Blood Lactate Levels Research Articles

Methods to characterize lactate turnover in aging and Alzheimer's disease; The LEAN study

BackgroundThere is evidence that chronic exercise can benefit the brain, but the effects vary markedly between studies. One potential mechanism for exercise-related benefit is the increase in systemic lactate concentration that is well-characterized to occur during exercise. Lactate is known to cross the blood brain barrier and can be used readily as a fuel for neurons. This may be particularly important in Alzheimer's Disease, which is characterized by cerebral hypometabolism. However, little is known about how whole-body lactate metabolism differs between older adults and individuals with cognitive impairment. This information is critical when considering potential differences in responses to exercise in various cognitive diagnosis groups. MethodsHere we describe the use of a “lactate clamp” procedure to adjust blood lactate levels to approximate those achieved during exercise, but while at rest. This trial will compare lactate oxidation between cognitively healthy older adults and cognitively impaired participants. We will further evaluate the effect of acute lactate infusion on cognitive performance. DiscussionThe findings of the study described here, the Lactate for Energy and Neurocognition trial (clinicaltrials.gov # NCT05207397) will add to our understanding of systemic lactate mechanics in cognitively healthy older adults and individuals with Alzheimer's Disease. These findings will be applicable to ongoing exercise trials and to future studies aimed at modulating systemic bioenergetic function in aging and Alzheimer's Disease.

Examining the acute cardiovagal consequences of supine recovery during high-intensity interval exercise.

Exercise training requires the careful application of training dose to maximize adaptation while minimizing the risk of illness and injury. High-intensity interval training (HIIT) is a potent method for improving health and fitness but generates substantial autonomic imbalance. Assuming a supine posture between intervals is a novel strategy that could enhance physiological readiness and training adaptations. This study aimed to establish the safety and feasibility of supine recovery within a HIIT session and explore its acute effects. Fifteen healthy, active males (18-34years) underwent assessment of cardiopulmonary fitness. Participants completed two identical HIIT treadmill sessions (4 x [3min at 95% VO2max, 3min recovery]) employing passive recovery in standing (STANDard) or supine (SUPER) posture between intervals. Heart rate variability (HRV), HRV recovery (HRVrec; lnRMSSD) and heart rate recovery at 1min (HRrec) were assessed using submaximal constant speed running tests (CST) completed prior to, immediately after and 24h following HIIT. No severe adverse events occurred with SUPER, and compliance was similar between conditions (100 ± 0%). The change in HRVrec from the CST pre-to-post-HIIT was not different between conditions (p = 0.38); however, HRrec was faster following SUPER (39 ± 7bpm) vs. STANDard (36 ± 5bpm). HRV 24h post-SUPER was also greater (3.56 ± 0.57ms) compared to STANDard (3.37 ± 0.42ms). Despite no differences in perceived exertion (p = 0.23) and blood lactate levels (p = 0.35) between SUPER and STANDard, average running HRs were lower (p = 0.04) with SUPER (174 ± 7bpm) vs. STANDard (176 ± 7bpm). Supine recovery within HIIT attenuates acute cardioautonomic perturbation and accelerates post-exercise vagal reactivation. SUPER enhances recovery of vagal modulation, potentially improving physiological preparedness 24h post-HIIT. Further research exploring the chronic effects of SUPER are now warranted.

Blood lactate in children with starged inguinal hernia

Target. To study the level of blood lactate in children with strangulated inguinal hernias (SIH). Material and methods. 46 boys with UPG under the age of 3 years were examined. The examination included anamnesis, examination, laboratory data, including blood lactate, ultrasound, Doppler sonography, examination of biopsy and surgical material. Results. Blood lactate in children of group 1 (up to 12 hours from the moment of strangulation) was 1.8±0.3 mmol/l, in children of group 2 (from 12 to 24 hours) - 2.5±0.2 mmol/l, in children of group 3 (after 24 hours) - 2.8±0.3 mmol/l. All children were operated on. In 6 children, bowel resection was performed; in 6, testicular infarction was detected. Discussion. A significant excess of normal blood lactate levels occurred in children with strangulated inguinal hernias who were admitted later than 12 hours from the moment of strangulation. Conclusion. The study of blood lactate in children with strangulated inguinal hernias can be used in the diagnosis of intestinal and testicular ischemia.

