The purpose of this study was to determine if changes in heart rate variability during incremental exercise could be used to estimate lactate threshold and ventilatory threshold in healthy adults. Twenty-four adults performed graded maximal cycle ergometry to volitional fatigue. Blood lactate, heart rate, RR interval, and respiratory gas exchange ...

PURPOSE: Increased blood lactate concentration has been suggested as a primary stimulus for the exercise-induced growth hormone response (EIGR). Patients with McArdle disease are unable to produce lactate in response to exercise and thus offer a unique model to assess the role of lactate in the EIGR. Accordingly, McArdle's patients ...

Chronic kidney disease (CKD) is highly prevalent, with increasing numbers of patients affected by the disease world-wide, and anemia is a common finding in patients with CKD. Anemia impacts negatively on cardiovascular disease, exercise capacity, and quality of life, resulting in significant mortality and morbidity. The aim of this study ...

BACKGROUND/OBJECTIVE: The aim of the present study was to compare blood lactate elimination between individuals with paraplegia (P) and able-bodied (AB) individuals after strenuous arm exercise. METHODS: Eight P and 8 AB men (matched for age, height, and weight) participated in this study. Average weekly arm-training volume for P participants ...

Growing evidence suggests that physiological responses during exercise in sickle cell trait (SCT) carriers might differ from persons with normal haemoglobin. Epidemiological and experimental results support the view that SCT carriers could be advantaged in certain anaerobic activities, but the underlying physiological and bio-cellular mechanisms remain unknown. Maximal aerobic physical ...

A new group of quaternary ammonium lactate based ionic liquids have been prepared and characterized. Didecyldimethylammonium (DDA) and benzalkonium (BA) D,L- and L-lactates are air-stable, hydrophilic, surface-active salts. They are very effective antibacterial and antifungal agents, especially the DDA lactates, against Streptococcus mutants and Candida albicans. Their activities are comparable ...

The aim of this study was to examine the effects of active versus passive recovery on blood lactate disappearance and subsequent maximal performance in competitive swimmers. Fourteen male swimmers from the University of Virginia swim team (mean age 20.3 years, s= 4.1; stature 1.85 m, s= 2.2; body mass 81.1 ...

The intensity of exercise above which oxygen uptake (Vo2) does not account for all of the required energy to perform work has been associated with lactate accumulation in the blood (lactate threshold, LT) and elevated carbon dioxide output (gas exchange threshold). An increase in hydrogen ion concentration ([H+]) is approximately ...

OBJECTIVE: The purpose of this study was to measure physiological responses during exercise performed until exhaustion at the exercise intensity corresponding to the maximal lactate steady state (MLSS) in order to determine why subjects stopped. METHODS: Eleven male trained subjects performed a test at MLSS on a cycle ergometer until ...

PURPOSE: This study looked at the physiological effects of performance in Highland-dance competition to consider whether the traditional methods used during class and rehearsal provide an appropriate training stimulus toward this performance. METHODS: Nine championship standard, female Highland dancers (age 14.2 +/- 1.47 years) had their heart rate and blood ...

Enterocins A and B and sakacin K at 200 and 2,000 activity units (AU)/cm2, nisin at 200 AU/cm2, 1.8% potassium lactate, and a combination of 200 AU/cm2 of nisin and 1.8% lactate were incorporated into interleavers, and their effectiveness against Listeria monocytogenes spiked in sliced, cooked ham was evaluated. Antimicrobial-packaged ...

The lactate threshold (LT) represents the onset of a metabolic acidosis during graded exercise testing (GXT). It is a valuable measurement in clinical exercise testing and correlates well with endurance performance. Our purpose was to compare three LT detection methods, namely, Inspection (work rate at onset of a systematic increase ...

Dynamic activities such as running, cycling, and swimming have been shown to effectively reduce lactate in the postexercise period. It is unknown whether core stabilization exercises performed following an intense bout would exhibit a similar effect. Therefore, this study was designed to assess the extent of the lactate response with ...

AIM: Physical activity and metformin are often used concomitantly in the treatment of diabetes, even though little is known about possible interactions between these treatment modalities. This study was designed to examine the acute effect of metformin on oxygen consumption and lactate concentration during exercise. METHODS: Eleven healthy, active men ...

Thesis (M.Sc.)--Chulalongkorn University, 2000

Intense exercise decreases the cerebral metabolic ratio of O(2) to carbohydrates (glucose + (1/2) lactate) and the cerebral lactate uptake depends on its arterial concentration, but whether these variables are influenced by O(2) availability is not known. In six males, maximal ergometer rowing increased the arterial lactate to 21.4 +/- ...

Peak oxygen uptake (VO2peak) is frequently difficult to assess in overweight individuals; therefore, submaximal measures that predict VO2peak are proposed as substitutes. Oxygen uptake efficiency slope (OUES) has been suggested as a submaximal measurement of cardiorespiratory fitness that is independent of exercise intensity. There are few data examining its value ...

