Acute physiological responses to "recovery intermittent hypoxia" in hiit / Respuestas agudas a la "hipoxia intermitente de recuperación" en el hiit / Respostas fisiológicas agudas à "hipóxia intermitente de recuperação" no hiit

ABSTRACT Introduction: Traditional intermittent hypoxia training improves sport performance after short periods of exposure, but acute exposure to intermittent hypoxia leads to decreased training intensity and technical quality. The solution to overcome these negative effects may be to perform efforts in normoxia and the intervals between efforts in hypoxia, maintaining the quality of training and the benefits of hypoxia. Objective: This study aimed to evaluate the acute physiological responses to hypoxia exposure during recovery between high intensity efforts. Materials and methods: Randomized, one-blind, placebo-controlled study. Sixteen men performed a graded exercise test to determine their maximal intensity and two sessions of high-intensity interval training. The training intervals could be in hypoxia (HRT), FIO2: 0.136 or normoxia (NRT), FIO2: 0.209. During the two-minute interval between the ten one-minute efforts, peripheral oxygen saturation (SpO2), heart rate (HR), blood lactate ([La]), blood glucose ([Glu]) were constantly measured. Results: There were differences in HR (TRN = 120 ± 14 bpm; TRH = 129 ± 13 bpm, p < 0.01) and SpO2 (TRN = 96.9 ± 1.0%; TRH = 86.2 ± 3.5%, p < 0.01). No differences in [La] and [Glu] TRN (4.4 ± 1.7 mmol.l-1; 3.9 ± 0.5 mmol.l-1) and TRH (5.2 ± 2.0 mmol.l-1; 4.0 ± 0.8 mmol.l-1, p = 0.17). Conclusion: The possibility of including hypoxia only in the recovery intervals as an additional stimulus to the training, without decreasing the quality of the training, was evidenced. Level of Evidence II; Randomized Clinical Trial of Minor Quality.

RESUMEN Introducción: El entrenamiento tradicional en hipoxia intermitente mejora el rendimiento deportivo tras cortos periodos de exposición, sin embargo, la exposición aguda a la hipoxia intermitente conduce a una disminución de la intensidad del entrenamiento y de la calidad técnica. La solución para superar estos efectos negativos puede ser realizar los esfuerzos en normoxia y los intervalos entre esfuerzos en hipoxia, manteniendo la calidad del entrenamiento y los beneficios de la hipoxia. Objetivo: Este estudio pretendía evaluar las respuestas fisiológicas agudas a la exposición a la hipoxia durante la recuperación entre esfuerzos de alta intensidad. Materiales y métodos: Estudio aleatorizado, a ciegas y controlado con placebo. Dieciséis hombres realizaron una prueba de ejercicio graduado para determinar su intensidad máxima y dos sesiones de entrenamiento por intervalos de alta intensidad. Los intervalos de entrenamiento podían ser en hipoxia (HRT), FIO2: 0,136 o normoxia (NRT), FIO2: 0,209. Durante el intervalo de dos minutos entre los diez esfuerzos de un minuto, se midieron constantemente la saturación periférica de oxígeno (SpO2), la frecuencia cardiaca (FC), el lactato en sangre ([La]) y la glucemia ([Glu]). Resultados: Hubo diferencias en la FC (TRN = 120 ± 14 lpm; TRH = 129 ± 13 lpm, p < 0,01) y la SpO2 (TRN = 96,9 ± 1,0%; TRH = 86,2 ± 3,5%, p < 0,01). No hubo diferencias en [La] y [Glu] TRN (4,4 ± 1,7 mmol.l-1; 3,9 ± 0,5 mmol.l-1) y TRH (5,2 ± 2,0 mmol.l-1; 4,0 ± 0,8 mmol.l-1, p = 0,17). Conclusión: Se evidenció la posibilidad de incluir hipoxia sólo en los intervalos de recuperación como estímulo adicional al entrenamiento sin disminuir la calidad del mismo. Nivel de Evidencia II; Ensayo Clínico Aleatorizado de Baja Calidad.