Comparison of predictors of survival among fulminant myocarditis patients undergoing veno-arterial extracorporeal membrane oxygenation in the adult and pediatric populations

Background: Fulminant myocarditis (FM) is a potentially life-threatening disease that requires emergency care. Our study aims to explore clinical outcomes and predictors of survival when using veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support for the treatment of FM in adult and pediatric patients to analyze differences between both populations. Methods: PubMed, Scopus, Web of Science, and Cochrane databases were searched for studies reporting the effect of VA-ECMO on patients diagnosed with fulminant myocarditis. Statistical analysis was performed using R version 4.2.2. Results: Forty-three studies were included in our analysis with a total of 1,268 patients. Survival rates were 65% and 71% among adult and pediatric patients, respectively. Patients who didn’t suffer from cardiac arrest prior to VA-ECMO had better chances of survival in both populations; adults (OR 0.44; P<0.01) and pediatric (OR = 0.32; P= 0.006). Younger age was associated with higher survival among the adults (MD= -8.81; P<0.01). Additionally, pre-ECMO LVEF was higher among survivors in the pediatric group (MD= 8.23; P<0.01). Furthermore, no significant association was detected between sex, VA-ECMO duration, systolic blood pressure, lactate levels, and survival rates among both groups. Conclusion: Using VA-ECMO in patients with fulminant myocarditis can significantly improve survival outcomes, with improved prognosis observed with younger age among adults and absence of prior history of cardiac arrest in both groups.

Dosimetry model for photobiomodulation based on anthropometric and hemodynamic variables in patients with orofacial pain post-Covid-19: Study protocol for randomized clinical trial.

Orofacial pain and tension headache are symptoms that affect a large portion of the population, compromising productivity, social ability, and functional development. The treatment for reducing painful sensation should be chosen carefully, as pharmacological treatment may bring side effects and overload the organism of patients in pain. Low-level laser therapy has been used with local and systemic [vascular] applications for pain control. However, there is still uncertainty in the literature about the ideal dosimetric parameters for photobiomodulation treatment according to patient characteristics. The objective of this project is to validate a dosimetry model based on the relationship between the effects of photobiomodulation with anthropometric and hemodynamic variables, both in local application and systemic application in patients with symptoms of orofacial pain and tension headache. For this purpose, 180 participants with orofacial pain post-covid eligible participants will be randomly assigned to Group 1-Local Photobiomodulation, Group 2-Vascular Photobiomodulation, Group 3-Placebo Local Photobiomodulation, or Group 4-Placebo Vascular Photobiomodulation [Therapy EC-DMC device, São Carlos, Brazil,- 660 nm, 100mW] using stratified block randomization. Before the application, sociodemographic information such as age, skin phototype [classified by the Fitzpatrick scale], weight, height, body mass index [BMI], oxygen saturation [SaO2], blood pressure [BP], heart rate [HR], and thickness of skin, fat, and facial muscles will be collected. During the application, we will collect local temperature, SaO2, BP, and HR. Before and after laser application, blood levels of lactate and hemoglobin, BP, and HR will be measured in the first and last session. In addition to demographic, anthropometric, and hemodynamic variables, the penetrated energy will be quantified using a power meter, and information from orofacial pain and headache symptom questionnaires will be analyzed. The Monte Carlo simulation technique will be used to systematically study the relationship between the light penetration profile into the target tissues and the most relevant variables, namely BMI, tissue layer thicknesses, and skin phototype. Light transmittance, measured in vivo and simulated, will be compared to validate a personalized dosimetry model. The results of this study contribute to validating a Monte Carlo Simulation model to calculate the appropriate dosimetry for photobiomodulation therapies in the control of patients with Post-Covid-19 orofacial pain. Trial registration number: NCT06065969.

