Lactate Curve Research Articles

The use of hyperoxia to accelerate recovery the organism after the floor exercises routines in artistic gymnastics

The research deals with the use of inhalation of concentrated oxygen in the regeneration interval after anaerobic load in Artistic Gymnastics. The aim of research ́s realization was to diagnose the impact of inhalation of concentrated oxygen (hyperoxia) on the recovery ́s duration on reaction of heart rate and the level of the lactate in capillary blood after the floor exercises. The experiment was implemented on three members of nation team of Slovakia in artistic gymnastics. During the experiment ́s realization, the heart rate of gymnasts was continuously monitored. One minute after each specific load and after 3-, 7- and 15-minute recovery, we applied measurements of the lactate levels in capillary blood. The experimental factor was anonymous inhalation of concentrated oxygen respectively air (in form of placebo) during the rest. Gymnasts regenerated after each specific load by the form of inhalation of concentrated oxygen or placebo. Diagnostics ́ results after floor exercises of all professional gymnasts suggest on decrease of anaerobic cover after oxygen´s inhalation and faster lactate ́s remetabolisation when comparing with placebo ́s inhalation. The lactate curve tended downward from the 1st minute in recovery with inhalation of concentrated oxygen. On the contrary inhaling placebo made lactate curve rise till 3rd minute, resp. till 7th minute and then tended downwards. It was also exhibited the decrease of heart rate the average 10 beats per minute less with oxygen ́s inhalation when compared with placebo ́s inhalation in 1st, 2nd and 3rd minute after floor exercises routines. According to this information we can consider that the inhalation of hyperoxic mixture was a method to accelerate the recovery after specific load of elite gymnasts.

Normalized lactate load as an independent prognostic indicator in patients with cardiogenic shock

BackgroundEarly prognosis evaluation is crucial for decision-making in cardiogenic shock (CS) patients. Dynamic lactate assessment, for example, normalized lactate load, has been a better prognosis predictor than single lactate value in septic shock. Our objective was to investigate the correlation between normalized lactate load and in-hospital mortality in patients with CS.MethodsData were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database. The calculation of lactate load involved the determination of the cumulative area under the lactate curve, while normalized lactate load was computed by dividing the lactate load by the corresponding period. Receiver Operating Characteristic (ROC) curves were constructed, and the evaluation of areas under the curves (AUC) for various parameters was performed using the DeLong test.ResultsOur study involved a cohort of 1932 CS patients, with 687 individuals (36.1%) experiencing mortality during their hospitalization. The AUC for normalized lactate load demonstrated significant superiority compared to the first lactate (0.675 vs. 0.646, P < 0.001), maximum lactate (0.675 vs. 0.651, P < 0.001), and mean lactate (0.675 vs. 0.669, P = 0.003). Notably, the AUC for normalized lactate load showed comparability to that of the Sequential Organ Failure Assessment (SOFA) score (0.675 vs. 0.695, P = 0.175).ConclusionThe normalized lactate load was an independently associated with the in-hospital mortality among CS patients.

Lactate thresholds and role of nitric oxide in male rats performing a test with forced swimming to exhaustion.

The present study assessed a complex of biochemical parameters at the anaerobic threshold (AT) in untrained male Wistar rats with different times to exhaustion (Tex ) from swimming. The first group of rats was randomly divided into six subgroups and subjected to a swimming test to exhaustion without a load or with a load of 2%-10% of body weight (BW). In the first group, we established that for untrained rats, the load of 4% BW in the swimming to exhaustion test was optimal for endurance assessment in comparison with other loads. The second group of rats went through a preliminary test with swimming to exhaustion at 4% BW and was then divided into two subgroups: long swimming time (LST, Tex > 240 min) and short swimming time (SST, Tex < 90 min). All rats of the second group performed, for 6 days, an experimental training protocol: swimming for 20 min each day with weight increasing each day. We established that the AT was 3% BW in SST rats and 5% BW in LST rats. The AT shifted to the right on the lactate curve in LST rats. Also, at the AT in the LST rats, we found significantly lower levels of blood lactate, cortisol, and NO.

