  
Vol 44 (4) ◽  
pp. 564-570 ◽  
Author(s):  
L. B. Gladden ◽  
H. G. Welch
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
O2 Uptake ◽  
Vo2 Max ◽  
External Work ◽  
Anaerobic Work ◽  
Steady Level ◽  
Submaximal Work ◽  
Aerobic And Anaerobic

This study was undertaken to compare the efficiency of aerobic and anaerobic work. Nine subjects worked at approximately 100% VO2 max for 2 min while inspiring gas mixtures with O2 fractions ranging from 0.13 to 0.21. Exercise O2 uptake, recovery O2 uptake, and blood lactate concentration were measured. Steady level O2 uptake was measured in normoxia at submaximal loads of about 30, 50, and 70% of VO2 max. Fast recovery O2 uptake did not change as PIO2 was varied. Exercise O2 uptake and blood lactate concentrations were linearly related to PIO2. The ratio of the slopes of these lines provided an empirical expression of the O2 equivalent of blood lactate. This ratio was constant, suggesting that it is not less efficient to use ATP synthesized anaerobically. Energy input from lactate was calculated using this factor. Efficiency decreased as power output increased even at the submaximal work rates. This may result from either 1) a decrease in muscle efficiency, 2) an increase in metabolism that is not directly related to the external work, or 3) some combination of 1 and 2.

Effect of exercise on epinephrine turnover in trained and untrained male subjects

1985 ◽  
Vol 59 (4) ◽  
pp. 1061-1067 ◽  
Author(s):  
M. Kjaer ◽  
N. J. Christensen ◽  
B. Sonne ◽  
E. A. Richter ◽  
H. Galbo
Keyword(s):  
Work Load ◽  
Hot Water ◽  
Plasma Epinephrine ◽  
Work Intensity ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Work Time ◽  
Arterial Blood ◽  
Male Subjects ◽  
Secretory Capacity

The kinetics underlying plasma epinephrine concentrations were studied. Six athletes (T) and six sedentary males (C) were given intravenous infusions of 3H-labeled epinephrine, after which arterial blood was drawn. They rested sitting and bicycled continuously to exhaustion (60 min at 125 W, 60 min at 160 W, 40 min at 200 W, and 240 W to the end). Work time was 154 +/- 13 (SE) (T) and 75 +/- 6 (C) min. At rest, epinephrine clearance was identical [28.4 +/- 1.3 (T) vs. 29.2 +/- 1.8 (C) ml . kg-1 . min-1], but plasma concentration [1.42 +/- 0.27 (T) vs. 0.71 +/- 0.16 (C) nmol . l-1] and, accordingly, secretion [2.9 +/- 0.7 vs. 1.5 +/- 0.4 nmol . min-1] were higher (P less than 0.05) in T than C subjects. Epinephrine clearance was closely related to relative work load, decreasing from 15% above the basal level at 30% of maximal O2 uptake (VO2 max) to 22% below at 76% of VO2 max. Epinephrine concentrations increased much more with work intensity than could be accounted for by changes in clearance and were, at exhaustion, higher (P less than 0.05) in T (7.2 +/- 1.6) than in C (2.5 +/- 0.7 nmol . l-1) subjects despite similar glucose, heart rate, and hematocrit values. At a given load, epinephrine clearance rapidly became constant, whereas concentration increased continuously. Forearm extraction of epinephrine invalidated use of blood from a cubital vein or a hand vein arterialized by hot water in turnover measurements. During exercise, changes in epinephrine concentrations reflect changes in secretion rather than in clearance. Training may increase adrenal medullary secretory capacity.

Oxygen debt in submaximal and supramaximal exercise in children at high and low altitude

1986 ◽  
Vol 60 (1) ◽  
pp. 209-215 ◽  
Author(s):  
N. Fellmann ◽  
M. Bedu ◽  
H. Spielvogel ◽  
G. Falgairette ◽  
E. Van Praagh ◽  
...  
Keyword(s):  
Lactate Concentration ◽  
Anaerobic Capacity ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
Maximal Heart Rate ◽  
O2 Uptake ◽  
Bicycle Exercise ◽  
Linear Relationships ◽  
Low Altitude ◽  
O2 Debt

