Rate Of Lactate Removal Research Articles

Inspiratory Muscle Training Improves Maximal Inspiratory Pressure Without Increasing Performance in Elite Swimmers

To analyze the effect of inspiratory muscle training (IMT) on the maximal inspiratory mouth pressure (MIP) and performance of elite swimmers. Eight participants performed a 3000-m swimming test (T-3000), followed by blood lactate measurements at 1 and 5minutes postexercise.. The testing protocol was carried out before and after 6weeks of IMT, in which a high-volume IMT group (HV-IMT) (n = 4) performed IMT twice a day-in the morning in a seated position and in the afternoon in a concurrent session of IMT and core muscle training. Also, a low-volume IMT group (LV-IMT) (n = 4) performed IMT in the morning session only. After the intervention, both groups improved their MIP, HV-IMT (132.75 [27.42] to 156.75 [21.88] cmH2O; P = .010; d = 0.967) and LV-IMT (149.25 [22.82] to 171.50 [23.74] cmH2O; P = .013; d = 0.955), without a significant difference between groups (P = .855). Regarding swimming performance, there were no changes between groups in the T-3000 (P = .472) or lactate removal rate (P = .104). IMT increased inspiratory muscle strength in elite swimmers, but there was no association or meaningful impact on swimming performance.

Effects of sodium bicarbonate ingestion on prolonged running performance and recovery in trained runners

Background: While the effects of sodium bicarbonate on buffering capacity have been repeatedly examined on short-term and high-intensity exercise performance, studies on prolonged endurance performances such as running are scarce. Thus, the purpose of this study was to investigate the effect of NaHCO? (0.3 g/kgBW) ingestion 60-minutes prior to the prolonged running testing and recovery in trained runners.Methods: A total of 10 trained male runners (age: 20.70±1.10 years; weight: 61.30±6.20 kg; height: 166.10±3.70 cm; VO2max 58.43±5.62 mL/kg/min) were recruited in this study. Subjects undertook 1 preliminary testing and 2 experimental trials: Sodium Bicarbonate (SB) and Placebo (PLA) trials, which consisted of: (i) a 60-minutes Prolonged Exercise Testing (PET) (30-minutes of constant speed run at 65 % of VO2max followed by a self-selected speed of 30-minutes maximum distance run) and (ii) 30-minutes of the recovery period in randomized order. Data were analyzed using SPSS version 23 for Windows.Results: Subjects ran further during the SB trial than the PLA trial (5,233.60±524.70 m vs. 5,021.40±440.10 m; p=0.012) associated with a greater blood lactate level (5.66±1.09 mmol/L vs. 3.68±0.71 mmol/L). Ingestion of SB drinks significantly increased urine pH during PET and recovery period (p<0.01). During post-recovery, a greater decrease in blood lactate level was found in the SB trial (2.53±0.91 mmol/L; 55%) as compared to the PLA trial (2.17±0.50 mmol/L; 41%) (p<0.01).Conclusion: The ingestion of NaHCO?(0.30 g/kgBW) 60-minutes prior to the PET improved prolonged running performance associated with a faster lactate removal rate during the 30-minutes recovery period.

Does the type of foam roller influence the recovery rate, thermal response and DOMS prevention?

Supporting post-exercise recovery requires choosing not only the right treatment but also the equipment, in which the impact is not always clear. The study aimed to determine the effect of foam rolling on the rate of lactate removal and DOMS prevention and whether the type of foam roller is effective in the context of post-exercise recovery. This randomized trial enrolled 33 active healthy males divided into three groups of eleven individuals: foam rolling with a smooth (STH) or grid roller (GRID) or passive recovery (PAS). All the participants performed full squat jumps for one minute. Examination took place at rest (thermal imaging of skin temperature-[Tsk] and blood lactate-[LA]), immediately following exercise (Tsk & LA), immediately after recovery treatment (Tsk) and after 30 minutes of rest (Tsk & LA). Their pain levels were assessed using the Visual Analog Scale (VAS) 24, 48, 72, and 96 hours after exercise. The magnitude of lactate decrease depended on the type of recovery used. In the PAS group, the decrease in lactate concentration by 2.65 mmol/L following a half-hour rest was significantly lower than that in the other groups (STH vs. PAS p = 0.042 / GRID vs. PAS p = 0.025). For thermal responses, significant differences between both experimental groups were noted only 30 minutes after exercise. A significant decrease in pain in the STH group occurred between 48 and 96 hours, while the GRID group showed a systematic significant decrease in VAS values in subsequent measurements. Changes in VAS values in subsequent measurements in the PAS group were not statistically significant (p>0.05). Foam rolling seems to be effective for enhancing lactate clearance and counteracting DOMS, but the type of foam roller does not seem to influence the recovery rate.

