Aerobic Fitness Evaluation during Walking Tests Identifies the Maximal Lactate Steady State

Objective. The aim of this study was to verify the possibility of lactate minimum (LM) determination during a walking test and the validity of such LM protocol on predicting the maximal lactate steady-state (MLSS) intensity. Design. Eleven healthy subjects (24.2 ± 4.5 yr; 74.3 ± 7.7 kg; 176.9 ± 4.1 cm) performed LM tests on a treadmill, consisting of walking at 5.5 km · h−1 and with 20–22% of inclination until voluntary exhaustion to induce metabolic acidosis. After 7 minutes of recovery the participants performed an incremental test starting at 7% incline with increments of 2% at each 3 minutes until exhaustion. A polynomial modeling approach (LMp) and a visual inspection (LMv) were used to identify the LM as the exercise intensity associated to the lowest [bLac] during the test. Participants also underwent to 2–4 constant intensity tests of 30 minutes to determine the MLSS intensity. Results. There were no differences among LMv (12.6 ± 1.7%), LMp (13.1 ± 1.5%), and MLSS (13.6 ± 2.1%) and the Bland and Altman plots evidenced acceptable agreement between them. Conclusion. It was possible to identify the LM during walking tests with intensity imposed by treadmill inclination, and it seemed to be valid on identifying the exercise intensity associated to the MLSS

Relação entre velocidade crítica, limiar anaeróbio, parâmetros associados ao VO2max, capacidade anaeróbia e custo de O2 submáximo

The purposes of the study were to compare and correlate the running velocities associated with the maximal oxygen consumption (Vmax), anaerobic threshold (LL), ventilatory threshold (LV), critical velocity (CV), anaerobic work capacity (AWC) and oxygen cost during sub-maximal exercise (C). METHODS: Eight male physically active subjects (20.8±1.6 years; 74.3±14.9 kg), performed the following tests: 1) 500m and 3km time trial (Vm500 and Vm3km); 2) Incremental test on treadmill for of LL, LV, VO2max and Vmax identification; 3) sustained running at Vmax (Tmax) and identification of the time to VO2max and time at VO2max. The CV and AWC were obtained from linear regression (distance x time on 500m and 3km test). The C was determined as a ratio between sub-maximal running velocity and its VO2. RESULTS: A high correlation was verified for Vm3km and Vmax (r=0.83), Vm3km and VC (r=0.98), Vm500 and VC (r=0.90), Vm500 and Vm3km (r=0.92), and between Vm500 and Time to VO2max (r=0.69). No differences were observed between LL and LV (178.7±20.0 e 180.7±21.8m.min –1) (p>0.05). Also a high correlation between LL and Vmax¬ (r=0.91), CV (r=0.96), and Vm3km (r=0.96) were verified. The AWC was negatively correlated to running economy for those with higher aerobic capacity. CONCLUSION: The CV, AWC, Vm500 an Vm3km can be used for exercise evaluation and training prescription. Due the correlation with the C, the AWC may be an indicative of mechanical inefficiency.Os objetivos do estudo foram analisar as relações existentes entre a velocidade de corrida associada ao VO2max (Vmax), tempo para obtenção do VO2max na Vmax, tempo no VO2max, limiar de lactato (LL), limiar ventilatório (LV), velocidade crítica (VC), capacidade de trabalho anaeróbio (CTAn), desempenho em corrida de 500m e 3km e custo de O2 durante exercício submáximo (C). MÉTODOS: 8 homens fisicamente ativos (20,8±1,6 anos; 74,3±14,9kg) realizaram: 1) Corrida 3km e 500m máximos (Vm3km e Vm500). 2) Teste incremental em esteira para determinação do LL, LV, VO2max e Vmax. 3) Tempo de permanência na Vmax (Tmax), Tempo para atingir o VO2max e Tempo no VO2max. A VC e a CTAn foram obtidas (método linear) a partir dos testes de 3km e 500m. O C foi determinado dividindo-se a velocidade de corrida submáxima pelo respectivo VO2. RESULTADOS: Observou-se alta correlação entre Vm3km e Vmax (r=0,83), Vm3km e VC (r=0,98), Vm500 e VC (r=0,90) e entre Vm500 e Tempo no VO2max (r=0,69). Não foram verificadas diferenças entre LL e LV (178,7±20,0 e 180,7±21,8 m.min-1), sendo o LL altamente correlacionado com Vmax (r=0,91), VC (r=0,96) e Vm3km (r=0,96). Correlação positiva foi observada entre CTAn e C para indivíduos com maior aptidão aeróbia (r=0,79). CONCLUSÕES: As correlações apresentadas entre Vm500 e tempo no VO2max e entre Vm500 e VC indicam que exercícios de curta duração e alta intensidade são positivamente influenciados pela aptidão aeróbia. Devido a correlação significativa com o C, a CTAn se mostra como um possível indicador de ineficiência mecânica no exercício aeróbio