The effect of high altitude (HA) on O2 debt and blood lactate concentration [( L]) was examined in 10- to 13-yr-old children who exhibited the same level of physical fitness. Fifty-one children acclimatized to HA (3,700 m) were compared with 40 children living at low altitude (LA, 330 m) during submaximal (20–95% maximal aerobic power, MAP), maximal and supramaximal (115% MAP) bicycle exercise. Results showed that 1) maximal O2 uptake (VO2max) and maximal heart rate were significantly (P less than 0.001) lower at HA than at LA by 15% and 11 beats X min-1, respectively; 2) for a given absolute work load, O2 debt was higher at HA than at LA, and the slopes of the linear relationships between O2 debt and O2 uptake were significantly higher at HA; 3) when related to percent of VO2max, O2 debts in HA and LA were similar; for 115% MAP maximal O2 debt and [L] were not significantly different (maximal O2 debt, 45.7 +/- 2.7 and 45.9 +/- 3.8 ml X kg-1; [L], 6.0 +/- 0.3 and 6.7 +/- 0.5 mM); and 4) linear relationships between maximal O2 debt and [L] were the same at HA and LA. This suggests that HA did not modify the anaerobic capacity in children.

scholarly journals Time required for the restoration of normal heavy exercise V̇o2 kinetics following prior heavy exercise

2006 ◽  
Vol 101 (5) ◽  
pp. 1320-1327 ◽  
Author(s):  
Mark Burnley ◽  
Jonathan H. Doust ◽  
Andrew M. Jones
Keyword(s):  
Blood Lactate ◽  
Priming Effect ◽  
Slow Component ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
V̇o2 Kinetics ◽  
Time Required ◽  
Male Subjects

Prior heavy exercise markedly alters the O2 uptake (V̇o2) response to subsequent heavy exercise. However, the time required for V̇o2 to return to its normal profile following prior heavy exercise is not known. Therefore, we examined the V̇o2 responses to repeated bouts of heavy exercise separated by five different recovery durations. On separate occasions, nine male subjects completed two 6-min bouts of heavy cycle exercise separated by 10, 20, 30, 45, or 60 min of passive recovery. The second-by-second V̇o2 responses were modeled using nonlinear regression. Prior heavy exercise had no effect on the primary V̇o2 time constant (from 25.9 ± 4.7 s to 23.9 ± 8.8 s after 10 min of recovery; P = 0.338), but it increased the primary V̇o2 amplitude (from 2.42 ± 0.39 to 2.53 ± 0.41 l/min after 10 min of recovery; P = 0.001) and reduced the V̇o2 slow component (from 0.44 ± 0.13 to 0.21 ± 0.12 l/min after 10 min of recovery; P < 0.001). The increased primary amplitude was also evident after 20–45 min, but not after 60 min, of recovery. The increase in the primary V̇o2 amplitude was accompanied by an increased baseline blood lactate concentration (to 5.1 ± 1.0 mM after 10 min of recovery; P < 0.001). Baseline blood lactate concentration was still elevated after 20–60 min of recovery. The priming effect of prior heavy exercise on the V̇o2 response persists for at least 45 min, although the mechanism underpinning the effect remains obscure.

Acute anemia increases lactate production and decreases clearance during exercise

1989 ◽  
Vol 67 (2) ◽  
pp. 756-764 ◽  
Author(s):  
S. G. Gregg ◽  
R. S. Mazzeo ◽  
T. F. Budinger ◽  
G. A. Brooks
Keyword(s):  
Blood Glucose ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Flow Distribution ◽  
Plasma Catecholamine ◽  
Metabolic Clearance ◽  
Sprague Dawley ◽  
Mean Values

We evaluated whether elevated blood lactate concentration during exercise in anemia is the result of elevated production or reduced clearance. Female Sprague-Dawley rats were made acutely anemic by exchange transfusion of plasma for whole blood. Hemoglobin and hematocrit were reduced 33%, to 8.6 +/- 0.4 mg/dl and 26.5 +/- 1.1%, respectively. Blood lactate kinetics were studied by primed continuous infusion of [U-14C]lactate. Blood flow distribution during rest and exercise was determined from injection of 153Gd- and 113Sn-labeled microspheres. Resting blood glucose (5.1 +/- 0.2 mM) and lactate (1.9 +/- 0.02 mM) concentrations were not different in anemic animals. However, during exercise blood glucose was lower in anemic animals (4.0 +/- 0.2 vs. 4.6 +/- 0.1 mM) and lactate was higher (6.1 +/- 0.4 vs. 2.3 +/- 0.5 mM). Blood lactate disposal rates (turnover measured with recyclable tracer, Ri) were not different at rest and averaged 136 +/- 5.8 mumol.kg-1.min-1. Ri was significantly elevated in both control (260.9 +/- 7.1 mumol.kg-1.min-1) and anemic animals (372.6 +/- 8.6) during exercise. Metabolic clearance rate (MCR = Ri/[lactate]) did not differ during rest (151 +/- 8.2 ml.kg-1.min-1); MCR was reduced more by exercise in anemic animals (64.3 +/- 3.8) than in controls (129.2 +/- 4.1). Plasma catecholamine levels were not different in resting rats, with pooled mean values of 0.45 +/- 0.1 and 0.48 +/- 0.1 ng/ml for epinephrine (E) and norepinephrine (NE), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Sporting myths: the REAL role of lactate during exercise