RESUMO Introdução: O treinamento de hipóxia intermitente tradicional melhora o desempenho esportivo após curtos períodos de exposição, porém a exposição aguda à hipóxia intermitente leva à diminuição da intensidade do treinamento e da qualidade técnica. A solução para superar esses efeitos negativos pode ser realizar esforços em normóxia e os intervalos entre os esforços em hipóxia, mantendo a qualidade do treinamento e os benefícios da hipóxia. Objetivo: Este estudo teve como objetivo avaliar as respostas fisiológicas agudas à exposição de hipóxia durante a recuperação entre esforços de alta intensidade. Materiais e métodos: Estudo aleatório e one-blinded, com efeito placebo controlado. Dezesseis homens realizaram um teste de exercício graduado para determinar sua intensidade máxima e duas sessões de treinamento intervalado de alta intensidade. Os intervalos de treinamento podem ser em hipóxia (TRH), FIO2: 0,136 ou normóxia (TRN), FIO2: 0,209. Durante os dois minutos de intervalo entre os dez esforços de um minuto, foram medidos constantemente a saturação periférica de oxigênio (SpO2), frequência cardíaca (FC), lactato sanguíneo ([La]), glicemia ([Glu]). Resultados: Houve diferenças na FC (TRN = 120 ± 14 bpm; TRH = 129 ± 13 bpm, p <0,01) e SpO2 (TRN = 96,9 ± 1,0%; TRH = 86,2 ± 3,5%, p <0,01). Sem diferenças em [La] e [Glu] TRN (4,4 ± 1,7 mmol.l-1; 3,9 ± 0,5 mmol.l-1) e TRH (5,2 ± 2,0 mmol.l-1; 4,0 ± 0,8 mmol.l-1, p = 0,17). Conclusão: Evidenciou-se a possibilidade de incluir a hipóxia apenas nos intervalos de recuperação como um estímulo adicional ao treinamento, sem diminuir a qualidade do treinamento. Nível de Evidência II; Estudo Clínico Randomizado de Menor Qualidade.

Influence of photobiomodulation therapy on the physical performance of women during the follicular phase of the menstrual cycle: A double-blind Sham-controlled randomized clinical trial.

To evaluate the effects of photobiomodulation on the physical performance of healthy women, considering the menstrual cycle. 27 physically active healthy women (age 25.68 ± 3.99 years; mass 63.76 ± 12.77 kg; height 1.65 ± 0.59 cm) during the initial follicular phase (FF1 and FF2) of the menstrual cycle underwent performance evaluations, through a supramaximal test, subjective perception of exertion, blood lactate, and evaluations in the isokinetic dynamometer. Photobiomodulation (PBM) (200J) and Sham (0J) therapy were applied 10 min before the performance evaluations on the quadriceps femoris, hamstrings, and triceps surae muscles. A significance level of 5% was adopted and the effect size was calculated by Cohen's d. It was not possible to observe a significant difference (p > 0.05) in any of the performance variables evaluated in the comparison between groups, only small effects for total distance, final subjective perception of exertion, lactate peak and lactate delta in the PBM group. PBM did not improve muscle performance, resistance to fatigue, perceived exertion, and blood lactate concentrations during a predominantly anaerobic test in healthy women during the FF of the menstrual cycle.

Interaction predictors of self-perception menstrual symptoms and influence of the menstrual cycle on physical performance of physically active women.

OBJECTIVE: To analyze the physical performance, self-perception menstrual symptoms, of physically active eumenorrheic women with endogenous ovarian cycle in two phases of the menstrual cycle. METHODS: Twenty-six women participated in the study (age 25.8 ± 3.9 years; height 1.64 ± 0.58 m; mass 64 ± 12.32 kg; menarche 11.69 ± 1.28 years). Assessments were performed in two phases of the menstrual cycle (MC), Early-Follicular Phase (FP) and Mid-Luteal Phase (LP), performance was assessed through total time to exhaustion (TTE), complete stages (CE), and final speed (FE), through a graded exercise test (GXT). Information on the participants' menstrual symptoms and their perceptions of the influence of MC on their performance were also collected. Data normality was assessed using the Shapiro-Wilk test. Paired analyses were conducted (t test or Wilcoxon) to examine the responses between the menstrual phases. The interaction analysis of symptom predictors was performed by multiple linear regression, with a significance level of p ≤ 0.05. RESULTS: There was no significant difference in physical performance between the phases during the GXT in TTE (mean difference 8.50; 95% CI - 11.99 to 42; p = 0.36). During FP, women with heavy flow had shorter performance in the GXT (t = - 2.5; p = 0.01), demonstrating an r2 = 0.32. In LP, for the women who reported not having the perception of the influence of the menstrual cycle on exercise, the total test time was longer (t = 2.55; p = 0.01), with an r2 = 0.45. CONCLUSION: There was no difference in physical performance between FP and LP. However, menstrual flow intensity and perception of cycle interference demonstrated a decrease in TTE.

Can Hypoxia Alter the Anaerobic Capacity Measured by a Single Exhaustive Exercise?

The present study aimed to compare the MAODALT in situations of hypoxia and normoxia to confirm the method validity. Seventeen healthy and physically active men participated in this study, aged 25.2±3.2 years. All participants underwent four days of evaluation. The first day was performed a body composition test, an incremental test to exhaustion to determine the maximum oxygen uptake, familiarizing the hypoxia (H) and normoxia (N) situation and the equipment used. On the second, third and fourth days, supramaximal efforts were performed until exhaustion at 110% of maximum oxygen uptake, in a situation of hypoxia (FIO2=14.0%) and normoxia (FIO2=20.9%). The anaerobic capacity was considered the sum of energy supply of the alactic and lactic systens. The absolute or relative anaerobic capacity values were not different (H=3.9±1.1 L, N=3.8±0.9 L, p=0.69), similarly no differences were found for the alactic contribution (H=1.7±0.5 L, N=1.5±0.5 L, p=0.30) and lactic contribution (H=2.3±0.9 L, N=2.3±0.7 L, p=0.85). It can be concluded that the anaerobic capacity measured by a single exhaustive effort is not altered by hypoxia.

