Residual effects of mental fatigue on subjective fatigue, reaction time and cardiac responses / Efectos residuales de la fatiga mental en la fatiga subjetiva, tiempo de reacción y respuestas cardíacas / Efeitos residuais da fadiga mental na fadiga subjetiva, tempo de reação e respostas cardíacas

This study investigated the residual effects of mental fatigue induced by the 30-minute incongruent Stroop Color Word task on subjectively perceived fatigue, reaction time, and heart rate variability (HRV) in 20 adult volunteers (10 men; 10 women). Dependent variables were assessed before, immediately after, and at 15, 30, 45, and 60 minutes after two conditions: (a) a 30-minute incongruent Stroop Color Word task (mental fatigue condition); or (b) a 30-minute control condition. At pre-testing, there were no significant differences between experimental conditions for any variable. However, there was a residual effect of mental fatigue on psychological responses for up to ~15 minutes after the experimental manipulation (p < 0.01). For the reaction time task, significant differences were observed only immediately after the mental fatigue, compared to the control condition (p < 0.0001). There were no significant differences between experimental conditions for any parameters of HRV at any testing period. In addition, there were no significant gender related differences at any period or in either condition for any variable. The data suggest that mental fatigue can alter psychological responses for up to ~15 min after its induction, and mental fatigue may impair cognitive reaction time performance without changing autonomic cardiac responses

Este estudio investigó los efectos residuales de la fatiga mental inducidos por 30 minutos Test de Stroop con palabra con color incongruente sobre la fatiga percibida subjetivamente, el tiempo de reacción y la variabilidad de la frecuencia cardíaca (HRV) en 20 voluntarios adultos (10 hombres, 10 mujeres). Las variables dependientes se evaluaron antes, inmediatamente después y a los 15, 30, 45 y 60 minutos después de dos condiciones: (a) Test de Stroop con palabra con color incongruente de 30 minutos (condición de fatiga mental); o (b) condición de control de 30 minutos. En la pre condiciones, no hubo diferencias significativas entre las condiciones experimentales para ninguna variable. Sin embargo, hubo un efecto residual de la fatiga mental en las respuestas psicológicas durante hasta ~ 15 minutos después de la manipulación experimental (p < 0,01). Para la tarea de tiempo de reacción, se observaron diferencias significativas solo inmediatamente después de la fatiga mental, en comparación con la condición de control (p < 0,0001). No hubo diferencias significativas entre las condiciones experimentales para ningún parámetro de HRV en ningún período. Además, no hubo diferencias significativas relacionadas con el género en ningún período ni en ninguna de las condiciones para ninguna variable. Los datos sugieren que la fatiga mental puede alterar las respuestas psicológicas hasta ~ 15 min después de su inducción, y la fatiga mental puede afectar el rendimiento del tiempo de reacción cognitiva sin cambiar las respuestas cardíacas autónomas

Este estudo investigou os efeitos residuais da fadiga mental induzida por 30 minutos do teste de Stroop com a palavra de cor incongruente na fadiga percebida de maneira subjetiva, tempo de reação e variabilidade da frequência cardíaca (VFC) em 20 voluntários adultos (10 homens; 10 mulheres). As variáveis dependentes foram avaliadas antes, imediatamente após e aos 15, 30, 45 e 60 minutos após duas condições: (a) teste de Stroop com a palavra de cor incongruente de 30 minutos (condição fadiga mental); ou (b) uma condição controle de 30 minutos. No pré-teste, não houve diferenças significativas entre as condições experimentais para qualquer variável. No entanto, houve um efeito residual da fadiga mental nas respostas psicológicas por até ~ 15 minutos após a manipulação experimental (p <0,01). Para o teste de tempo de reação, foram observadas diferenças significativas apenas imediatamente após a fadiga mental, em comparação com a condição controle (p <0,0001). Não houve diferenças significativas entre as condições experimentais para quaisquer parâmetros da VFC em qualquer período. Além disso, não houve diferenças significativas relacionadas ao gênero em qualquer período ou em qualquer condição para qualquer variável. Os dados sugerem que a fadiga mental pode alterar as respostas psicológicas por até 15 minutos após sua indução, e a fadiga mental pode prejudicar o desempenho cognitivo pela piora tempo de reação sem alterar as respostas autonômicas cardíacas

Effects of walk training with self-selected intensity on biochemical markers and anthropometric variables in women with obesity.