Occlusion Training During Specific Futsal Training Improves Aspects of Physiological and Physical Performance.

This study aimed to examine the effects of lower limb blood flow restriction (BFR) performed during 3-a-side futsal game training on aerobic and anaerobic performance of futsal players. Twelve male futsal players were randomized into two groups (n = 6); both groups performed ten sessions of the 3-a-side game every other day in half of a futsal court; but one group trained under BFR conditions. Pneumatic cuffs used for the BFR group were inflated to 110% leg systolic blood pressure and increased by 10% after each two completed sessions. Before and after the training sessions subjects completed a series of tests to assess aerobic and anaerobic performances along with changes in blood lactate and anabolic and catabolic hormones. All aerobic and anaerobic performance variables improved in both group after training, however improvements in mean power (12.2%, p = 0.03), run time to fatigue (TTF), (7.1%, p = 0.02) and running economy (RE), (-22.7%, p = 0.01) were significantly greater in the BFR group. There were also significant increases in growth hormone (p = 0.01), testosterone to cortisol ratio at first session (p = 0.01) and rate of lactate removal (p = 0.01) at last session in the BFR group compared to the non-BFR group. Small-sided game (SSG) training with the addition of BFR because of accumulated metabolites and hormonal changed leads to substantially greater increases in performance than SSGs training alone.

Comparison of Efficacy of Static Stretching and Sports Massage on the Removal Rate of Blood Lactate Level after Static Cycling in Female Individuals

Background: The Muscle soreness is a result of lactate accumulation after sub maximal exercise done by the athlete. It is necessary to clear the lactate for optimum performance. Purpose: Hence the current study has been done to see the effect of static stretching and sports massage on removal rate of Blood lactate. Methodology: The study was conducted on 60 female college students who fall into selection criteria. The subjects were randomly divided into two groups; Static Stretching was given to group A and Sports massage was given to group B to check the clearance rate of blood lactate after 20 minutes of static cycling. 3 readings of blood lactate level were taken i.e. first reading before the static cycling, second reading after the static cycling and the third after the interventions. The measurements were analyzed to check the efficacy of static cycling and sports massage on blood lactate removal rate. Results: The results of the study showed both the techniques are effective with p value of 0.0001 to remove blood lactate where the static stretching improves the clearance with mean value of 1.0906 and sports massage improves with mean value of 0.0357. Conclusion: It is concluded from the study that the static stretching and sports massage both the techniques are effective in improving blood lactate clearance rate but static stretching is more effective than sports massage.

ARTERIAL LACTATE LEVELS CAN PREDICT MORTALITY IN SEPSIS

SESSION TITLE: Wednesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM PURPOSE: Sepsis and septic shock may prove fatal hence more than two thirds of septic patients are admitted to the intensive care unit (ICU). Only a few laboratory tests for the markers of sepsis, are currently available. The recent Sepsis-3 guidelines defines sepsis as a dysregulated immune response to infection, and septic shock as persistent hypotension requiring vasopressors with a serum lactate of >2mmol/L despite adequate volume resuscitation. Hence lactate is an important biomarker. This study was aimed to compare the initial lactate level, lactate level after 6 hours of resuscitation and the combined results of both lactate levels of septic patients to predict mortality in critical care settings METHODS: 100 patients with the diagnosis of sepsis or septic shock admitted to ICU were enrolled in this cross-sectional study. One sample of arterial lactate was drawn on presentation. Another sample was drawn after six hours of resuscitation as per ICU protocol that included fluid challenge, vasopressors to keep a MAP > 65mmhg, hydrocortisone, glycemic control and nutrition. Demographic characteristics, acute physiologic assessment and chronic health evaluation (APACHE-II) scores, the sequential organ failure assessment (SOFA) scores, central venous saturations of oxygen (SCVO2), MAP, and lactate clearance levels were noted for all patients. Chi-square analysis was used for evaluation of correlation between mortality and lactate clearance. Quantitative variables were analyzed with independent sample t-tests where the numerical variables had a normal distribution. ANCOVA testing was used for comparison of arterial lactate level between survivors and non-survivors RESULTS: Patients were dividing into 3 groups. Group-1 if their admission concentrations of the arterial lactate were < 3.2mmol/l and had an arterial lactate removal rate of ≥20%; Group-2 if only one of the two criteria were met or Group-3 if they had an admission lactate levels ≥ 3.2mmol with less than 20% lactate removal rate. The sensitivity and specificity of this model for mortality prediction was 88% and 95% respectively with a predictive value of 91% based on ROC curve analysis. CONCLUSIONS: From the 17 patients in Group 2, 10 (59%) died, while from 63 patients in Group 1, only 5 patients (8%) died. 100% of Group 3 patients died. CLINICAL IMPLICATIONS: The study indicates that the combination of arterial lactate level and the rate of lactate removal can be used as useful predictor of mortality in critically sick septic patients DISCLOSURES: no disclosure on file for Ata Mahmoodpoor; no disclosure on file for Nader Nader; No relevant relationships by Rukma Parthvi, source=Web Response no disclosure on file for Sarvin Sanaie