Effect of BNT162b2 mRNA booster vaccination on VO2 max in recreational athletes: A prospective cohort study.

The goal of the present study was to systematically evaluate the effect of a booster vaccination with the BNT162b2 messenger RNA (mRNA;Pfizer-BioNTech®) vaccine on maximum oxygen uptake (VO2 max), potential signs of (peri)myocarditis, and sports participation. Recreational athletes who were scheduled to undergo booster vaccination were evaluated with transthoracic echocardiography, serum measurements of high-sensitivity C-reactive protein(hsCRP) and high-sensitivity troponin I, and a bicycle cardiopulmonary exercise test (CPET) with serum lactate evaluation before the booster vaccine administration. Sevendays postvaccination the test battery was repeated. Additionally, the subjects were asked to fill in a questionnaire on side effects and a subjective evaluation of their relative training volume and intensity as compared to the weeks before vaccination. A group of 42 analysed athletes showed a statistically significant 2.7% decrease in VO2 max after vaccination (mean standard error of mean pre: 48.6 (1.4) ml/kg/min; post: 47.3 (1.4) ml/kg/min; p = 0.004). A potentially clinically relevant decrease of 8.6% or more occurred in 8 (19%) athletes. Other CPET parameters and lactate curves were comparable. We found no serological or echocardiographic evidence of (peri)myocarditis. A slight but significant increase in hsCRP was noted 1 week after vaccination. Side effects were mild and sports participation was generally unchanged or mildly decreased after vaccination. In our population of recreational endurance athletes, booster vaccination with the BNT162b2 mRNA vaccine resulted in a statistically significant decrease in VO2max 7 days after vaccination. The clinical impact hereof needs to be further determined. No major adverse events were observed.

Lactate Threshold Evaluation in Swimmers: The Importance of Age and Method.

The purpose of the study was to define the most appropriate method for the calculation of the speed corresponding to lactate threshold (sLT) in male swimmers. Eight boys and eight adolescents (age: 11.4±0.5 and 15.8±0.8 years) performed 7×200-m swimming front-crawl and after drawing the speed vs. lactate curve, the sLTs were calculated using five methods: i) the intersection of two linear regression lines, ii) visual inspection, iii) D-max, iv) D-max modified, v) intersection of combined linear and exponential regression lines. All methods were compared to the speed corresponding to maximal lactate steady state (sMLSS). Two to four 30-min efforts of continuous swimming at imposed constant pace were used for sMLSS calculation. In both groups, speed of D-max modified was similar to sMLSS (children, 1.061±0.073 vs. sMLSS: 1.071±0.072 m·s-1; p>0.05; effect size: ES=0.15, small; adolescents, 1.318±0.060 vs. sMLSS: 1.284±0.047 m·s-1; p>0.05; ES=0.64, medium). In adolescents, sLT calculated by intersection of two regression lines and by visual inspection presented medium ES (0.22-0.24) and were no different to sMLSS (1.296 ± 0.051, 1.295±0.053 m·s-1, p>0.05). When testing children, D-max modified is the most appropriate method to estimate sMLSS. The intersection of the linear regression lines and visual inspection are suggested for sMLSS determination in adolescents.

Effect of administration of monophasic oral contraceptive on the body composition and aerobic and anaerobic capacities of female athletes.