To evaluate the effects of 12-weeks of walk training with self-selected intensity on lipid profile and anthropometric variables in women with obesity. Forty-eight women volunteers with obesity were randomly assigned into two training groups: self-selected walking group (SSWG; n=25) and control group (CG; n=23). There was improvement in biochemical markers only in the SSWG post-intervention (p<0.05), however no changes were verified in anthropometric variables (p>0.05). This study demonstrates that walking at self-selected intensity improved the lipid profile in women with obesity.

Effect of walk training combined with blood flow restriction on resting heart rate variability and resting blood pressure in middle-aged men

Aim: To investigate the effects of low-intensity walk training with and without blood flow restriction (BRF) on resting heart rate variability (HRV) and blood pressure (BP) in middle-aged men. Methods: Twenty-one men were randomly assigned into the walk training group with (BRF-W; n = 11) and without (NOR-W; n = 10) BFR. The resting HRV and blood pressure were assessed pre- and post-6 weeks of the intervention [3 times/week, 5 sets of 3-min walking (6 km.h-1) with 1-min of rest, totalizing 18 sessions of training]. The BFR-W group received the occlusive stimulus before of training sessions though of a standard sphygmomanometer and performed the training sessions with the vascular occlusion (80-100 mmHg) in both the legs. Results: Only BRF-W group improved HRV on time domain indices (SDNN and RMSSD; p < 0.05) after training but it was not found differences on frequency domain indices. In addition, systolic blood pressure (SBP) improved after training (PRE: 128.5 ± 5.9 vs POST: 119.1 ± 8.6 mmHg; Cohen's d = -1.30; p < 0.01) only in BFR-W group. There was not a significant difference on diastolic blood pressure (DBP) after training, however, effect size was moderate for BFR-W (Cohen's d = -0.56; p > 0.05). Conclusion: Our results showed that walking training with blood flow restriction can improve health cardiovascular parameters in middle-aged men.(AU)

Cardiac autonomic responses during and after a single session of aerobic exercise with and without blood flow restriction

Aim: To verify the on and off heart rate (HR) and HR variability (HRV) kinetics during a high-load aerobic exercise and a low-load aerobic exercise, with and without blood flow restriction (BFR). Methods: Fourteen healthy male subjects performed three randomly assigned experimental sessions: 1) 10 minutes walking at 40% of maximal aerobic speed (MAS) (40LL); 2) 10 minutes walking at 40% of MAS with BFR (40LL+BFR); and 3) 10 minutes running at 70% of MAS (70HL). The HR and HRV measurements were taken at rest, during exercise and the recovery period after constant load sessions. Results: The HR on- and off- kinetics, and HRV on-kinetics were faster in 40LL than in 40LL +BFR and 70HL (p < 0.05). The time constant (τon) of HR on-kinetics was faster in 40LL+BFR than in 70HL (23.4 ± 9.5 s vs 42 ± 9.5 s, respectively, p < 0.01), and was accompanied by faster HRV on-kinetics (12.4 ± 9.6 s vs 20.3 ± 13.7 s, respectively, p < 0.01). Although HR off-kinetics was not different between 40LL+BFR and 70HL, the recovery of time and frequency HRV indices were delayed in 70HL when compared to 40LL and 40LL+BFR (p < 0.05). Conclusions: These findings indicate that 40LL promoted faster cardiac adjustments compared to 40LL+BFR and 70HL sessions. Additionally, 40LL+BFR promoted faster cardiac adjustment and better HRV recovery compared to the 70HL session. (AU)

Cardiac autonomic responses and number of repetitions maximum after LED irradiation in the ipsilateral and contralateral lower limb.