Continuous biological removal of selenate in the presence of cadmium and zinc in UASB reactors at psychrophilic and mesophilic conditions

This study investigated the continuous biological removal of selenate [Se(VI)] in the presence of cadmium [Cd(II)] and zinc [Zn(II)] by anaerobic granular sludge in two upflow anaerobic sludge blanket (UASB) reactors operating under psychrophilic (17.5 ± 0.4 ℃) and mesophilic (30 ± 0.5 ℃) conditions for 42 and 74 days, respectively. Se(VI) and total selenium (Se) removal efficiencies reached, respectively, 99.6% and 95.0% in the UASB reactor operating at psychrophilic conditions. Cd(II) and Zn(II) removal efficiencies by the mesophilic UASB reactor reached, respectively, 99.2% and 96.2%. In the presence of Cd and/or Zn in the influent, both Se(VI) and total Se had a higher removal efficiency than when solely feeding Se(VI), both at 17.5 ℃ and 30 ℃. The lactate removal rates of the UASB reactors amounted to 1.0–1.2 mM/h. The mass balance showed 64.8%–79.5% of the supplied Se was entrapped in the biomass at the end of the experiment. The polysaccharides and protein concentrations of the extracellular polymeric substances (EPS) increased ∼3 to 5 times upon heavy metal exposure. A dramatic change in the microbial community occurred in the UASB reactors during long term operation. This study showed that UASB reactors have desirable Se(VI), Cd(II) and Zn(II) removal efficiencies both at 17.5 and 30 ℃.

The Comparisons of Blood Lactate Concentration and Removal Rate after Aerobic and Anaerobic Maximal Exercise

PURPOSE This study examined blood lactate concentration and removal rate after aerobic and anaerobic maximal exercise test in sedentary middle-age women. METHODS Ten sedentary middle-age women (aged 52.7±3.3 years) were performed after aerobic (Aero group) and anaerobic maximal exercise (Anaero group) test, VO2max test and Wingate test, by cross-over repeated design with biweekly. The blood was collected from cardinal veins at before and immediately after test for measurement of lactate and lactate dehydrogenase (LDH). And it was also collected from fingertip at before, immediately after and then recovery 5, 10, 15, 30 minutes after each maximal test. Lactate removal rate (%) were calculated by bellow formulas: ={1-[(Lactate at 30 minutes. after test-Resting lactate)/Increased lactate]}×100. RESULTS The blood lactate concentration from fingertip after both maximal test significantly increased immediately after test (p<.001 respectively), and maintained until recovery of 30 minutes. after test (p<.01, p<.001 respectively) in spite of there were no significant differences between both Aero and Anaero group. There were also no significant differences between both test groups in blood maximum lactate (p=.090) and increased lactate concentration (p=.058). No significant differences were also observed between the two groups in lactate removal rate (p>.05). There are positive correlationship among muscle mass and blood maximum lactate and increased lactate concentration (p<.01). CONCLUSIONS These results indicate that exercise was performed by anaerobic at end of test in VO2max test. Also suggested that the greater muscle mass may induce the more lactate accumulation, thereby increasing lactate tolerance. 색인어: ìœ ì‚°ì†Œ, 무산소, 최대운동, 혈중 ì –ì‚°, LDH Keywords: Aerobic, Anaerobic, Maximal exercise, Blood lactate, LDH

Muscle MCT4 Content Is Correlated with the Lactate Removal Ability during Recovery Following All-Out Supramaximal Exercise in Highly-Trained Rowers.