To examine the effects of administration of monophasic oral contraceptive (OC) on the body composition and aerobic and anaerobic capacities of female athletes. Ten female athletes (23.0 ± 4.1 years old) participated in this study. All the subjects were examined during the menstrual cycle (early follicular [EF], middle luteal [ML]) and OC cycle (inactive OC, and active OC phases). After the menstrual cycle measurements, all the subjects began taking OC. The athletes tested using a body composition, circumferences, the lactate curve test, the maximal oxygen consumption test, and the Wingate test during all phases. Waist circumference was lower during the OC cycle than menstrual cycle (P < 0.05), and the other circumferences of parts were not different during the menstrual or OC cycles. However, there were no differences in body composition before and after taking OC. The phase of the menstrual or OC cycle did not affect maximal oxygen consumption, heart rate max or power output at a blood lactate concentration of 2 and 4 mmol/L between the menstrual and OC cycle phases. Although, the peak blood lactate level after the Wingate test was higher during the OC cycle (inactive OC phase, 13.0 ± 2.4 mmol/L; active OC phase, 12.4 ± 3.0 mmol/L) than during the menstrual cycle (EF phase, 11.9 ± 2.1 mmol/L; ML phase, 11.4 ± 2.1 mmol/L; P < 0.05), the peak and average power in the Wingate test did not change during the menstrual and OC cycle phases. Administration of monophasic OC did not affect the body composition or aerobic and anaerobic capacities of female athletes.

Anaerobic Fitness Testing in Crossfit

Summary CrossFit is one of the sports disciplines where endurance play a significant role in the performance. For testing anaerobic fitness it is important to choose the means that are part of the exercise and have a good transfer to the sport. A sample of competitive crossfitters (n = 12) underwent stress tests on the assault air bike (AB) (60 s) and Wingate. In addition to the performance parameters (Wmax, Wmean, W/kg, cal), lactate values after exercise (1st, 5th, 10th and 15th minute) were monitored. The results showed significant differences in both the absolute values of lactate and the development of the lactate curve (α = 0.05). The correlation of the selected variables showed a significant relationship between the average Watts value and the calories traveled (0.894). Testing anaerobic fitness with AB appears to be a suitable variant for CrossFit, as well as monitoring the development of lactate curve. Due to the original design of the study, it is necessary to verify the results.

Physiological factors which influence the performance potential of athletes: analysis of sports medicine performance testing in Nordic combined

ABSTRACT Background The sports medicine performance diagnostics include investigative procedures that supply information on the performance capacity and stamina of an athlete. This creates a foundation for a personalised training plan and enables optimised control of the training process. Methodology The study population consisted of 24 male Nordic combined athletes from the national German squad. They were monitored using sports medicine over a period of five winter seasons.The test speeds on the treadmill in m/s are determined at lactate values of 2, 3 and 4 mmol/l in the peripheral blood values to calculate the lactate curve. Results The higher the test performance expressed as a percentage, the more likely it was that a top position could be achieved. The individual anaerobic threshold and the maximal oxygen uptake increased significantly with an increase in test performance expressed as a percentage. The older the athlete, the better they performed in the overall world cup. When age increased, the test speed [m/s] at lactate values of 2, 3 and 4 mmol/l also increased, along with the test performance expressed as a percentage, the maximal oxygen uptake and the individual anaerobic threshold. A higher BMI proved advantageous in terms of placement in the individual competitions. Conclusion In this study the test speed at a lactate concentration of 4 mmol/l can be recommended as a robuster, more independent from mathematical models and physiologically more valid parameter for performance diagnostics in professional athletes.

Non-oxidative Energy Supply Correlates with Lactate Transport and Removal in Trained Rowers.

This study aimed to test if the non-oxidative energy supply (estimated by the accumulated oxygen deficit) is associated with an index of muscle lactate accumulation during exercise, muscle monocarboxylate transporter content and the lactate removal ability during recovery in well-trained rowers. Seventeen rowers completed a 3-min all-out exercise on rowing ergometer to estimate the accumulated oxygen deficit. Blood lactate samples were collected during the subsequent passive recovery to assess individual blood lactate curves, which were fitted to the bi-exponential time function: La(t)= [La](0)+A1·(1-e-γ 1 t)+A2·(1-e-γ 2 t), where the velocity constants γ1 and γ2 (min-1) denote the lactate exchange and removal abilities during recovery, respectively. The accumulated oxygen deficit was correlated with the net amount of lactate released from the previously active muscles (r =0.58, P<0.05), the monocarboxylate transporters MCT1 and MCT4 (r=0.63, P<0.05) and γ2 (r=0.55, P<0.05). γ2 and the lactate release rate at exercise completion were negatively correlated with citrate synthase activity. These findings suggest that the capacity to supply non-oxidative energy during supramaximal rowing exercise is associated with muscle lactate accumulation and transport, as well as lactate removal ability.