The aim of this study was to verify the maximum number of repetitions, fatigue index, blood lactate concentration ([Lac]), and cardiac autonomic responses after LED irradiation (LEDI) in the ipsilateral and contralateral limb. Twelve male subjects (22.0 ± 3.86 years; weight 82.94 ± 12.58 kg; height 1.77 ± 0.05 m), physically active, took part in this study. The subjects underwent a one repetition maximum (1RM) test and performed four randomly experimental sessions in the horizontal leg press exercise, which consisted in four sets of maximum repetitions at 80% of 1RM. The subjects performed two experimental sessions applying LED active or placebo on ipsilateral limb and two experimental sessions applying LED active or placebo on contralateral limb prior exercise and in the interval of sets on quadriceps and hamstrings muscles. A number of repetitions and fatigue index were verified. [Lac] and heart rate variability (HRV) were collected during post-exercise recovery and analyzed. It was observed that active LEDI promoted an increase in maximal number of repetitions (LEDI = 44.4 ± 9.0 vs placebo = 39.9 ± 11.4; p < 0.05) and decreases the fatigue index (LEDI = 34.3 ± 21.8% vs placebo = 50.0 ± 26.6%; p < 0.05) comparing to placebo situation, only in the ipsilateral application. There were no differences on [Lac] and in HRV parameters comparing LEDI vs placebo on post-exercise recovery in both applications (p > 0.05). The LEDI improves performance only in the ipsilateral application, but there were no differences on [Lac] and cardiac autonomic responses after exercise for both the applications.

Comparison between non-exhaustive critical velocity estimated by heart rate with exhaustive critical velocity and heart rate variability threshold / Comparación entre velocidad crítica no exhaustiva estimada por la frecuencia cardíaca con velocidad crítica exhaustiva y el umbral de la variabilidad de la frecuencia cardíaca

The aim of this study was to compare the critical velocity determined by a non-exhaustive test (CVNE) using heart rate (HR) as physiological variable with the exhaustive critical velocity (CV) and the heart rate variability threshold (HRVT). Twelve male subjects (20.1 ± 1.6 years; 73.4 ± 10.3 kg; 1.76 ± 0.06 m) physically active took part of this study and performed an incremental test to determination the peak velocity and HRVT, three constant-load exhaustive tests to CV estimates and three non-exhaustive tests with two bouts of three minutes to CVNE determination. The percentages used to CV estimates were of 97%, 111% and 130% of peak velocity from incremental test and to CVNE were used of 72%, 92% and 110% of peak velocity. The incremental test was also important to determine the HRVT. The difference between CVNE vs HRVT (2.61 ± 12.84 km.h-1 vs 7.92 ± 1.16 km.h-1) and the CVNE vs CV (2.61 ± 12.84 km.h-1 vs 12.20 ± 1.38 km.h-1; p > 0.05) was not statistically significative, but a significant difference was observed between the HRVT and CV (7.92 ± 1.16 km.h-1 vs 12.20 ± 1.38 km.h-1) (p < 0.01). The CVNE demonstrated low agreement and weak correlation with HRVT (bias ± limits of agreement = -5.31 ± 25.09 km.h-1; r = 0.08) and CV (bias ± limits of agreement = -9.59 ± 25.94 km.h-1; r = -0.23). Thus, the CVNE estimated by HR is not a valid parameter to evaluation of metabolic transition and to prescribe aerobic exercise

El objetivo de este estudio fue comparar a velocidad crítica determinada por un test no exhaustivo (CVNE) utilizando como variable fisiológica la frecuencia cardíaca (HR) con velocidad crítica exhaustiva (CV) y el umbral de la variabilidad de la frecuencia cardíaca (HRVT). Veinte sujetos hombres (20,1 ± 1,6 años; 73,4 ± 10,3 kg; 1,76 ± 0,06 m) físicamente activos participaron en el estudio y realizaron un test incremental para determinar la velocidad pico y HRVT, tres exhaustivos testes de carga constante para estimar a CV y tres testes no exhaustivos con dos episodios de tres minutos para determinar la CVNE. Los porcentajes utilizados para estimar a CV fueron 97%, 111% y 130% de la velocidad pico del test incremental y en CVNE fueron usados 72%, 92% y 110% de la velocidad pico. El test incremental también era importante para determinar la HRVT. La diferencia entre la CVNE vs HRVT (2,61 ± 12,84 km.h-1 vs 7,92 ± 1,16 km.h-1) y el CVNE vs CV (2,61 ± 12,84 km.h-1 vs 12,20 ± 1,38 km.h-1; p > 0,05) no fue estadísticamente significativa, pero él se observaron diferencias significativas entre el HRVT y la CV (7,92 ± 1,16 km.h-1 vs 12,20 ± 1,38 km.h-1) (p < 0,01). El CVNE demostró menor concordancia y correlación con HRVT (sesgo ± límites de acuerdo = -5,31 ± 25,09 km.h-1; r = 0,08) y CV (sesgo ± límites de acuerdo = -9,59 ± 25,94 km.h-1; r = -0,23). Por lo tanto, la CVNE estimado por HR no es un parámetro válido para la evaluación de la transición metabólica y prescribir ejercicio aeróbico