Effect of acute supplementation of hibiscus-ginger drink on university athletes’ aerobic power and blood lactate

Background: Sport training places significant demand on athletes, motivating them to seek strategies to enhance performance and maintain competitiveness. The use of ergogenic aids has become prevalent in sport, although not without potential risks. Hibiscus-ginger juice, rich in vitamins and minerals, has been suggested to improve metabolism, aid in post-exercise recovery, reduce inflammation, and enhance athletic performance. Aims: This study aimed to investigate the effect of hibiscus ginger juice supplementation on aerobic power and blood lactate levels in athletes. Methods: A pretest-posttest experimental design was employed, involving 28 university athletes aged 20 – 37 years. Participants were randomly assigned to a treatment group receiving 500 mL of hibiscus-ginger juice daily after training for 24 days, or a control group. Physiological measures of blood lactate levels and aerobic power were assessed on three separate occasions during the study period. Results: Mixed model ANOVA showed no significant differences in blood lactate levels (p = .502) or aerobic power (p = .117). Daily consumption of 500 mL of hibiscus-ginger juice for 24 days did not significantly alter aerobic power or blood lactate levels of athletes. Conclusion: The findings suggest that consuming hibiscus-ginger juice may not provide a performance advantage for athletes compared to those who do not. Keywords: Acute supplementation, aerobic power, blood lactate level, hibiscus-ginger juice, university athletes.

Efficacy and safety of inhaled molecular hydrogen therapy in patients with respiratory failure due to chronic obstructive pulmonary disease exacerbation in post-COVID period

Molecular hydrogen (H2) is a powerful antioxidant and anti-apoptotic agent. H2 has been studied in a number of clinical studies in the recent years.The aim of this research was to investigate the efficacy and safety of H2 inhalation therapy in patients with hypoxemic and hypercapnic respiratory failure (RF) against exacerbation of chronic obstructive pulmonary disease (COPD) in the post-COVID (Corona Virus Disease 2019) period.Methods. The randomized prospective parallel comparative study included patients (n = 60: 40 men aged 71.2 ± 1.8 years, 20 women aged 70.9 ± 2.8 years) with a post-COVID-19 exacerbation of COPD complicated by hypoxemic/hypercapnic RF. The patients were divided into 2 groups: group 1 (main) (n = 30: 18 men, 12 women), group 2 (control) (n = 30: 18 men, 12 women). To maintain arterial blood saturation ≥ 90 %, patients in both groups received respiratory support (non-invasive ventilation) using the Prisma 25ST device (Lowenstein Medical, Germany) in the BiPAP S/T mode (BiLevel Positive Airway Pressure Spontaneous/Time spontaneous/forced mode 20–24/4–6 cm H2O and O2, respectively; the fractional oxygen concentration in the inhaled gas mixture was ≥ 24%). In addition to standard treatment, patients in the main group received additional H2 therapy (Suisonia device, Japan) through a nasal cannula for 90 minutes daily for 14 days.Results. In patients of the main group, a decrease in the stiffness index was detected from 14.6 ± 1.2 to 6.2 ± 0.6 m/s, and the arterial blood lactate level – from 2.84 ± 0.1 to 0.02 ± 0.1 mmol/l (p < 0.001), the calculated shunt fraction Qs/Qt (venous admixture) – from 27.21 ± 3.4 to 7.14 ± 1.23 (p < 0.01) and an increase in the following parameters: reflection index – from 42.2 ± 2.0 to 66.2 ± 4.9% (p < 0.05), virus-specific IgG level – from 134 ± 125 to 669 ± 164 (p < 0. 05), blood flow velocity in arterioles – from 473 ± 108 to 868 ± 64 μm/s (p < 0.05), blood flow velocity in venules – from 299 ± 56 to 862 ± 69 μm/s (p < 0.05), the 6-minute walk distance – from 57.1 ± 4.4 to 328.9 ± 33.7 m (p < 0.05).Conclusion. H2 inhalations were safe and increased the therapeutic effect when added to standard therapy for patients with hypoxemic and hypercapnic RF during exacerbation of COPD in the post-COVID period.

Agreement Between Heart Rate Variability - Derived vs. Ventilatory and Lactate Thresholds: A Systematic Review with Meta-Analyses.