2016 ◽  
Vol 19 (5) ◽  
Author(s):  
T Mann
Keyword(s):  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Endurance Performance ◽  
Post Exercise ◽  
Early Exercise ◽  
Important Intermediate ◽  
Lactate Formation ◽  
Exercise Muscle

Background. Lactate or, as it was customarily known, ‘lactic acid’ was one of the first molecules to attract the attention of early exercise scientists, mainly because blood lactate concentration could be measured and was shown to increase with increasing exercise intensity. This connection resulted in lactate being associated with numerous other events associated with high-intensity exercise including muscle cramps, fatigue, acidosis and post-exercise muscle soreness. Nobel prize-winning research by AV Hill and Otto Meyerhof provided a rational explanation linking lactate to anaerobiosis and acidosis, which resulted in this relationship being widely accepted as fact. It was only following isotopic tracer studies of George Brooks and others that the true role of lactate during rest and exercise was revealed. Conclusions. Lactate is now acknowledged as an important intermediate of carbohydrate metabolism, taken up from the blood by tissues such as skeletal and cardiac muscle as a substrate for oxidation. Furthermore, lactate formation consumes a proton, thereby buffering against muscle acidosis. For this reason, lactate production forms an essential aid to endurance performance rather than a hindrance.

Exercise in Merino sheep dash the relationships between work intensity, endurance, anaerobic threshold and glucose metabolism

1991 ◽  
Vol 42 (4) ◽  
pp. 599 ◽  
Author(s):  
DW Pethick ◽  
CB Miller ◽  
NG Harman
Keyword(s):  
Glucose Metabolism ◽  
Anaerobic Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
Respiratory Alkalosis ◽  
Work Rate ◽  
Glycerol Concentration ◽  
Work Intensity ◽  
Intensity Of Exercise

The effect of exercise intensity on (i) the ability of sheep to sustain exercise and (ii) glucose metabolism was investigated in fed non-pregnant adult Merino ewes. Five animals were prepared with cannulae to study the splanchnic tissues using the arteriovenous difference technique either at rest or during 8 levels of exercise: 3, 5, 7 and 9 km h-1 at either 0� or 9� incline. The anaerobic threshold, determined by elevation of blood lactate concentration or lactate/pyruvate ratio, occurred at a work rate of about 6-10 watts/kg body wt (7 km h-1 on 0� incline, 3 km h-1 on 9� incline). Only exercise well in excess of the anaerobic threshold resulted in ewes showing fatigue. Fatigue was not associated with carbohydrate depletion or lacticacidosis. Changes in the partial pressure of CO2 and the pH of blood indicated a marked respiratory alkalosis that was related to the severity of exercise, suggesting that thermoregulation may have been an important component of fatigue. Splanchnic blood flow declined when the intensity of exercise exceeded the anaerobic threshold; however, this did not compromise splanchnic function as assessed by oxygen and metabolite uptake. During exercise below the anaerobic threshold euglycemia was maintained while a pronounced hyperglycemia, that became more severe as the work rate increased, was found for exercise above the anaerobic threshold. The release of glucose by the liver increased significantly at all work rates and markedly so after the anaerobic threshold, such that the resultant hyperglycemia was consistent with an exaggerated hepatic glucose release due to 'feed forward' control. The contribution of lactate and glycerol to gluconeogenesis, assuming complete conversion, remained constant at 18-25% except at the highest work load where the contribution significantly declined to 9%. The decline was due to (i) saturation of hepatic lactate uptake and (ii) a failure for glycerol concentration and so uptake to increase beyond a work rate of 22 W kg-1. The requirement for gluconeogenic end products of digestion for animals grazed under extensive conditions would be 9-30% greater than for animals not exercising, depending upon the speed and inclination of exercise.