The purpose of this study was to test if the lactate exchange (γ1) and removal (γ2) abilities during recovery following short all-out supramaximal exercise correlate with the muscle content of MCT1 and MCT4, the two isoforms of the monocarboxylate transporters family involved in lactate and H+ co-transport in skeletal muscle. Eighteen lightweight rowers completed a 3-min all-out exercise on rowing ergometer. Blood lactate samples were collected during the subsequent passive recovery to assess an individual blood lactate curve (IBLC). IBLC were fitted to the bi-exponential time function: La(t) = [La](0) + A1(1 − ) + A2(1 − ) where [La](0) is the blood lactate concentration at exercise completion and the velocity constants γ1 and γ2 denote the lactate exchange and removal abilities, respectively. An application of the bi-compartmental model of lactate distribution space allowed estimation of the lactate removal rate at exercise completion [LRR(0)]. Biopsy of the right vastus lateralis was taken at rest to measure muscle MCT1 and MCT4 content. Fiber type distribution, activity of key enzymes and capillary density (CD) were also assessed. γ1 was correlated with [La](0) (r = −0.54, P < 0.05) but not with MCT1, MCT4 or CD. γ2 and LRR(0) were correlated with MCT4 (r = 0.63, P < 0.01 and r = 0.73, P < 0.001, respectively) but not with MCT1 or cytochrome c oxidase activity. These findings suggest that the lactate exchange ability is highly dependent on the milieu so that the importance of the muscle MCT1 and MCT4 content in γ1 was hidden in the present study. Our results also suggest that during recovery following all-out supramaximal exercise in well-trained rowers, MCT4 might play a significant role in the distribution and delivery of lactate for its subsequent removal.

Physical testing prior to returning to normal sports activity for elite athletes following ACL injury

Anterior cruciate ligament (ACL) injury is among the most frequent sports-related injuries especially in contact sports such as football, basketball, soccer and skiing. In professional sports, ACL injury has a...

Effect of Altitude on Lactate Removal Rates following High-Intensity Exercise

Effect of Altitude on Lactate Removal Rates following High-Intensity Exercise

Effect of Altitude on Lactate Removal Rates following High-Intensity Exercise

0766 PURPOSE: To determine the effect of moderate altitude exposure on the washout of blood lactate following high-intensity exercise. METHODS: Six healthy, active subjects (mean age = 20.1 +/− 3.4 yrs) were asked to complete a graded-exercise test to exhaustion on a cycle ergometer at sea level (SL1), upon acute exposure to 3400 m (ALT1), two weeks following acclimatization at 3400 m (ALT2), and upon return to sea level (SL2). Workloads were increased every two minutes following a two minute warmup. Venous blood lactate measurements were taken via an indwelling catheter without stasis every two minutes during and every two minutes after the exercise was completed until lactate levels were decreased to half of their maximum values (T 1/2). RESULTS: T1/2 significantly increased during ALT1 (18.2 ± 6.0 min) relative to SL1 (9.0 ± 2.2 min). T1/2 decreased during ALT2 (12.4 ± 6.1 min) and SL2 (13.6 ± 3.84 min) but did not return to SL1 levels. CONCLUSIONS: These data suggest that altitude exposure has a direct effect on lactate washout following high-intensity exercise. The observed increase in lactate removal times upon acute exposure to altitude might be due to the hypoxic vasoconstriction that occurs at altitude.

Rate of decline in blood lactate during passive recovery: effects of the kind of exercise and aerobic capacity