Determining thresholds by measuring blood lactate levels (lactate thresholds) or gas exchange (ventilatory thresholds) that delineate the different exercise intensity domains is crucial for training prescription. This systematic review with meta-analyses aims to assess the overall validity of the first and second heart rate variability - derived threshold (HRVT1 and HRVT2, respectively) by computing global effect sizes for agreement and correlation between HRVTs and reference - lactate and ventilatory (LT-VTs) - thresholds. Furthermore, this review aims to assess the impact of subjects' characteristics, HRV methods, and study protocols on the agreement and correlation between LT-VTs and HRVTs. Systematic computerised searches for studies determining HRVTs during incremental exercise in humans were conducted. The agreements and correlations meta-analyses were conducted using a random-effect model. Causes of heterogeneity were explored by subgroup analysis and meta-regression with subjects' characteristics, incremental exercise protocols, and HRV methods variables. The methodological quality was assessed using QUADAS-2 and STARDHRV tools. The risk of bias was assessed by funnel plots, fail-safe N test, Egger's test of the intercept, and the Begg and Mazumdar rank correlation test. Fifty included studies (1160 subjects) assessed 314 agreements (95 for HRVT1, 219 for HRVT2) and 246 correlations (82 for HRVT1, 164 for HRVT2) between LT-VTs and HRVTs. The standardized mean differences were trivial between HRVT1 and LT1-VT1 (SMD = 0.08, 95% CI -0.04-0.19, n = 22) and between HRVT2 and LT2-VT2 (SMD = -0.06, 95% CI -0.15-0.03, n = 42). The correlations were very strong between HRVT1 and LT1-VT1 (r = 0.85, 95% CI 0.75-0.91, n = 22), and between HRVT2 and LT2-VT2 (r = 0.85, 95% CI 0.80-0.89, n = 41). Moreover, subjects' characteristics, type of ergometer, or initial and incremental workload had no impact on HRVTs determination. HRVTs showed trivial differences and very strong correlations with LT-VTs and might thus serve as surrogates. These results emphasize the usefulness of HRVTs as promising, accessible, and cost-effective means for exercise and clinical prescription purposes.

Wheat Peptides as Catalysts for Athletic Performance Improvement in Cross-Country Skiers: A Randomized Controlled Trial.

This study investigated the efficacy of wheat peptide supplementation compared to regular proteins in elite cross-country skiers, providing insights into the metabolic and performance effects of these supplements in order to guide athletes in selecting optimal energy sources for training and competition. Nineteen healthy male cross-country skiers were enrolled and assigned to either the peptide group (PEP, n = 9) or the protein group (PRO, n = 10). A four-week intervention study involving supplementation with wheat peptides/regular proteins was conducted, and pre- and post-intervention assessments were performed to evaluate exercise capacity and metabolic profiles. The study found that the PEP group and the PRO group showed distinct within-group effects on exercise performance. The PEP group demonstrated improved aerobic capacity, including better performance in 10 km roller skating, an increased lactate threshold, and reduced resting blood lactate levels. The PRO group enhanced anaerobic capacity, such as improved sprint time, hexagon test performance, and lactate clearance. Metabolomic analysis revealed specific metabolic pathways affected in each group, with the PEP group showing impacts on the α-linolenic acid pathway and the PRO group on ketone body synthesis and degradation as well as vitamin B6 metabolism. Our findings indicate that wheat oligopeptides and regular proteins have comparable effects on exercise performance. However, the wheat peptides may offer greater advantages in enhancing aerobic capacity. No significant variations were observed in blood metabolite profiles between the two groups, but distinct metabolic pathways exhibited different responses.

First postnatal lactate blood levels on day 1 and outcome of preterm infants with gestational age