Effect of practical hyperoxic high-intensity interval training on exercise performance

This study investigated the effect of a practical hyperoxic high-intensity interval training (HIIT) on aerobic and anaerobic exercise capacity. Sixteen male athletes were randomized into 2 groups: normoxic HIIT (NHIIT, n = 8) group or hyperoxic HIIT (HHIIT, n = 8) group and trained for 3 weeks (2 days/week) on a cycle ergometer (2-min intervals, with 2-min rest between intervals) at maximal workload, which was obtained during a maximal graded exercise test under normoxia. All training sessions were performed until exhaustion. Participants performed maximal graded exercise, submaximal exercise, and 90-s maximal exercise tests before and after the training period. Maximal oxygen uptake (P < 0.01) increased significantly in both groups. Blood lactate curve during submaximal exercise improved significantly only in the HHIIT group (P < 0.01). Mean power output during maximal exercise increased significantly only in the HHIIT group (P = 0.02). This study demonstrated that a practical hyperoxic HHIIT might be effective for improving aerobic capacity and anaerobic performance.

Effects of a 6-week additional work on performance capacity: Hints for a parasympathic overtraining?

Introduction. Maximum performance can only be achieved with an optimal balance of training and recovery. Already 15 years ago Jeukendrup & Hesselink (1994) mentioned that hints can be derived from lactate curves concerning a potential overreaching. In this small study we show the effects of a six-week standard infantry military training on performance capacity in young elite orienteers. The potentially induced overreaching and the ingoing alterations of heart rate patterns and lactate answers shall be analysed. Material & Methods. Five young elite orienteers (22.6 ± 0.52 years / 178.4 ± 7.6 cm / 66.4 ± 3.4 kg) completed an exhaustive treadmill test, first at one and a half year before, second at half a year before and third immediately after completing a six-week period of a session of a hard infantry military training. Results. After the six-week additional military training measurements of heart rate decreased at speed 10.8 km/h from 142.6 ± 11.6 to 129.2 ± 11.9 (p = .0192); at speed 12.6 km/h from 153.4 ± 11.4 to 141.2 ± 12.6 (p = .0192); at speed 14.4 km/h from 166.4 ± 10 to 155.4 ± 12.2 (p = .02); at speed 16.2 km/h from 177.4 ± 6.9 to 168.4 ± 6.5 (p = .0244); at speed 18 km/h from 186.2 ± 5.8 to 181.4 ± 3.6 (p = .0313) compared to the measurement half a year earlier. Discussion. We strongly believe that these lower average heart rates for submaximal speed stages cannot be assessed as positive in terms of performance but might be in accordance with a parasympathetic overreaching respectively parasympathetic stimulation. The increased parasympathetic tone probably required a correspondingly stronger sympathetic stimulus for activation, which, however, could not act as efficiently as after normal training conditions as athletes were not rested well yielding to a shift of the heart rate/performance curve in line with findings of Jeukendrup & Hesselink (1994) of lactate curve in cyclists already 15 years ago.

Effects of all-out sprint interval training under hyperoxia on exercise performance.

