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

Hipotensão pós-exercício: possível relação com fatores étnicos e genéticos

A hipotensão pós-exercício (HPE) caracteriza-se pela redução dos valores pressóricos em relação ao pré-exercício, sendo intensamente estudada em diferentes populações a partir das diversas modalidades de exercício físico. Inúmeros mecanismos relacionam-se à HPE, tornando-a de origem multifatorial. No entanto, na última década, alguns estudos objetivaram investigar possíveis influências de fatores étnicos e genéticos sobre a HPE. Nesse sentido, o objetivo do presente estudo foi revisar os fatores ambientais e principalmente, os étnicos e genéticos relacionados à HPE. Os estudos utilizados nesta revisão de literatura foram obtidos a partir de um levantamento bibliográfico realizado nos seguintes bancos de dados disponíveis na internet: Medline,SciELO e Portal Capes. Com relação à etnia, verifica-se que os estudos apontam desfavorável tendência aos indivíduos negros em obter HPE quando comparados aos de etnia branca, embora ainda não seja possível afirmar de maneira categórica. Quanto aos estudos genéticos e HPE, ressalta-se a importância destes estudos, assim como a necessidade de que a seleção dos genes candidatos à investigação seja feita baseando-se no sistema fisiológico implicado na regulação da pressão arterial. Basicamente, os estudos publicados analisaram a relação entre HPE e mutações de genes que expressam proteínas envolvidas no sistema renina-angiotensina-aldosterona. Nesse sentido, parece que o maior decaimento da PA ocorre, principalmente, após exercícios aeróbios de baixa intensidade realizados por homens adultos e normotensos limítrofes ou hipertensos, sendo necessários mais estudos acerca do tema. _________________________________________________________________________________________ ABSTRACT: Post-exercise hypotension (PEH) is characterized by a decrease in blood pressure (BP) in relation to pre-exercise levels and has been intensively studied in different populations after different modes of exercise. Several mechanisms are associated with PEH, which makes it a multifactorial condition. However, over the last decade, some studies aimed to investigate the possible influence of ethnic and genetic factors on PEH. Thus, the purpose of this study was to review the environmental and, mainly, ethnic and genetic factors related to PEH. The studies used herein were obtained from a review of the following online databases: MEDLINE, SciELO and, Portal Capes. In relation to ethnicity, studies appear to indicate an unfavorable trend toward development of PEH in blacks as compared to whites, although this cannot be stated categorically. As for genetic studies and PEH, we stress the importance of these studies and highlight the need for selecting candidate genes for research on the basis of the physiological system implicated in BP regulation. Published studies have basically examined the relationship between PEH and mutations in genes that express proteins involved in the renin-angiotensin-aldosterone system. In this genetic sense, it seems that the greatest decline in PA occurs mainly after low-intensity aerobic exercise performed by normotensive or borderline hypertensive adult men. Further studies on the subject are required

Resposta da razão testosterona/cortisol durante o treinamento de corredores velocistas e fundistas

A razão entre as concentrações dos hormônios Testosterona e Cortisol (T/C) tem sido utilizada para um melhor controle das cargas de treinamento. Os objetivos deste estudo foram investigar e comparar o comportamento da razão T/C e sua relação com o volume e intensidade realizados durante um período de treinamento de atletas velocistas e fundistas. Corredores velocistas (CV-25,8 ± 3,5anos; 174 ± 7,2 cm, 71,1 ± 3,7 kg; n = 6) e fundistas (CF-27,5 ± 8,7 anos, 174 ± 3,8 cm, 67,7 ± 5,8 kg; n = 6), executaram o seguinte teste padronizado de corrida pré e pós um mesociclo de treino: 1 x 500 m à máxima intensidade e 6 x 800 m progressivos. Sangue venoso (5 ml) foi coletado em repouso, após a corrida de 500 m e ao final de 6 x 800 m para determinação das concentrações de testosterona e cortisol (radioimunoensaio). Os fundistas realizaram um maior volume de treinamento, enquanto os velocistas realizaram treinamentos de menor volume, porém mais intensos e com maior participação anaeróbia. Não houve diferen- ça significante para os valores médios da razão T/C para ambos os grupos após o período de treinamento. No entanto, quando se observa o comportamento individual da razão T/C, nota-se uma resposta adaptativa adequada para alguns indivíduos e inadequadas para outros, sendo que a maior incidência de queda da razão T/C foi observada entre os CF. Conclui-se que a utilização da razão T/C para o controle das cargas de treinamento deve ser feita individualmente, e que aparentemente esta variável sofre uma maior influência do volume do treinamento do que da intensidade do mesmo.Response of the testosterone to cortisol ratio during training for sprinters and endurance runners The testosterone/cortisol ratio (T/C) has been suggested for exercise evaluation and training control (BANFI et al., 1993). The purpose of this study was to investigate the plasma testosterone (T) and cortisol (C) responses during a period of training preparation for sprinters and endurance runners. Six endurance runners (ER; 27.5 ± 8.7 years; 174 ± 3.8 cm, 67.7 ± 5.8 kg; n = 6) and six sprinters (SR; 25.8 ± 3.5 years; 174 ± 7.2 cm, 71.1 ± 3.7 kg; n = 6 ) that were participating on the 1st phase (P1) of their training period volunteered to this study. The participants performed the following running test, before (pre) and after (post) accomplishing the 2nd phase (P2) of training: Standardized test of exercise- After an all-out 500 m for lactic acidosis induction, the subjects ran 6 x 800 m at intensities between 84 and 99% of their best 3 km performance. The levels of T and C were measured (radioimmunoassay) at rest and immediately after the 500 m all-out and at the end of the 6 x 800 m bouts. The ER performed a higher total training volume (TTV) with predominance of moderate to heavy intensity. The SR performed low TTV with a higher % of their TTV at higher intensities (heavy to severe intensities), mainly during P2. No differences were observed for the mean T/C results for both groups after P2. However, when the data are analyzed on individual basis, an adaptative response was observed for some athletes but not for others. A higher incidence of T/C decrease was observed for ER. It was concluded that the T/C ratio analyzes for training control must be done on individual basis. Also, volume instead of intensity of training seems to have higher influence on T/C ratio