Comparative analysis between maximum oxygen uptake and anthropometric profile in soccer players and referees

The aim of this study was to analyze and compare the VO2max and anthropometric profile of referees and professional soccer players. The population was composed by professional soccer players and referees, credited by Paranaense Soccer Federation (FPF). The sample was composed by 10 referees from FPF panel and 24 players from a team that operate in highest level of Paranaense championship, all male. Leger test (comes and goes) was used for field measurement of VO2max. Anthropometric variables analyzed were: age, weight, height, and four skinfolds: subscapular, triceps, suprailiac and calf. Regarding anthropometric parameters, the referees had a mean age of 33.7 ± 3.1 years, height 177.9 ± 9.1 cm, weight 82.8 ± 12.8 kg and body fat of 15.5 ± 3.7%. The players had a mean age of 24.1 ± 3.4 years, weight of 78.1 ± 8.1 kg, height 178.2 ± 7.4 cm and body fat of 10.8 ± 2.6%. Functional evaluation showed that the average VO2max from referees and players were 50.0 ± 1.3 and 56.7 ± 5.8 ml.kg-1min-1, respectively. There is significant difference between the age (p = 0.0001), body fat percentage (p = 0.0002) and VO2max (p = 0.0011). It can be concluded that the referees are older and have a VO2max less than the players. This coupled with higher body fat percentage of the referees is a factor that impairs their performance during the games

El objetivo de este estudio fue analizar y comparar el VO2max. y el perfil antropométrico de árbitros y jugadores profesionales de futbol. La población de este estudio fue integrada por jugadores y árbitros profesionales filiales de la Federación Paranaense de Futbol (FPF). La muestra se compone de 10 árbitros del cuadro de arbitraje de la FPF y 24 jugadores de un equipo de primera división de futbol Paranaense, todos ellos de sexo masculino. Para la medición del VO2 max. se utilizó la prueba de campo de Leger. Las variables antropométricas estudiadas fueron: edad, peso corporal, altura y cuatro pliegues cutáneos (subescapular, triceps, suprailiaco y pantorrilla). Con relación a la evaluación antropométrica, los árbitros de la Federación Paranaense registraron una edad promedio de: 33,7 ± 3,1 años, altura de: 177,9 ± 9,1 cm, peso corporal: 82,8 ± 12,8 kg y grasa corporal de: 15,5 ± 3,7%. Mientras que los jugadores registraron una edad media de: 24,1 ± 3,4 años, peso corporal de: 78,1 ± 8,1 kg, altura de: 178,2 ± 7,4 cm y la grasa corporal de: 10,8 ± 2,6%. La evaluación funcional mostro que el VO2max. Promedio de los árbitros Paranaenses fue de: 50,0 ± 1,3 ml.kg-1 min-1 y los jugadores de: 56,7 ± 5,8 ml.kg-1 min-1. Los resultados han expresado que existe una diferencia estadísticamente significativa entre la edad (p = 0,0001), el porcentaje de grasa corporal (p = 0,0002) y el VO2max. (P = 0,0011). Después de analizar los datos de este estudio se puede concluir que los árbitros son: de mayor edad, tienen un VO2max. menor que de los jugadores y un porcentaje de grasa corporal superior en relación a los jugadores. Esta diferencia puede eventualmente poner en peligro el rendimiento del árbitro durante un partido de futbol