Serum lactate levels are used as biomarkers for perinatal asphyxia, while their value for outcome prediction in preterm infants is uncertain. It was the aim of this observational study to determine the association of the first postnatal serum-lactate levels on day 1 of life and short-term outcome in preterm infants less than 29 gestational weeks. We analysed data in a population-based cohort of German Neonatal Network (GNN) preterm infants with available first postnatal lactate levels enrolled at 22-28 weeks of gestational age (GA) between 1st of April 2009 and 31st December 2020. We hypothesized that high lactate levels as measured in mmol/L increase the risk of intraventricular haemorrhage (IVH) and bronchopulmonary dysplasia (BPD) in infants with VLBW regardless of small-for-gestational-age (SGA) status. Hypotheses were evaluated in univariate analyses and multiple logistic regression models. First postnatal lactate levels were available in 2499 infants. The study population had a median GA of 26.7 [IQR 25.2-27.9] weeks and birth weight of 840 g [IQR 665-995]. Infants with short-term complications such as IVH and BPD had higher initial lactate levels than non-affected infants. The positive predictive value of a lactate cut-off of 4 mmol/L was 0.28 for IVH and 0.30 for BPD. After adjustment for known confounding variables, each 1 mmol/L increase of day 1 lactate levels was associated with a modestly increased risk of IVH (OR 1.18; 95% CI 1.03-1.37; p = 0.002) and BPD (OR 1.23; 95% CI 1.06-1.43; p = 0.005) but not with sepsis or mortality. Notably, SGA was associated with lower risk of any grade and severe IVH (OR 0.70; 95% CI 0.54-0.85; p = 0.001). In our observational cohort study higher initial lactate levels were associated with adverse outcome regardless of SGA status. However, the predictive value of lactate cut-off levels such as 4 mmol/L is low.

Predictive analysis of lactate clearance on the prognosis of patients with large burns

Aims: To examine burn shock monitoring and the connection between lactate clearance and shock prognosis in individuals with severe burns. Materials and methods: This retrospective analysis comprised 100 patients with significant burns treated in our hospital between August 2017 and August 2021. The patients were split into two groups based on whether they survived or not: 50 cases each in the survival and death groups. Both groups had their blood lactate levels, partial pressure of oxygen, and other relevant indices tested. Analysis was done on the correlation between lactate level, lactate clearance, and death as well as the association between lactate clearance and prognosis at each time and point. Results: The lactate clearance rates at 6 h, 12 h, 24 h and 24 h in the survival group were greater than those in the death group, and the differences were significant (p < 0.05). The lactate clearance rates at each time point were compared at a cut-off of 20%, and patients with 6 h and 12 h blood lactate clearance rates ≥20.0% had lower prognostic morbidity and mortality rates than those <20.0%, with a significant difference (p < 0.05). Conclusion: Lactate clearance is directly correlated with the prognosis of patients with severe burns, and survivors also have a high clearance rate. As a result, in patients with severe burns, lactate clearance monitoring during the shock phase can improve prognostic prediction and enable early treatment plan modification based on outcomes.

Predicting mortality of pulmonary thromboembolism in cancer patients with a new scoring system: mPESI

Purpose: Although the Pulmonary Embolism Severity Index (PESI) is frequently used, assessing the severity of pulmonary thromboembolism in cancer patients is not sufficient for prognostic evaluation. In this study, we aimed to designate a scoring system to determine the prognosis of newly diagnosed pulmonary thromboembolism in adult cancer patients. Materials and Methods: This prospective, cross-sectional, and descriptive study was held in an emergency department of a university hospital. Patients were classified according to their PESI scores. The echocardiography results, blood gas analyses, lactate, d-dimer, and N-terminus pro-Brain natriuretic peptide levels of the patients were evaluated to prognosticate mortality. Results: Among 53 patients included, 13 mortalities occurred. The mortality was 38.8% (5/23) in PESI Class 3, 7.7% (1/12) in PESI Class 4, and 53.8% (7/10) in PESI Class 5 while none in the 8 patients in PESI Class 2. The mortality in the first 24 hours was 23%, 53.9% in the first month, and 23.1% in 1-3 months. According to the cut-off values determined, a scoring called ‘mPESI’ was developed by giving one point each for d-dimer >24.28 µg/mL, N-terminus pro-Brain natriuretic peptide >1340 pg/mL, blood pH

Effects of Different Eccentric Cycling Intensities on Brachial Artery Endothelial Shear Stress and Blood Flow Patterns