Metabolic recovery from exhaustive activity by a large lizard

1980 ◽  
Vol 48 (4) ◽  
pp. 689-694 ◽  
Author(s):  
T. T. Gleeson
Keyword(s):  
Temperature Dependence ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Excess Oxygen ◽  
Temporal Separation ◽  
Metabolic Recovery ◽  
Strenuous Activity ◽  
Lactate Removal

Gas exchange (VO2 and VCO2) and blood lactate concentration were measured in the lizard Amblyrhynchus cristatus at 25 and 35 degrees C during resting, running, and recovery after exhaustion (less than or equal to 180 min) to analyze the temperature dependency of metabolic recovery in this lizard. Amblyrhynchus exhausted twice as fast (4.2 vs. 8.8 min) at 25 degrees C than when running at the same speed at 35 degrees C. At both temperatures, VO2 and VCO2 increased rapidly during activity and declined toward resting levels during recovery in a manner similar to other vertebrates. Respiratory quotients (R, where R = VCO2/VO2) exceeded 2.0 after exhaustion at both temperatures. Extensive lactate production occurred during activity; blood lactate concentrations ranged from 1.0 to 1.7 mg lactate/ml blood after activity. Net lactate removal exhibited a temperature dependence. Blood lactate concentrations remained elevated hours after VO2 returned to normal. Endurance was reduced in lizards that had recovered aerobically but still possessed high lactate concentrations. The temporal separation of the excess oxygen consumption and lactate removal suggests that the concept of the lactacid oxygen debt is not applicable to this animal. The temperature dependence of total metabolic recovery suggests a benefit for Amblyrhynchus that select warm basking temperatures following strenuous activity.

scholarly journals Determination of Anaerobic Capacity - Reliability and Validity of Sprint Running Tests

2020 ◽  
Vol 29 (2) ◽  
pp. 129-137
Author(s):  
Corinna Wawer ◽  
Oliver Heine ◽  
Hans-Georg Predel ◽  
Da-Sol Park ◽  
Woo-Hwi Yang
Keyword(s):  
Lactate Concentration ◽  
Anaerobic Capacity ◽  
Lactate Production ◽  
Reliability And Validity ◽  
Sprint Running ◽  
Incremental Step ◽  
Male Subjects ◽  
Performance Diagnostics ◽  
Maximum Lactate

PURPOSE: A number of physiological diagnostics were developed. However, the timeline-related diagnostics of maximal anaerobic glycolytic capacity remain unclear. The objective of this study was to evaluate the reliability and validity of a sprint running test to assess the anaerobic capacity.METHODS: The study was divided into three parts. Sixty-one male (24±4 years, 181.0±4.3 cm; 78.5±5.9 kg) and twelve female (25±3 years, 167.0±0.6 cm, 60.4±5.7 kg) sports students participated in this study. Twenty-five subjects (13 males, 24±2 years, 181.0±0.5 cm, 78.5±5.9 kg; 12 females, 25±3 years, 167.0±0.6 cm, 60.4±5.7 kg) performed incremental step tests at running track and several linear sprints on a running track (LSRT) with different time durations (8, 10, 12, and 14 seconds)(part I) on different days. Twenty-five male subjects (24±3 years, 180.7±6.7 cm, 84.6±8.8 kg) conducted a 10 or 12 second sprint running on a non-motorized treadmill (NMT)(part II). In part III, twenty-three male subjects (24±2 years, 181.4±5.8 cm, 74.5±7.4 kg) ran a 10 second LSRT and NMT on consecutive days. Capillary blood samplings were taken before (Lac<sub>r</sub>) and after the sprint running for ten minutes at one minute intervals to find out maximal lactate concentration after exercise and to calculate the maximum lactate production rate (LPR<sub>max</sub>).RESULTS: For all parts reliability for LPR<sub>max</sub> was proven (Part I: 8 seconds: ICC: <i>r</i>=.89; 10 seconds: ICC: <i>r</i>=.82; 12 seconds: ICC: <i>r</i>=.92; 14 seconds: <i>r</i>=.84, respectively; Part II: 10 seconds: ICC: <i>r</i>=.76; 12 seconds: ICC: <i>r</i>=.79). To analyze validity for LPR<sub>max</sub>, Part III was conducted and proven valid (ICC: <i>r</i>=.96, p=.074).CONCLUSIONS: We demonstrate that LSRT and NMT reliably determine anaerobic capacity and can be used as a valid tool for physiological performance diagnostics.

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