Corrida em esteira e exercícios de força: efeitos agudos da ordem de realização sobre a hipotensão pós-exercício

The study analyzed systolic (SBP) and diastolic (DBP) blood pressure after two exercise bouts of concurrent exercise performed in a different order [aerobic-strength (AS), and strength-aerobic (SA)]. Fifteen normotensive subjects were submitted to two exercise bouts performed in different days in the following order: AS and SA. SBP and DBP were measured before and at each 15 min over a 60 min period of post-exercise recovery. Post-exercise hypotension (PEH) was found in SBP at the 30th (-7.4 mmHg), 45th (-12.14 mmHg) and 60th min (-15.14 mmHg) after AS when compared to rest. On SA, PEH was only observed at the 60th min (-8.34 mmHg) of recovery. The analysis of differences for SBP and DBP between both sessions showed greater PEH at the 15th, 45th, and 60th min in SBP; and at the 45th min in DBP after AS when compared to SA. Thus, performing aerobic before strength exercise elicited a higher PEH in young adults.Este estudo analisou as respostas de pressão arterial sistólica (PAS) e pressão arterial diastólica (PAD) após duas sessões de exercício concorrente realizado em diferentes ordens [aeróbio-força (AF), e força-aeróbio (FA)]. Quinze indivíduos normotensos foram submetidos a duas sessões de exercício realizadas em dias distintos na seguinte sequência AF e FA. A PAS e PAD foram medidas antes e a cada 15 min durante 60 min de recuperação pós-exercício. Houve hipotensão pós-exercício (HPE) para PAS, aos 30 min (-7,4 mmHg), 45 min (-12,14 mmHg) e 60 min (-15,14 mmHg) de recuperação na sessão AF. Já na FA houve HPE apenas aos 60 min (-8,34 mmHg) de recuperação. A variação da PAS e PAD entre as sessões revelou HPE maior aos 15 min, 45 min e 60 min na PAS; e aos 45 min na PAD comparando-se AF a FA. A realização de exercício aeróbio antes do de força resultou em maior HPE para adultos jovens

<b> Prediction of maximal lactate steady state velocity based on performance in a 5km cycling test </b>

Stationary cycling tests were used to analyze the validity of methods for estimating the Maximal Lactate Steady State (MLSS) and the velocity and heart rate (HR) that are sustainable during a 40-km time trial. Methods: 11 cyclists (23.9±4.1 years; 178±6.8 cm tall; 68.8±5.4 kg) performed the following tests on a cyclosimulator, using their own bicycles: 1) Determination of the mean velocity and HR achieved during a 5-km (5kmVel and HR5km) and a 40-km time trial (40kmVel and HR40km). 2) 2-3 endurance tests to determine MLSSV with blood lactate ([lac]) measurements. The relationship between MLSSV and 5kmVel in data from Harnish et al. (2001) was also used to calculate predicted MLSSV (km•h-1): [MLSSVp = 0.8809 x 5kmVel + 1.6365]. The HR corresponding to MLSSV (MLSSHR) was estimated by taking 88% of HR5km (maximal- HR) (Swensen et al. 1999). Results: The 5kmVel, 40kmVel, MLSSV and MLSSVp were 50.07±2.03, 45.57±1.97, 45.64±2.0 and 45.77±1.77km•h-1 respectively. No differences were found between 40kmVel, MLSSV and MLSSVp. Neither did [lac] or HR corresponding to MLSSV/40kmVel exhibit differences 4.5±0.6/4.2±0.3mM and 175.1±3.0/176.8±3.1 bpm). The MLSSV was 90.9±0.5% of 5kmVel and MLSSHR was 93.6±0.5% of HR5km. Conclusion: The equation proposed is valid for estimating both MLSSV and 40kmVel on a stationary cyclosimulator.<p> <b> ABSTRACT</b> A validade de se estimar a velocidade e a frequência cardíaca (FC) correspondentes ao máximo estado estável de lactato sanguíneo (MEEL), bem como a velocidade e FC que poderiam ser mantidas durante uma prova simulada de 40-km foram estudados em ciclismo estacionário. Métodos: 11 ciclistas (23,9±4,1anos; 178±6,8cm altura; 68,8±5,4kg) realizaram os seguintes testes em ciclo-simulador, utilizando suas próprias bicicletas: 1) Determinação da velocidade média e a FC correspondentes aos testes de 5-km (5kmVel e FC5km) e 40-km (40kmVel e FC40km). 2) 2-3 testes de longa duração com dosagem de lactato sanguíneo [lac] para determinação do MEEL. O MEEL (km•h-1) foi estimado (MEELe) pela relação entre os resultados de MEEL e 5kmVel publicados por Harnish et al. (2001): [VSSMLp = 0,8809 x 5kmVel + 1,6365]. A FC correspondente ao MEEL (FCMEEL) foi estimada considerando 88% da FC5km (FCmáxima) (Swensen et al. 1999). Resultados: A 5kmVel, 40kmVel, MEEL and MEELe foram 50,07±2,03, 45,57±1,97, 45,64±2,0 and 45,77±1,77km•h-1 respectivamente. Não foram encontradas diferenças entre 40kmVel, MEEL e MEELe. A [lac] e a FC correspondentes ao MEEL/40kmVel (4,5±0,6/4,2±0,3mM e 75,1±3,0/176,8±3,1bpm) não foram diferentes entre si. O MEEL ocorreu a 90,9±0,5% de 5kmVel e a FCMEEL a 93,6±0,5% de FC5km. Conclusão: A equação proposta se mostrou válida para estimar tanto o MEEL quanto a velocidade em prova de 40km no ciclismo estacionário