All‐out sprint interval training (SIT) is speculated to be an effective and time‐efficient training regimen to improve the performance of aerobic and anaerobic exercises. SIT under hypoxia causes greater improvements in anaerobic exercise performance compared with that under normoxia. The change in oxygen concentration may affect SIT‐induced performance adaptations. In this study, we aimed to investigate the effects of all‐out SIT under hyperoxia on the performance of aerobic and anaerobic exercises. Eighteen college male athletes were randomly assigned to either the normoxic sprint interval training (NST, n = 9) or hyperoxic (60% oxygen) sprint interval training (HST, n = 9) group and performed 3‐week SIT (six sessions) consisting of four to six 30‐sec all‐out cycling sessions with 4‐min passive rest. They performed maximal graded exercise, submaximal exercise, 90‐sec maximal exercise, and acute SIT tests on a cycle ergometer before and after the 3‐week intervention to evaluate the performance of aerobic and anaerobic exercises. Maximal oxygen uptake significantly improved in both groups. However, blood lactate curve during submaximal exercise test significantly improved only in the HST group. The accumulated oxygen deficit (AOD) during 90‐sec maximal exercise test significantly increased only in the NST group. The average values of mean power outputs over four bouts during the acute SIT test significantly improved only in the NST group. These findings suggest that all‐out SIT might induce greater improvement in aerobic exercise performance (blood lactate curve) but impair SIT‐induced enhancements in anaerobic exercise performance (AOD and mean power output).

Urine Lactate after Continuous and Interval Cycling Exercise Bouts Eliciting Different Blood Lactate Concentrations

Post-exercise urine lactate (UL) has been suggested as a novel exercise biomarker of lactate production. The few studies examining the association between post-exercise peak blood lactate (BL) and UL have reported moderate to high linear correlations. However, these studies have not considered BL concentration during exercise. Also, the range of BL values was narrow (about 10 mmol/L), thus limiting the predictive value of UL. PURPOSE: To examine the association between UL and BL concentrations during continuous and interval exercise of equal mean power. METHODS: Eleven healthy young males performed four trials in random, counterbalanced order, one week apart. All trials included 20 min of cycling with equal mean power output, performed either continuously (CON) or in the form of interval training including 48 x 10 s (HIIT10), 16 x 30 s (HIIT30), or 8 x 60 s (HIIT60) bouts at a power output corresponding to 100% of VO2max. Recovery intervals during the HIIT trials included cycling at 15% of VO2max for 150% of the exercise bout time. Capillary BL concentration was measured at rest and every 5 min during exercise, and UL concentration was measured in urine samples obtained pre- and 1 hour post-exercise, with controlled hydration. BL and UL results were analyzed using 2-way ANOVA with repeated measures (trial x time). The association between incremental area under the blood lactate curve (BL-AUC) and UL concentration was determined using linear and exponential functions. RESULTS: BL increased compared with baseline in all trials from the first 5 min of exercise (p < 0.01). BL-AUC increased from CON to HIIT10, HIIT30 and HIIT60 (61.7 ± 21.2, 83.4 ± 29.0, 97.8 ± 34.0, 147.4 ± 44.2 mmol/L x min, respectively, p < 0.01). However, post-exercise UL increased from baseline only in HIIT60 (from 1.2 ± 1.0 to 22.5 ± 23.3 mmol/L, p < 0.001). Exercise BL ranged from 3.0 to 17.7 mmol/L, while post-exercise UL ranged from 0.2 to 76.4 mmol/L. The best function describing the BL-AUC and UL relationship was exponential (r = 0.68, p < 0.05). CONCLUSIONS: The lack of increase in UL despite an increase in BL and their exponential association suggest that there may be a threshold above which BL cannot be disposed within the body and is excreted by the kidneys.

Modifications of the Dmax method in comparison to the maximal lactate steady state in young male athletes