Blood lactate markers are used as summary measures of the underlying model of an athlete's blood lactate response to increasing work rate. Exercise physiologists use these endurance markers, typically corresponding to a work rate in the region of high curvature in the lactate curve, to predict and compare endurance ability. ...

OBJECTIVE: The etiology of lung injury following cardiopulmonary bypass (CPB) is multifactorial. Our study focused on quantifying the lactate release from the lungs precipitated by extracorporeal circulation at different time points after the insult. This was complemented by an evaluation of the gas exchange at the level of the alveolar-capillary ...

The lactate minimum test (LACmin) has been considered an important indicator of endurance exercise capacity and a single session protocol can predict the maximal steady state lactate (MLSS). The objective of this study was to determine the best swimming protocol to induce hyperlactatemia in order to assure the LACmin in ...

INTRODUCTION: Historically, exercise performance outcomes may be predicted with anthropometric variables such as body mass. To assess body mass and resistance exercise (REX) performance variable correlations to blood lactate values, subjects performed five different workouts on two devices that do not employ gravitational resistance. One device uses flywheels to impose ...

In addition to having health-promoting effects, exercise is considered to induce oxidative stress. To clarify whether increased oxygen consumption during exercise induces oxidative stress, we investigated the effects of aerobic exercise and anaerobic exercise on a series of oxidative damage markers. One group of subjects performed aerobic exercise and another ...

The exponential rise in blood lactate with exercise intensity may be influenced by hepatic lactate uptake. We compared muscle-derived lactate to the hepatic elimination during 2 h prolonged cycling (62 +/- 4% of maximal O(2) uptake, (.)Vo(2max)) followed by incremental exercise in seven healthy men. Hepatic blood flow was assessed ...

Restricted Item. Print thesis available in the University of Auckland Library or available through Inter-Library Loan. This thesis addresses aspects of the physiology, behaviour and anatomy of fishes in order to test the hypotheses that (i) visual performance is influenced by metabolic stress and the development of an oxygen concentrating ...

Blood lactate concentration ([La(-)](b)) is one of the most often measured parameters during clinical exercise testing as well as during performance testing of athletes. While an elevated [La(-)](b) may be indicative of ischemia or hypoxemia, it may also be a "normal" physiological response to exertion. In response to "all-out" maximal ...

The aim of this study was to analyze the effects of exercise mode on the validity of onset of blood lactate accumulation (OBLA-3.5-mM fixed blood lactate concentration) to predict the work-rate at maximal lactate steady state (MLSS(work-rate)). Eleven recreationally active males (21.3+/-2.9 years, 72.8+/-6.7kg, 1.78+/-0.1m) performed randomly incremental tests to ...

Using a mixed-method approach, the aim of this study was to explore affective responses to exercise at intensities below-lactate threshold (LT), at-LT, and above-LT to test the proposals of the dual-mode model. These intensities were also contrasted with a self-selected intensity. Further, the factors that influenced the generation of those ...

BACKGROUND: Ginseng has been one of the most popular herbs said to improve human exercise performance. Unclear and anecdotal information is known about the effect of ginseng on lactate threshold and aerobic performance in humans. OBJECTIVE: The purpose of the present study was to investigate the effect of ginseng supplementation ...

The lactate threshold (LT) is commonly reported as not different between sexes, yet lower blood lactate concentrations have been reported in women during submaximal exercise. The purpose of the present study was to measure the changes in plasma lactate concentration [La(-1)] in men and women during incremental cycle ergometer exercise ...

We characterized carbohydrate metabolism following activity in the American bullfrog, Rana catesbeiana, and compared whole body metabolic profiles between two seasons. Forty-eight adult male Rana catesbeiana were chronically cannulated and injected with [U-(14)C]L-lactic acid sodium salt in either summer (June) or winter (January) after acclimation for 2 weeks at 15 ...

A novel method based on interleaved localized 31P- and 1H MRS is presented, by which lactate accumulation and the accompanying changes in high energy phosphates in human skeletal muscle can be monitored simultaneously during exercise and recovery. Lactate is quantified using a localized double quantum filter suppressing the abundant lipid ...

Lactobacillus plantarum produces peptidoglycan precursors ending in D-lactate instead of D-alanine, making the bacterium intrinsically resistant to vancomycin. The ligase Ddl of L. plantarum plays a central role in this specificity by synthesizing D-alanyl-D-lactate depsipeptides that are added to the precursor peptide chain by the enzyme MurF. Here we show ...

The glutamate-glutamine shuttle requires a flux of fixed N from neurons to astrocytes. The suggestion that some or all of this N is ammonium has received support from reports that ammonium (as NH(4)(+)) rapidly enters astrocytes. Ammonium might also help control astrocyte energy metabolism by increasing lactate production. If ammonium ...

Gastric exercise tonometry is a functional diagnostic test in chronic gastrointestinal ischemia. As maximal exercise can cause false-positive tests, exercise buildup should be controlled to remain submaximal. We evaluated three parameters for monitoring and adjusting exercise levels (heart rate [HR], respiratory quotient [RQ], and serial lactate measurements) in 178 tests ...