O objetivo deste estudo foi verificar os efeitos, durante a recuperação passiva (RP), do tipo de exercício realizado previamente (corrida ou natação) e da capacidade aeróbia, determinada através do limiar anaeróbio (LAn), sobre a taxa de remoção do lactato sangüíneo (RLS), após um exercício de alta intensidade. Participaram do estudo nove indivíduos ativos do sexo masculino (20,66 + 3,24 anos; 1,76 + 0,04 m e; 71,22 + 4,26 kg). O LAn foi determinado medindo-se a concentração de lactato (YSL 2300 STAT) após cada tiro nos testes de corrida (3 x 1200 m progressivos) e de natação (3 x 200 m progressivos). A velocidade de cada exercício correspondente a 4 mM (LAn) foi calculada por interpolação linear. A seguir, os indivíduos realizaram em dias diferentes, duas sessões experimentais: corrida - 2 x 200 m na máxima velocidade, com 2 min de intervalo entre as tentativas; natação - 2 x 50 m na máxima velocidade, com 2 min de intervalo entre as tentativas. Cada procedimento deste foi seguido por 30 min de RP Após um, sete, 12, 17 e 30 min do término do exercício de alta intensidade, foram coletados 25 pl de sangue para a medição do lactato. Utilizando-se a regressão linear entre o logaritmo da concentração de lactato e o tempo da recuperação, foi calculado o meio tempo (t 1/2) da RLS. A RP após a corrida (CP = 25,5 min), apresentou um t 1/2 significantemente maior do que a RP após a natação (NP = 18,6 min). O t 1/2 das seqüências CP e NP, não correlacionaram-se com a velocidade correspondente ao LAn, obtida respectivamente na corrida (r = -0,18) e na natação (r = -0,57). Houve correlação significante entre os t 1/2 das seqüências CP e NP (r = 0,77). Com base nestes resultados, pode-se concluir que a capacidade aeróbia, determinada através do LAn, parece não influenciar a velocidade de RLS durante a RP. Durante a RP, a velocidade de remoção do lactato sangüíneo é menor após o exercício de corrida do que de natação

The contribution of glucose cycling to the maintenance of steady-state levels of lactate by hepatocytes during glycolysis and gluconeogenesis.

When hepatocytes from fasted rats were incubated with 10 mM glucose, there was a linear accumulation of lactate and pyruvate for about 80 min after which steady-state concentrations of these metabolites became established. The rate of glycolysis, determined with [6-3H]glucose, was constant over the entire incubation period and was 50% greater than that calculated from carbon balance studies. This suggests that one-third of the glycolytic products formed were recycled to glucose. To enable study of the factors associated with the generation and maintenance of the lactate steady state and to measure accurately the carbon balance, incubations were performed using supraphysiological concentrations of glucose (20-80 mM). Under these conditions the initial rate of lactate accumulation and its concentration at steady state were shown to be dependent on the concentration of extracellular glucose. Rates of glycolysis were also measured using 40 mM [6-3H]glucose and [U-14C]glucose added alone, or in combination with a steady-state lactate concentration (3 mM). There was no effect on the rate of glycolysis determine with [6-3H]glucose, even when lactate was present in the medium. The difference in rates between measurements with the two isotopes reflect the apparent degree of glucose recycling which in the absence and presence of added lactate increased from 0.26 to 0.54 mumol C3 equivalents min-1.g-1 respectively. Identical studies employing [U-14C]lactate showed that glucose and CO2 were the major products of lactate metabolism under steady-state conditions and that the formation of lactate from [U-14C]glucose exactly balanced the rate of lactate removal as a result of oxidation and gluconeogenesis. These studies provide evidence for the concomitant operation of glycolysis and gluconeogenesis, even in the presence of high glucose concentrations. They also demonstrate that lactate steady states are achieved not by the cessation of glycolysis but rather by the removal of lactate and pyruvate at a rate equal to that of their production.

Lactic acid recovery profiles following exhaustive arm exercise on a canoeing ergometer.

In this study lactate removal rates were monitored in ten subjects during a 30-min recovery period following exhaustive arm exercise. Each subject experienced three recovery regimens on different occasions in random order. One recovery period consisted of supine rest while the other two were active, one incorporating low intensity arm exercise and the other consisting of low intensity leg exercise. Lactate clearance rates showed a significant difference between the recovery regimens, and a posteriori test indicated a significant difference between leg exercise and arm exercise in the recovery period and also between leg exercise and rest. There was no significant difference in lactate clearance between arm exercise and rest in the recovery period.

Thyroid hormones and muscle metabolism in dogs.

Muscle contents of ATP, ADP, AMP, creatine phosphate and creatine as well as glycogen, some glycolytic intermediates, pyruvate and lactate were compared in the intact, thyroidectomized and triiodothyronine (T3) treated dogs under resting conditions. After thyroidectomy muscle glycogen, glucose 1-phosphate and glucose 6-phosphate contents were significantly elevated while in T3-treated animals these variables were decreased in comparison with control dogs. Muscle free glucose was not altered by thyroidectomy but T3 treatment significantly increased its content. Muscle lactate content was elevated both in hypo- and hyperthyroid animals. Muscle ATP and total adenine nucleotide contents were significantly increased in hyperthyroid dogs while no differences were found between the three groups in the muscle creatine phosphate content. It is assumed that in T3-treated animals carbohydrate catabolism is enhanced in the resting skeletal muscle in spite of high tissue ATP content. Muscle metabolite alterations in hypothyroid dogs seem to reflect the hypometabolism accompanied by a diminished rate of glycogenolysis with inhibited rate of pyruvate oxidation or decreased rate of lactate removal from the cells.