<b>Post-Exercise Hypotension: Comparison Between Different Intensities Of Exercise On A Treadmill And A Cycle Ergometer</b>

To compare the hypotensive effects of exercise sessions performed on treadmill and cycle ergometer and toverify the infl uence of the intensity of such exercise sessions on post-exercise hypotension (PEH). Ten normotensive malesubjects (24.9 ± 3.9 years; 78.3 ± 9.2 kg; 176.9 ± 4.9 cm) performed 4 exercise sessions on different days: two incrementalexercise sessions on a cycle ergometer and a treadmill running until volitional exhaustion, and two continuous exercisesessions (20 min) on a cycle ergometer and a treadmill at intensities corresponding to 85% of maximal heart rate (max HR)reached during the incremental tests. Systolic (SBP) and diastolic blood pressure (DBP) were measured on resting, at theend of exercises and during the 90 minute post-exercise recovery period. After the incremental and continuous sessions onthe treadmill SBP presented a signifi cant reduction at the 45th and 90th minutes and DBP was reduced throughout the entirepost-exercise recovery period (P RESUMO O estudo teve como objetivo comparar os efeitos hipotensores de sessões de exercícios realizados em esteiraergométrica e cicloergômetro e verifi car a infl uência da intensidade dessas sessões sobre a hipotensão pós-exercício(HPE). Participaram do estudo 10 indivíduos normotensos do sexo masculino (24,9 ± 3,9 anos; 78,3 ± 9,2 kg; 176,9 ± 4,9cm) executaram 4 sessões de exercícios em dias distintos: dois testes incrementais em cicloergômetro e corrida em esteiraergométrica até a exaustão voluntária, e duas sessões de exercício contínuo (20 min) em cicloergômetro e esteira à 85%da freqüência cardíaca máxima (FC máx.) atingida nos testes incrementais. A pressão arterial sistólica (PAS) e diastólica(PAD) foram mensuradas em repouso pré-exercício, ao fi nal dos exercícios e durante 90 min de recuperação pós-exercício.Em relação aos valores de repouso pré-exercício, após as sessões de exercício incremental e contínuo em esteira aPAS se apresentou signifi cativamente reduzida (p < 0,05) aos 45 e 90 min, enquanto a PAD se apresentou diminuída (p< 0,05) durante todo o período de recuperação pós-exercício. Após as sessões de exercício incremental e contínuo emcicloergômetro, observou-se HPE de PAS aos 90 min de recuperação, enquanto que HPE de PAD foi observada aos 90min de recuperação apenas após sessão contínua submáxima (p < 0,05). Concluiu-se que o exercício realizado em esteirafoi mais efi caz que o exercício em cicloergômetro em induzir HPE. As intensidades de exercício empregadas nesse estudoparecem não exercer infl uência na HPE realizado em esteira e em cicloergômetro

Type 2 Diabetes Mellitus: Physiological and genetic aspects and the use of physical exercise for diabetes control.

Type 2 Diabetes mellitus (DM2) is a metabolic disease Type 2 Diabetes mellitus (DM2) is a metabolic disease characterized by hyperglycemia and cardiovascular dysfunctions that can be controlled with physical exercise, dietary control and pharmacological treatment. Recent research has demonstrated associations between DM2 and some genetic polymorphisms, especially alterations to the gene that codes for Angiotensin Converting Enzyme (ACE). The purpose of this study was to discuss the pathophysiology of DM2 and the use of physical exercise as a non-pharmacological method for controlling these patients’ glycemia and blood pressure. The relationship between DM2 and polymorphisms of the ACE gene was also covered. The literature search included textbooks in the healthcare field in addition to review articles and original articles found on the databases Pubmed, Scielo and Portal Capes. Keywords used were “blood glucose”, “type 2 diabetes”, “exercise”, “blood pressure” and “ACE gene polymorphism” and their translations in Portuguese. The main subject of this article is the practice of daily exercise, the types and intensities that have proven effective for glycemic and haemodinamic control and possible relationships with the ACE polymorphism, which are currently still tentative, since the evidence of associations can be strongly influenced by the population studied. The benefits of exercise are unquestionable and the recommended forms are discussed in this review. However the literature is still lacking studies that analyze the effects of physical exercise on diabetics and take into account the relationship with genetic aspects. This area is evidently an appropriate subject for further research