ABSTRACT Eccentric exercise has gained attention as a novel exercise modality that increases muscle performance at a lower metabolic demand. However, vascular responses to eccentric cycling (ECC) are unknown, thus gaining knowledge regarding endothelial shear stress (ESS) during ECC may be crucial for its application in patients. The purpose of this study was to explore ECC-induced blood flow patterns and ESS across three different intensities in ECC. Eighteen young, apparently healthy subjects were recruited for two laboratory visits. Maximum oxygen consumption, power output, and blood lactate (BLa) threshold were measured to determine workload intensities. Blood flow patterns in the brachial artery were measured via ultrasound imaging and Doppler on an eccentric ergometer during a 5 min workload steady exercise test at low (BLa of 0–2 mmol/L), moderate (BLa 2–4 mmol/L), and high intensity (BLa levels > 4 mmol/L). There was a significant increase in the antegrade ESS in an intensity-dependent manner (baseline: 44.2 ± 8.97; low: 55.6 ± 15.2; moderate: 56.0 ± 10.5; high: 70.7 ± 14.9, all dynes/cm2, all p values < 0.0002) with the exception between low and moderate and Re (AU) showed turbulent flow at all intensities. Regarding retrograde flow, ESS also increased in an intensity-dependent manner (baseline 9.72 ± 4.38; low: 12.5 ± 3.93; moderate: 15.8 ± 5.45; high: 15.7 ± 6.55, all dynes/cm2, all p values < 0.015) with the exception between high and moderate and Re (AU) showed laminar flow in all intensities. ECC produced exercise-induced blood flow patterns that are intensity-dependent. This suggests that ECC could be beneficial as a modulator of endothelial homeostasis.

The Impact of Different Telerehabilitation Methods on Peripheral Muscle Strength and Aerobic Capacity in COPD Patients: A Randomized Controlled Trial.

Lung diseases have profound effects on the aging population. We aimed to hypothesize and investigate the effect of remote pulmonary telerehabilitation and motor imagery (MI) and action observation (AO) methods on the clinical status of elderly chronic obstructive pulmonary disease (COPD) patients. Twenty-six patients were randomly assigned to pulmonary telerehabilitation (PtR) or cognitive telerehabilitation (CtR) groups. The programs were carried out 3 days a week for 8 weeks. The 6-min walk test (6MWT), modified Medical Research Council dyspnea score, blood lactate level (BLL), measurement of peripheral muscle strength (PMS), and electromyography activation levels of accessory respiratory muscles were the main outcomes. There was a statistically significant improvement (p < 0.05) in both groups in the 6MWT distance and in secondary results, except for BLL. Generally, in the mean muscle activity obtained from the electromyography measurement after the program, there were statistically significant increases in the PtR group and decreases in the CtR group (p < 0.05). There was a statistically significant increase in PMS in both groups. An active muscle-strengthening program has the same benefits as applying the muscle-strengthening program to the patient as MI and AO. CtR can be a powerful alternative rehabilitation method in respiratory patients who cannot tolerate active exercise programs.

Effects of time-dependent acupuncture on back muscle endurance in women with chronic nonspecific low back pain: A randomized crossover trial.

Chronic nonspecific low back pain (CNLBP) is a leading cause of disability and remains a major burden for many public health systems. Acupuncture is a nonpharmacological treatment for CNLBP that can be effective in improving low back pain; nevertheless, its effect on improving back muscle endurance in patients with CNLBP and its duration of effect have not been studied. The goal of this study was to assess the impact of acupuncture on lower back muscle activity in CNLBP patients. This was a single-blind, randomized, crossover experimental study. Thirty female patients were randomized into Group A (15 patients) or Group B (15 patients). Patients in Group A were assigned to receive real acupuncture (RA) in the first phase and sham acupuncture (SA) in the second phase, while those in Group B received SA first and then RA, with a 1-week washout period between phases. Two-way repeated ANOVA was used to evaluate the effect of group and time on isokinetic parameters, Surface electromyography (sEMG) data, and blood data. Significant interaction effects were identified between group * time on the isokinetic parameters of the lumbar extensor muscles, sEMG values of the erector spinae, blood lactate levels, and blood ammonia levels (all p< 0.05). Compared with those of the SA group, the isokinetic parameters of the lumbar extensor muscles, sEMG values of the erector spinae, blood lactate levels, and blood ammonia levels of the RA group were significantly different (all p< 0.05). RA improves lumbar extensor endurance in patients with CNLBP and lasts approximately 9 minutes. RA can improve blood circulation to reduce blood lactic acid and blood ammonia produced during exercise.