Lactic acid removal and heart rate frequencies during recovery after strenuous rowing exercise.

Three tests were conducted to assess the effectiveness of three different intensities of exercise both in reducing blood lactic acid (LA) levels and in influencing subjects' heart rate (HR), following a 2000 m race in a rowing boat. In the first and second tests these variables were investigated during a 13 min recovery exercise at 60% and 40% of the preceding maximum rowing speed respectively. In the third test the subjects had a resting recovery. The results include a significant increase (P less than 0.001) in the rate of lactate removal following the 40% recovery compared with the 60% and resting recoveries. The HRs were significantly lower during the last minute of resting recovery compared with 40% and 60% recoveries (P less than 0.001). The same was true when 40% recovery was compared with 60% recovery (P less than 0.001). The present data suggest firstly that 40% of the maximum rowing speed is an appropriate pace for effective LA removal and secondly that, at least for trained rowers, 86% of their maximum HR can be taken as an indication of work of an intensity at or above anaerobic threshold.

Evidence for a lactate transporter in the plasma membrane of the rat hepatocyte.

1. The rate of uptake in 15 s of L- and D-lactate was studied in isolated hepatocyte preparations from starved rats. 2. Observations were also made of the effect of different concentrations of unlabelled L- and D-lactate on L-[14C]- and D-[14C]-lactate uptake. 3. Lactate uptake into hepatocytes appears to occur by two processes, one saturable and at least partially stereospecific, the other non-saturable, at least up to 28 mmol/l, and probably representing simple non-carrier assisted diffusion. 4. The 15 s uptake of lactate is inhibited by alpha-cyano-3-hydroxycinnamate and by rho-chloromercuriphenylsulphonate but not by the general anion transporter inhibitor 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid, ouabain or the structural analogue DL-rho-hydroxyphenyl-lactate. 5. Transporter-mediated lactate entry into liver cells is enhanced by lowered extracellular pH. 6. It is suggested that the contribution of the diffusion component of lactate entry into the cell may be exaggerated by the artifactual nature of the isolated hepatocyte preparation, and that under some circumstances in vivo, lactate transport into hepatocytes could determine the rate of lactate removal from blood.

Blood lactate concentration following maximum exercise in trained subjects.

The time when blood lactate reaches peak concentration following maximum exercise is unclear. The post exercise venous blood lactate concentration was determined serially for 30 minutes in 13 trained men following maximum exercise on a motor driven treadmill. Lactates were determined enzymatically in duplicate. The VO2 max and percent body fat was 65.1 +/- 4.8 ml.kg-1.min-1 and 11.4 +/- 1.4, respectively. The venous lactate reached a peak concentration at the 6th minute (14.2 mmol.L-1) of an inactive recovery, and declined linearly thereafter to reach a concentration of 7.43 +/- 0.60 mmol.L-1 at the 30th minute. The net rate of lactate removal was .30 mmol.L-1.min-1. Statistical analysis found no significant difference in lactate concentration during the 4th, 5th and 6th minute post exercise, indicating that these post exercise times may be appropriate to sample venous blood for peak lactate concentration.

Blood pyruvate recovery curves after short heavy submaximal exercise in man.

Arterial pyruvate and lactate concentrations were measured after short heavy submaximal exercise on a bicycle ergometer, at 10 or 30 s time intervals, on six male subjects. During most of the first 2 min of recovery pyruvate concentration decreased. Thereafter, it increased and reached its maximum within the 5th to 9th min of recovery. Finally, it decreased gradually as a function of time. Recovery curves could be accurately described after a short delay time following the end of the exercise, by a sum of three exponential terms according to the equation: (Formula: see text), where the time origin (to) is fixed at about 1-1.5 min(delay time) after the end of exercise, t is the time after to, Y(O) and Y(t) are the concentrations of pyruvate respectively at times zero and T, and Ai and zi are constants. The velocity constant of the final arterial blood pyruvate decrease was similar to that of the simultaneously measured lactate, indicating that the rate of lactate removal is closely related to that of pyruvate. This is consistent with the fact that pyruvate is a necessary intermediate in the lactate metabolism.