Vilmar Baldissera

Blood glucose responses in humans mirror lactate responses for individual anaerobic threshold and for lactate minimum in track tests

Abstract The equilibrium point between blood lactate production and removal (La−min) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La−]b, catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc]b, this study investigated the [Glc] and [La−]b responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum (Glcmin) in addition to IAT and La−min in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v3km); IAT and IGT – 8 × 800 m runs at velocities between 84% and 102% of v3km; La−min and Glcmin– after lactic acidosis induced by a 500-m sprint, the subjects ran 6 × 800 m at intensities between 87% and 97% of v3km; endurance test (ET) – 30 min at the velocity of IAT. Capillary blood (25 μl) was collected for [La−]b and [Glc]b measurements. The IAT and IGT were determined by [La−]b and [Glc]b kinetics during the second test. The La−min and Glcmin were determined considering the lowest [La−] and [Glc]b during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21) m. · min−1; r = 0.096; P < 0.001] and between La−min [285 (SD 21)] and Glcmin [287 (SD 20) m. · min−1r = 0.77; P < 0.05]. During ET, the [La−]b reached 5.0  (SD 1.1) and 5.3 (SD 1.0) mmol · l−1 at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glcmin as well as by IAT and La−min.

Effects of resistance training on resistin, leptin, cytokines, and muscle force in elderly post-menopausal women

Abstract It may be that resistance exercise can be used to prevent the degenerative processes and inflammation associated with ageing. Thus, the aim of the present study was to evaluate the effects of resistance training on cytokines, leptin, resistin, and muscle strength in post-menopausal women. Thirty-five sedentary women (mean age 63.18 years, s = 4.8; height 1.64 m, s = 0.07; body mass 57.84 kg, s = 7.70) were recruited. The 16 weeks of periodized resistance training consisted of two weekly sessions of three sets of 6–14 repetition maximum. Maximal strength was tested in bench press, 45° leg press, and arm curl. Plasma tumour necrosis factor-α, interleukin-6, interleukin-15, leptin, and resistin were determined by enzyme-linked immunosorbent assay. Maximal strength on all measures was increased after 16 weeks. There were minor or no modifications in tumour necrosis factor-α and interleukin-15. Interleukin-6 was decreased 48 h after compared with baseline and declined after 16 weeks. Leptin decreased 24 h after compared with baseline and was reduced at baseline and 48 h after compared with pre-training. There was a decrease in resistin after 24 and 48 h compared with baseline and a decline in baseline and immediately after levels compared with pre-training. A possible explanation of the results of the present study is a lower production of pro-inflammatory cytokines by the innate immune system. Periodized resistance training seems to be an important intervention to reduce systemic inflammation in this population.

Hypotensive effects of exercise performed around anaerobic threshold in type 2 diabetic patients

AIM To verify the occurrence of post-exercise hypotension (PEH) in type 2 diabetics (DM(2)) and the effects of exercise intensity on post-exercise blood pressure (BP). METHODS Eleven men and women with DM(2) (58.5+/-10.2 years; 160+/-0.1cm; 80.6+/-13.5kg; 31.2+/-3.8kg/m(2), 19+/-3.2mLkgmin(-1) of VO(2max), 155.0+/-39.2mgdL(-1) of fasting blood glucose and 126+/-10/75+/-7mmHg of resting BP) performed an incremental test (IT) for cardiovascular evaluation and anaerobic threshold (AT) determination. Then, participants randomly underwent 2 exercise sessions (90% and 110% AT) and a control session (CON). In all sessions, BP was measured at resting, during 20min of exercise/control and at each 15min through 120min of post-exercise recovery (R15-R120). RESULTS The mean results of systolic BP (SBP)/diastolic BP (DBP) over the 120min of recovery were 125+/-16/76+/-7mmHg, 122+/-13/75+/-6mmHg and 129+/-16/78+/-7mmHg, respectively for 90%, 110% and CON. Significant reductions of SBP occurred after 90% (R15-R45) and 110% (R15-R90), while only after 110% there were reductions of DBP (R15, R45) and MAP (R15, R45, R75, R90, R105). CONCLUSIONS Both exercise intensities evoked reductions in SBP while DBP and MAP were reduced only after 110%. Despite the higher intensity exercise to be more effective in promoting BP reductions, we suggest caution while prescribing exercise for DM(2).