ABSTRACTObjective: To investigate the influence of different approaches for first-rise determination on the accuracy of Dmax as an estimate of the maximal lactate steady state (MLSS).Methods: Seventeen male cyclists and 18 male runners with different levels of endurance performance completed graded exercise tests either on a cycle ergometer or treadmill to determine Dmax, calculated by the final data point and five modifications of the first rise in blood lactate concentration. Two or more constant load tests over 30 min were performed to determine MLSS. Differences between the modifications of the first rise in blood lactate concentration as well as the corresponding Dmax variants and MLSS were tested, using one-way repeated measure ANOVA with Bonferroni post-hoc tests, and illustrated, using the Bland–Altman method. The absolute agreement was observed, using intra-class correlation coefficients, based on a single measure, absolute agreement, 2-way mixed effects model.Results: The peak power output/running velocity of the groups averaged 275 ± 43 W and 4.3 ± 0.4 m · s−1, respectively. The mean power output/running velocity at MLSS was 229 ± 38 W and 3.77 ± 0.38 m · s−1. For both running and cycling the original Dmax described by Cheng et al. was significantly lower than MLSS (p < 0.01). All modifications showed good agreement with MLSS (ICC ≥0.75). According to the Bland–Altman method the mean differences of the modifications compared to MLSS in cycling ranged from −7 (43) to 2 (41) W. In running the mean differences ranged from −0.12 (0.34) to −0.08 (0.35) m· s−1.Conclusion: We suggest using the first rise in blood lactate concentration for calculating Dmax instead of the first data point of a lactate curve as originally described. The approach of first rise determination has no substantial influence on the accuracy of Dmax compared to MLSS in cycling and running.

A COMPARISON OF METHODS FOR CALCULATING LACTATE ANAEROBIC THRESHOLDS IN JUDO AND MIXED MARTIAL ARTS ATHLETES

The study aimed to determine the differences between exercise intensities at the anaerobic threshold values (VAT) calculated with methods of lactate curve analysis such as LTvisual, LTloglog, LT4.0, LTΔ1, and LTD-max, and to build regression equations that allow athletic training specialists to compare VAT values obtained from LTvisual, LTloglog, LTΔ1, LTD-max with that calculated with LT4.0. The sample analysed during the study consisted of 19 judoka and 22 MMA practitioners in a preparation period for competition. Each of the two disciplines has its own hierarchy of VAT values. The analysis aimed to determine the effect of the athletic discipline factor and of the method factor on VAT values. Results: The coefficient of variation (CV) values obtained indicate that the effective exercise intensities have bigger variation in judoka aerobic endurance training. VAT values assessed for judoka using different methods for analysing the blood lactate concentration curve are more consistent than in MMA competitors. Conclusions: Judo and MMA competitors have their specific hierarchies of running velocities at the anaerobic threshold, with both the athletic discipline factor and the method factor having an interaction effect on the VAT level. VAT levels assessed from the different methods used to analyse the blood lactate concentration curve are more consistent (ANOM) in judoka than in MMA practitioners.

Mechanism of formate-nitrite transporters by dielectric shift of substrate acidity.

Bacterial formate-nitrite transporters (FNTs) regulate the metabolic flow of small, weak mono-acids. Recently, the eukaryotic PfFNT was identified as the malaria parasite's lactate transporter and novel drug target. Despite crystal data, central mechanisms of FNT gating and transport remained unclear. Here, we show elucidation of the FNT transport mechanism by single-step substrate protonation involving an invariant lysine in the periplasmic vestibule. Opposing earlier gating hypotheses and electrophysiology reports, quantification of total uptake by radiolabeled substrate indicates a permanently open conformation of the bacterial formate transporter, FocA, irrespective of the pH Site-directed mutagenesis, heavy water effects, mathematical modeling, and simulations of solvation imply a general, proton motive force-driven FNT transport mechanism: Electrostatic attraction of the acid anion into a hydrophobic vestibule decreases substrate acidity and facilitates protonation by the bulk solvent. We define substrate neutralization by proton transfer for transport via a hydrophobic transport path as a general theme of the Amt/Mep/Rh ammonium and formate-nitrite transporters.

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.

Deep sea water improves exercise and inhibits oxidative stress in a physical fatigue mouse model.

Physical fatigue is extremely common and occurs daily, and is considered to be associated with oxidative stress. The diverse functions of deep sea water (DSW) have recently gained increasing attention. Previous studies have emphasized the anti-fatigue effect of DSW, but the intrinsic mechanism behind the effect remains to be elucidated. In the imprinting control region (ICR) mice model, DSW delayed the exhaustive swimming time. In addition, DSW decreased the area under the blood lactate (BLA) curve, which was associated with the area under the BLA curve of pre-swimming, post-swimming and post-rest. Furthermore, DSW reduced the basal levels of malondialdehyde and the post-swimming concentration of blood urea nitrogen, lactate dehydrogenase and creatine kinase after swimming, along with an increase in the normal level of antioxidant enzyme activity such as superoxide dismutase and glutathione peroxidase. However, no significant effect on body weight, hepatic glycogen and muscle glycogen was observed between any group. In conclusion, DSW can improve the athletic ability and alleviate physical fatigue of ICR mice. This effect is achieved by enhancing the antioxidant capacity.