BACKGROUND: Although the blood lactate-to-pyruvate (L:P) molar ratio is used to distinguish between pyruvate dehydrogenase deficiency (PDH-D) and other causes of congenital lactic acidosis (CLA), its diagnostic accuracy for differentiating between these 2 types of CLA has not been evaluated formally. METHODS: We conducted a retrospective study of all patients ...

An amperometric l-lactate biosensor was fabricated by confining lactate oxidase in a Prussian Blue-modified electrode with a Nafion membrane. The detector was assembled in a flow injection apparatus and operated at -0.1 V. Conditions for optimal electrode response were determined by investigating the influence of the amount of immobilized enzyme, ...

The aim of this prospective study was to determine the feasibility of intestinal endoluminal microdialysis as a new method for clinical monitoring of the adequacy of splanchnic perfusion in the large bowel. A microdialysis catheter for continuous lactate, glycerol, glucose and pyruvate measurements attached to a tonometric catheter was placed ...

BACKGROUND: Normal response to different types of exercise needs to be established before performance, training level, or exercise intolerance can be assessed. OBJECTIVES: The aim of this research was to describe the hematologic and biochemical changes that dogs undergo during an agility competition. METHODS: Fifteen dogs were subjected to an ...

In most species the functional activity of the mammary gland during lactation follows a biphasic developmental pattern. This pattern starts with a rapid increase in milk output that occurs with secretory activation and continues with a more gradual increase until the point of peak lactation is reached. Following this gain-of-function ...

AIM: The aim of this work was to determine the ergogenic effects of a nucleotide supplement on the metabolic and immune responses to short term high intensity exercise in volunteer, trained, male subjects. METHODS: Thirty moderately trained male subjects were randomly divided into 3 equal sized groups, control (C), placebo ...

We examine the influence of the cytosolic and membrane-bound contents of carbonic anhydrase (CA; CAII, CAIII, CAIV, and CAXIV) and the muscle content of proteins involved in lactate and proton transport [monocarboxylate transporter (MCT) 1, MCT4, and Na(+)/H(+) exchanger 1 (NHE1)] on work capacity during supramaximal exercise. Eight healthy, sedentary ...

Bioelectrical Impedance Spectroscopy (BIS) is a noninvasive technology with potential application to study exercise physiology as body composition and estimation of maximal oxygen uptake. The aim of the study was to compare the power at lactate threshold (WLT) obtained using blood lactate concentration (BLC) with the power at lactate threshold ...

OBJECTIVE: Microdialysis can be used to monitor carbohydrate metabolism and lipolysis in adipose tissue. This method, however, does not discriminate between local metabolite production and delivery from other tissues. Our aim was to study glucose metabolism by direct delivery of 13C-labelled glucose into adipose tissue by microdialysis. MATERIAL AND METHODS: ...

Physiological variables, such as maximum work rate or maximal oxygen uptake (VO2max), together with other submaximal metabolic inflection points (e.g. the lactate threshold [LT], the onset of blood lactate accumulation and the pulmonary ventilation threshold [VT]), are regularly quantified by sports scientists during an incremental exercise test to exhaustion. These ...

The purpose of this investigation was to determine if the critical swimming velocity (CSV), defined as the theoretical maximal swimming velocity that could be maintained for a long period of time without exhaustion, corresponds to the exercise intensity at onset blood lactate accumulation (OBLA), and if it could be utilized ...

The aim of this study was to describe a double-bout exercise test for non-exhaustive aerobic capacity determination in swimming rats. Adult rats were submitted to 4 swimming tests at different intensities (4%, 6%, 7%, and 8% of body mass), with intervals of 48 h between them. Two exercise bouts of ...

Maximal blood lactate steady state concentration (MLSS) and anaerobic threshold (AT) have been shown to accurately predict long distance events performance and training loads, as well, in human athletes. Horse endurance races can take up to 160 km and, in practice, coaches use the 4 mM blood lactate concentration, a ...

The purpose of this study was to compare plasma markers of metabolic stress and other physiological parameters during prolonged endurance exercise of different intensity in trained subjects possessing a "high" or "low" lactate threshold (LT) expressed as a percentage (%) of peak power output (PPO). Fifteen trained male cyclists completed ...

Holstein steer calves (n = 25) were used to evaluate the effects of treadmill exercise (TME) on blood metabolite status and formation of dark-cutting beef. Calves were blocked by BW (156 +/- 33.2 kg) and assigned randomly within blocks to 1 of 5 TME treatments arranged in a 2 x ...

This study attempted to quantify the difference in heart rate and exercise stage at which blood lactate threshold (T(bla)) occurs using 3 different modes of exercise: running, double poling (DP) on roller skis, and skating (SK) on roller skis. Nine elite collegiate cross-country ski racers (4 men, 5 women) served ...