Heart-rate variability and blood-lactate threshold interaction during progressive resistance exercise in healthy older men.

Simões, RP, Mendes, RG, Castello, V, Machado, HG, Almeida, LB, Baldissera, V, Catai, AM, Arena, R, and Borghi-Silva, A. Heart-rate variability and blood-lactate threshold interaction during progressive resistance exercise in healthy older men. J Strength Cond Res 24(5): 1313-1320, 2010-The objective of this study was to (a) evaluate the impact of the leg press, at variable percentages of 1 repetition maximum (1RM), on heart rate variability (HRV) and blood lactate and (b) determine the relationship between HRV with blood lactate in a healthy elderly cohort. Ten healthy men (64 ± 4 years) participated in a progressive leg-press protocol to maximal exertion. Initially, 1RM for the leg press was determined for all subjects. The protocol then began at 10% of 1RM, with subsequent increases of 10% until 30% of 1RM, followed by incremental adjustments of 5% until exhaustion. The measurement of instantaneous R-R interval variability from Poincare plots (SD1 and SD2) and time domain indexes (RMSSD and RMSM), blood pressure, and blood lactate were obtained at rest and all leg-press loads. Significant alterations of HRV and blood lactate were observed from 30% of 1RM leg press (p < 0.05). Additionally, significant correlations were found between the lactate threshold (LT) and the RMSSD threshold (r = 0.78; p < 0.01), and between the LT and SD1 threshold (r = 0.81, p < 0.01). We conclude that metabolic and cardiovascular alterations are apparent during relatively low resistance exercise (RE) loads in apparently healthy subjects. In addition, HRV indexes were associated with blood-lactate levels during RE. The practical applications is the possibility of using HRV as a noninvasive measure obtained at a relatively low cost may be used to identify neural and metabolic alterations during RE in older subjects.

L-carnitine as an ergogenic aid for patients with chronic obstructive pulmonary disease submitted to whole-body and respiratory muscle training programs

The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease (COPD) patients. Sixteen COPD patients (66 +/- 7 years) were randomly assigned to L-carnitine (CG) or placebo group (PG) that received either L-carnitine or saline solution (2 g/day, orally) for 6 weeks (forced expiratory volume on first second was 38 +/- 16 and 36 +/- 12%, respectively). Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions, with 3 sets of 10 loaded inspirations (40%) at maximal inspiratory pressure. Nutritional status, exercise tolerance on a treadmill and six-minute walking test, blood lactate, heart rate, blood pressure, and respiratory muscle strength were determined as baseline and on day 42. Maximal capacity in the incremental exercise test was significantly improved in both groups (P < 0.05). Blood lactate, blood pressure, oxygen saturation, and heart rate at identical exercise levels were lower in CG after training (P < 0.05). Inspiratory muscle strength and walking test tolerance were significantly improved in both groups, but the gains of CG were significantly higher than those of PG (40 +/- 14 vs 14 +/- 5 cmH2O, and 87 +/- 30 vs 34 +/- 29 m, respectively; P < 0.05). Blood lactate concentration was significantly lower in CG than in PG (1.6 +/- 0.7 vs 2.3 +/- 0.7 mM, P < 0.05). The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients, as well as reduce lactate production.

THE IMPACT OF NONINVASIVE VENTILATION DURING THE PHYSICAL TRAINING IN PATIENTS WITH MODERATE-TO-SEVERE CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)