Acute exercise alters brain glucose metabolism in aging and Alzheimer's disease.

There is evidence that aerobic exercise improves brain health. Benefits may be modulated by acute physiological responses to exercise, but this has not been well characterized in older or cognitively impaired adults. The randomized controlled trial 'AEROBIC' (NCT04299308) enrolled 60 older adults who were cognitively healthy (n=30) or cognitively impaired (n=30) to characterize the acute brain responses to moderate [45-55% heart rate reserve (HRR)] and higher (65-75% HRR) intensity acute exercise. Each participant received two fluorodeoxyglucose positron emission tomography (FDG-PET) scans, one at rest and one following acute exercise. Change in cerebral glucose metabolism from rest to exercise was the primary outcome. Blood biomarker responses were also characterized as secondary outcomes. Whole grey matter FDG-PET standardized uptake value ratio (SUVR) differed between exercise (1.045±0.082) and rest (0.985±0.077) across subjects [Diff=-0.060, t(58)=13.8, P<0.001] regardless of diagnosis. Exercise increased lactate area under the curve (AUC) [F(1,56)=161.99, P<0.001] more in the higher intensity group [mean difference (MD)=97.0±50.8] than the moderate intensity group (MD=40.3±27.5; t=-5.252, P<0.001). Change in lactate AUC and FDG-PET SUVR correlated significantly (R2=0.179, P<0.001). Acute exercise decreased whole grey matter cerebral glucose metabolism. This effect tracked with the systemic lactate response, suggesting that lactate may serve as a key brain fuel during exercise. Direct measurements of brain lactate metabolism in response to exercise are warranted. KEY POINTS: Acute exercise is associated with a drop in global brain glucose metabolism in both cognitively healthy older adults and those with Alzheimer's disease. Blood lactate levels increase following acute exercise. Change in brain metabolism tracks with blood lactate, suggesting it may be an important brain fuel. Acute exercise stimulates changes in brain-derived neurotrophic factor and other blood biomarkers.

Effect of high-intensity interval training and moderate-intensity continuous training on blood lactate clearance after high-intensity test in adult men.

This study compared the effects of High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on blood lactate clearance. 21 adult males were equally and randomly assigned to the HIIT and MICT groups, and completed 8weeks of training. Before the training intervention, after 4weeks and 8weeks of training, all subjects were tested for blood lactate levels between 0 and 55min after the same high-intensity test. The results show that after 8weeks, blood lactate levels were significantly lower than pre-tests in both the HIIT and MICT groups at "0-55min" after high-intensity test (p < 0.05), and the blood lactate clearance percentage at15-min and 30-min in both groups were significantly higher than the pre-tests (P < 0.01). The blood lactate levels in the HIIT group were significantly lower than those in the MICT group at 15min and 30min after test (P < 0.05), and the blood lactate clearance percentage at 30min in the HIIT group was significantly higher than those in the MICT group (P < 0.05). In conclusion, both HIIT and MICT enhance blood lactate clearance in adult males post high-intensity test, with HIIT demonstrating superior effectiveness, making it a viable alternative to MICT.

6'-Sialyllactose Alleviates Muscle Fatigue through Reduced Blood Lactate Level after Treadmill Exercise in Mice.

6'-Sialyllactose (6'-SL), found in human breast milk, exhibits anti-inflammatory, immune function-enhancing, brain development-promoting, and gut health-improving effects. However, its effects on muscle fatigue remain unknown. Here, we aimed to investigate the effects of 6'-SL on blood lactate level, muscle fiber type, and oxidative phosphorylation protein complexes (OXPHOS) in muscle after exercise using C57BL/6J male mice. C57BL/6J mice were randomly assigned to control or 100 mg/kg 6'-SL. After 12 weeks of 6'-SL administration, the mice were made to perform treadmill exercise; their blood lactate and glucose levels were measured at the basal level (rest) and 0, 5, and 10 min after treadmill exercise. Results showed that 6'-SL treatment in C57BL/6J mice significantly reduced blood lactate level and improved blood glucose level. Moreover, 6'-SL increased the expression of slow-myosin heavy chain (MHC) and OXPHOS in gastrocnemius muscle. In addition, 6'-SL treatment for 12 weeks did not affect food intake, serum biomarkers of tissue injury, and lipid profiles compared with those of the controls. These findings indicate that non-toxic 6'-SL suppressed muscle fatigue during exercise by promoting protein expression of muscle fibers, especially slow-twitch muscle fibers characterized by abundant OXPHOS complexes and decreased blood lactate level. This study suggests that 6'-SL holds promise as a nutritional supplement in exercise and clinical settings, subject to further validation.