Porovnání aktuálních metodik identifikace funkčních a anaerobních prahů na bicyklovém ergometru u triatlonistů

The aim of the study was to compare the currently methodics for identification functional and anaerobic thresholds on a bicycle ergometer by triathletes. The sample included triathletes (men), regular participants in the Czech triathlon cup (n = 10, age 35.89 ± 7.94 years, body height 181.83 ± 6.52 cm, weight 80.65 ± 6.53 kg). In the study, we compared the evaluation methodics using lactate curve, respiratory parameters, theoretical calculation, motor test and Conconi test. For statistical data processing we used the Repeated Measures, for evaluating the significance of differences between each test method then pairwise comparation (Bonferroni test). Results showed statistically significant differences (p = 0.000). Significantly higher values are reached in Conconi test (173 ± 14.2 beats.min–1, 313 ± 74.8 W). In pairwise comparison of methodics are differences between lactate and Conconi test in HR values (p = 0.037) as well as the difference between HR lactate test and theoretical calculation (p = 0.039). Most statistical variations in the watts evaluation is found again in connection with Conconi test (time trial: p = 0.039; lactate test: p = 0.013; spiroergometry: p = 0.041).

Effect of high-dose dexamethasone on perioperative lactate levels and glucose control: a randomized controlled trial.

IntroductionBlood lactate levels are increasingly used to monitor patients. Steroids are frequently administered to critically ill patients. However, the effect of steroids on lactate levels has not been adequately investigated. We studied the effect of a single intraoperative high dose of dexamethasone on lactate and glucose levels in patients undergoing cardiac surgery.MethodsThe Dexamethasone for Cardiac Surgery (DECS) trial was a multicenter randomized trial on the effect of dexamethasone 1 mg/kg versus placebo on clinical outcomes after cardiac surgery in adults. Here we report a pre-planned secondary analysis of data from DECS trial participants included at the University Medical Center Groningen. The use of a computer-assisted glucose regulation protocol—Glucose Regulation for Intensive care Patients (GRIP)—was part of routine postoperative care. GRIP aimed at glucose levels of 4 to 8 mmol/L. Primary outcome parameters were area under the lactate and glucose curves over the first 15 hours of ICU stay (AUC15). ICU length of stay and mortality were observed as well.ResultsThe primary outcome could be determined in 497 patients of the 500 included patients. During the first 15 hours of ICU stay, lactate and glucose levels were significantly higher in the dexamethasone group than in the placebo group: lactate AUC15 25.8 (13.1) versus 19.9 (11.2) mmol/L × hour, P <0.001 and glucose AUC15 126.5 (13.0) versus 114.4 (13.9) mmol/L × hour, P <0.001. In this period, patients in the dexamethasone group required twice as much insulin compared with patients who had received placebo. Multivariate and cross-correlation analyses suggest that the effect of dexamethasone on lactate levels is related to preceding increased glucose levels. Patients in the placebo group were more likely to stay in the ICU for more than 24 hours (39.2%) compared with patients in the dexamethasone group (25.0%, P = 0.001), and 30-day mortality rates were 1.6% and 2.4%, respectively (P = 0.759).ConclusionsIntraoperative high-dose dexamethasone increased postoperative lactate and glucose levels in the first 15 hours of ICU stay. Still, patients in the dexamethasone group had a shorter ICU length of stay and similar mortality compared with controls.Trial registrationClinicalTrials.gov NCT00293592. Registered 16 February 2006.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0736-9) contains supplementary material, which is available to authorized users.