OBJECTIVE To evaluate the influence of physical training with or without noninvasive ventilation at 2 levels of pressure in the airways (BiPAP) in patients with chronic obstructive pulmonary disease. METHODS Eighteen patients with FEV(1) = 34 +/- 8% of predicted values, mean age of 68 +/- 9 years were randomly distributed into 2 groups, one group performing physical training on a treadmill and the other group performing physical training associated with BiPAP (physical training+B), for 30 minutes, 3 times a week for 12 weeks. The training velocity was based on a test of cardiopulmonary force performed pre- and postintervention, which registered the values for heart rate, systolic blood pressure, diastolic blood pressure, peripheral oxygen saturation, blood lactate, sensation of dyspnea, respiratory muscle strength, and analysis of gases expired such as oxygen consumption and the production of carbon dioxide. RESULTS For both groups, there was a significant improvement in dyspnea and peripheral oxygen saturation at identical levels of physical exercise, in distance walked during the physical training, and in respiratory muscle strength (P < 0.05). Only the physical training+B group had a significant improvement in heart rate, systolic blood pressure, and oxygen consumption after training (P < 0.05). Significant reductions of blood lactate were observed at identical levels of exercise in physical training+B when compared to isolated physical training (from 1.3 +/- 0.7 mMol/L versus 2.5 +/- 0.9 mMol/L, (P < 0.05), respectively). CONCLUSION Physical training associated with BiPAP enhanced the oxidative muscular capacity and could be an adjunctive recourse for physical rehabilitation in patients with chronic obstructive pulmonary disease.

The measurement of lactate threshold in resistance exercise: a comparison of methods.

Resistance incremental tests (IT) make it possible to determine critical metabolic and cardiovascular changes, such as the lactate threshold (LT). Different methods are frequently used to improve the exactness of LT identification. The objective of the study was to identify LT by four different methods (visual inspection, log–log, algorithmic adjustment and QLac) during resistance exercise and to evaluate which methods present more precision. Twelve men performed a maximal IT on the leg press at relative intensities of 10%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80% and 90% of 1RM with 1‐min stages. During the 2‐min interval between stages, capillary blood was collected for blood lactate analysis. LT was detected using each of the four methods. The intensity of LT by visual inspection method was 26·9 (5·2)% of 1RM, adjustment algorithmic method was 27·8 (3·6)% of 1RM, log–log method was 23·3 (3·5)% of 1RM and QLac method was 31·6 (9·8)% of 1RM, with significant difference only between log–log and QLac methods. Bland and Altman analysis shows better concordance for visual inspection versus adjustment algorithmic methods. The visual inspection, algorithmic and log–log methods detected the LT at the same intensity. The mathematical models, specially the algorithmic method, provide more precision.

Effects of resistance training on matrix metalloproteinase‐2 activity and biomechanical and physical properties of bone in ovariectomized and intact rats

The purpose of this study was to investigate the influence of resistance training on the activity of matrix metalloproteinase (MMP)‐2 and bone biomechanical properties in ovariectomized and intact rats. Forty‐eight female rats were divided into two distinct groups, ovariectomized (OVX) and intact (Int), which were subdivided into three similar subgroups: sedentary, acute exercise and chronic exercise. Rats performed a resistance training for 12 weeks in which animals climbed a vertical ladder of 1.1 m with weights attached to their tails. Sessions were performed with an interval of 3, 4–9 and 8–12 days scaled dynamic movements of climbing. Biomechanical and physical analyses were performed using a universal testing machine, and MMP‐2 activity analysis by zymography. Bone density (BD), mineral density (MD), maximum load and fracture load was reduced in sedentary and acute exercise OVX groups compared with the sedentary intact group (P<0.05); in contrast, chronically trained groups (OVX and Int) showed a significant increase in BD, MD and fracture load compared with all the other groups. MMP‐2 activity in chronically trained groups also showed a significant increase, while the sedentary OVX group showed a decrease in MMP‐2 activity compared with the intact sedentary group (P<0.05). Our results suggest that the resistance training proposed in our work was efficient in reverting the deleterious effects of ovariectomy on bone tissue, and also produced modeling effects in intact rats. On the other hand, ovariectomy reduced the activity of MMP‐2 and produced deleterious effects on bone tissue, mimicking menopause intrinsically.

Comparação entre a utilização de saliva e sangue para determinação do lactato mínimo em cicloergômetro e ergômetro de braço em mesa-tenistas