The Effect of Surgical Mask Use on Recovery Heart Rate During Gradually Increasing Walking

The World Health Organization (WHO) and the Ministry of Health recommend distance, hygiene, and the use of masks in the fight against epidemics. Therefore, everyone from children to the elderly, from healthy people to all individuals with chronic diseases must wear a mask while performing their daily activities. After the activities they perform at a slow or fast rhythm, they rest in a mask. Therefore, the study aimed to examine the effect of surgical mask use on recovery heart rate during gradually increasing walking. Nine healthy university students without chronic diseases and orthopedic disorders participated in the study voluntarily. Participants performed a gradually increasing walking protocol on a treadmill with and without surgical masks on two different days at least 48 hours apart, and then recovered in a sitting position for 10 minutes, again with and without masks. Data on body temperature, blood pressure (BP), blood lactate level (LA), heart rate (HR), total quality of recovery (TQR), and borg-breathlessness (B-B) were collected. No statistically significant differences were found between unmasked and masked body temperature, lactate level, systolic and diastolic blood pressure, mean recovery HR, end-of-recovery HR, and total heart rate. On the other hand, breathlessness was felt more in masked recovery compared to unmasked recovery and total quality of recovery was felt lower. As a result; it can be said that the use of surgical masks during gradually increasing walking affects the participants psychologically, although it does not affect them physiologically in recovery.

Relationships of Jugular Bulb Parameters with Cerebral Perfusion and Metabolism After Resuscitation from Cardiac Arrest: A Post-Hoc Analysis of Experimental Studies Using a Minipig Model.

Cerebral blood flow (CBF) decreases in the first few hours or days following resuscitation from cardiac arrest, increasing the risk of secondary cerebral injury. Using data from experimental studies performed in minipigs, we investigated the relationships of parameters derived from arterial and jugular bulb blood gas analyses and lactate levels (jugular bulb parameters), which have been used as indicators of cerebral perfusion and metabolism, with CBF and the cerebral lactate to creatine ratio measured with dynamic susceptibility contrast magnetic resonance imaging and proton magnetic resonance spectroscopy, respectively. We retrospectively analyzed 36 sets of the following data obtained during the initial hours following resuscitation from cardiac arrest: percent of measured CBF relative to that at the prearrest baseline (%CBF), cerebral lactate to creatine ratio, and jugular bulb parameters, including jugular bulb oxygen saturation, jugular bulb lactate, arterial-jugular bulb oxygen content difference, cerebral extraction of oxygen, jugular bulb-arterial lactate content difference, lactate oxygen index, estimated respiratory quotient, and arterial-jugular bulb hydrogen ion content difference. Linear mixed-effects models were constructed to examine the effects of each jugular bulb parameter on the %CBF and cerebral lactate to creatine ratio. The arterial-jugular bulb oxygen content difference (P = 0.047) and cerebral extraction of oxygen (P = 0.030) had a significant linear relationship with %CBF, but they explained only 12.0% (95% confidence interval [CI] 0.002-0.371) and 14.2% (95% CI 0.005-0.396) of the total %CBF variance, respectively. The arterial-jugular bulb hydrogen ion content difference had a significant linear relationship with cerebral lactate to creatine ratio (P = 0.037) but explained only 13.8% (95% CI 0.003-0.412) of the total variance in the cerebral lactate to creatine ratio. None of the other jugular bulb parameters were related to the %CBF or cerebral lactate to creatine ratio. In conclusion, none of the jugular bulb parameters appeared to provide sufficient information on cerebral perfusion and metabolism in this setting.