The aim of this study was to verify if it is possible to determine the lactate minimum test (LMT) by saliva sodium (Na + ), potassium (K + ) and lactate (LAC) concentrations in arm ergometer and cycle ergometers. Eight male international-level table tennis players participated in this study. To induce increases of lactate concentration in both ergometers, 30 seconds maximal tests were used with maximal force application in constant 102 rpm in isokinetic arm ergometer (Cybex UBE 2432), and loads of 7.5% of body weight (Kp) in cycle ergometer (mechanical Monark). After the anaerobic stimulus in arm ergometer, the incremental test was applied at constant 60 rpm, started at 49 watts and increment loads of 16 watts each three minutes. The LMT intensity was determined with the analysis of the blood lactate (LACmin arm ) and the saliva concentrations of sodium (Na + minarm-saliva) and potassium (K + minarm-saliva). For the cycle ergometer, the incremental test started with an intensity of 85 watts and increments of 17 watts at constant speed of 70 rpm. The stages were also of three minutes. The LACmin was determined using blood and saliva samples (LACmincycle; Na + mincyclesaliva , K +min cycle-saliva and LACmin cycle-saliva , respectively). In both ergometers, the intensity obtained in lactate minimum test was correspondent to zero derived polynomial adjustments by metabolite concentrations versus exercise intensities. The statistical analysis included one way ANOVA test, paired t-test and Pearson’s correlations. For all tests applications, the significance level was prefixed at 5%. The several LACmin determinations using blood and saliva samples did not show significant differences in arm and cycle ergometers (LACminarm 91.71 ± 12.43; Na + minarm-saliva 71.99 ± 23.42;O objetivo do estudo foi verificar a possibilidade de determinar o teste de lactato minimo (TLM) com concentracoes de sodio (Na+), potassio (K+) e lactato (LAC) na saliva em ergometro de braco e cicloergometro. Foram participantes deste estudo oito mesa-tenistas de nivel internacional. Como estimulo anaerobio no TLM em ambos os ergometros foram utilizados testes maximos de 30 segundos. No ergometro de braco isocinetico (Cybex Ube 2432) foi aplicada a forca maxima com rotacao fixa em 102rpm e no cicloergometro, aplicada a carga de 7,5% do peso corporal (Kp). Apos o estimulo anaerobio no ergometro de braco, foi iniciado um teste incremental com rotacoes na manivela constante a 60rpm, iniciado a 49 watts com aumento de 16 watts a cada estagio de tres minutos de exercicio. A intensidade correspondente ao TLM foi determinado com amostras de sangue e saliva (LACminbraco; Na+minbraco-saliva e K+minbraco-saliva, respectivamente). Para o cicloergometro, a carga inicial foi de 85 watts e aumento de 17 watts com rotacao do pedal constante a 70rpm. Cada estagio de exercicio tambem teve a duracao de tres minutos. O LACmin foi determinado utilizando amostras de sangue e saliva (LACminciclo; Na+minciclo-saliva, K+minciclo-saliva e LACminciclo-saliva, respectivamente). Em ambos os ergometros, as intensidades obtidas no TLM foram correspondentes a derivada zero do ajuste polinomial entre metabolito versus intensidade. Foram utilizados, como procedimentos estatisticos, o teste ANOVA One Way, teste t de Student pareado e teste de correlacao de Pearson com niveis de significância de 5%. Os LACmin determinados com amostras de sangue e de saliva, tanto para o ergometro de braco (LACminbraco 91,71 ± 12,43; Na+minbraco-saliva 71,99 ± 23,42; K+minbraco-saliva 79,67 ± 17,72), quanto para cicloergometro (LACminciclo 157,68 ± 13,48; LACminciclo-saliva 135,49 ± 33,2; Na+minciclo-saliva 121,81 ± 51,31; K+minciclo-saliva 135,49 ± 33,21), nao foram diferentes significativamente. Contudo, essas intensidades nao apresentaram correlacoes significativas. Pode-se entao concluir que a utilizacao de metabolitos na saliva para determinacao do TLM nao parece ser possivel para esse protocolo quando os ergometros utilizados sao o ergometro de braco isocinetico e o cicloergometro.

Concentrações sangüíneas de lactato em eqüinos durante a prova de fundo do concurso completo de equitação

Blood samples were collected from thirteen horses competing in the resistance phase of an advanced 3-day-event. Blood lactate was determined in the morning before competition, before and immediately after phases B and D, and 10 minutes after phase D. Significant increase in blood lactate was observed only after phase D, showing that animals were submitted to a great physical effort with development of metabolic acidosis due to lactate accumulation. There was significant decrease in blood lactate levels 10 minutes after cross country except horse 12, the only animal to finish phase D inside the given time, but showed clinical signs of exhaustion.