Effectiveness, implementation, and monitoring variables of intermittent hypoxic bicycle training in patients recovered from COVID-19: The AEROBICOVID study.

Hypoxic exposure is safely associated with exercise for many pathological conditions, providing additional effects on health outcomes. COVID-19 is a new disease, so the physiological repercussions caused by exercise in affected patients and the safety of exposure to hypoxia in these conditions are still unknown. Due to the effects of the disease on the respiratory system and following the sequence of AEROBICOVID research work, this study aimed to evaluate the effectiveness, tolerance and acute safety of 24 bicycle training sessions performed under intermittent hypoxic conditions through analysis of peripheral oxyhemoglobin saturation (SpO2), heart rate (HR), rate of perceived exertion (RPE), blood lactate concentration ([La-]) and symptoms of acute mountain sickness in patients recovered from COVID-19. Participants were allocated to three training groups: the normoxia group (GN) remained in normoxia (inspired fraction of O2 (FiO2) of ∼20.9%, a city with 526 m altitude) for the entire session; the recovery hypoxia group (GHR) was exposed to hypoxia (FiO2 ∼13.5%, corresponding to 3,000 m altitude) all the time except during the effort; the hypoxia group (GH) trained in hypoxia (FiO2 ∼13.5%) throughout the session. The altitude simulation effectively reduced SpO2 mean with significant differences between groups GN, GHR, and GH, being 96.9(1.6), 95.1(3.1), and 87.7(6.5), respectively. Additionally, the proposed exercise and hypoxic stimulus was well-tolerated, since 93% of participants showed no or moderate acute mountain sickness symptoms; maintained nearly 80% of sets at target heart rate; and most frequently reporting session intensity as an RPE of "3" (moderate). The internal load calculation, analyzed through training impulse (TRIMP), calculated using HR [TRIMPHR = HR * training volume (min)] and RPE [TRIMPRPE = RPE * training volume (min)], showed no significant difference between groups. The current strategy effectively promoted the altitude simulation and monitoring variables, being well-tolerated and safely acute exposure, as the low Lake Louise scores and the stable HR, SpO2, and RPE values showed during the sessions.

Physical activity in the post-COVID-19: AEROBICOVID project design and perspectives / Atividade física no pós-COVID-19: escopo do projeto AEROBICOVID e suas perspectivas

During the COVID-19 pandemic, several late-onset impairments have been observed, affecting the health and functionality of those involved. On the other hand, lower SARS-CoV-2 infection rates and severity of symptoms were observed in high-altitude cities. In this sense, the AEROBICOVID project was developed with the hypothesis that exercise would be an important opportunity for health improvement and that hypoxia would promote additional benefits in the recovery process. The cohort was about 84 participants with approximately 30 days since the COVID-19 symptoms recovery, 25 in the control group, and 59 divided into three moderate physical training groups. The project had good results in teaching, research, and extension, but also faced difficulties in operationalization. This experience is the basis for future proposals through an extension project at the University of São Paulo and in a Family Health Unit, besides a research project that will develop a new low-cost hypoxia technology (AU)

Durante a pandemia de COVID-19 estão sendo observados vários efeitos tardios, afetando a saúde e a funcionalidade dos acometidos. Por outro lado, foram observadas menores taxas de infecção pelo SARS-CoV-2 e gravidade dos sintomas em cidades de elevada altitude. Neste sentido, o projeto AEROBICOVID foi desenvolvido com a hipótese de que o exercício seria uma proposta importante para a melhoria da saúde e que a hipóxia promoveria benefícios adicionais no processo de recuperação. Participaram 84 pessoas com aproximadamente 30 dias desde a recuperação dos sintomas da COVID-19, 25 no grupo de controle e 59 divididos em três grupos de treinamento físico moderado. O projeto teve bons resultados no ensino, pesquisa e extensão, mas também enfrentou dificuldades na operacionalização. Estas experiências são a base para propostas futuras através de um projeto de extensão na Universidade de São Paulo e em uma Unidade de Saúde da Família, além de um projeto de pesquisa que desenvolverá uma nova tecnologia de hipóxia de baixo custo (AU)

Proposal of a New Specific Test to Assess the Aerobic Performance in Judo.

Purpose: Judo is an intermittent sport, dependent on anaerobic metabolism as well as aerobic metabolism to generate energy during a match; however, there are few reliable tests to measure specific aerobic performance in judo. Thus, the present study aimed to propose a new specific and indirect method to assess the aerobic performance in judo athletes; it determined the inter-rater and test-retest reliability of this new protocol and correlated the new protocol with a valid laboratory test. Method: The participants included 15 men, athletes of judo (age average: 21.59 ± 4.60 years, weight: 80.71 ± 15.93 kg and height: 173.2 ± 6.84 cm). The participants performed three tests: the first test was a graded exercise test (GXT) and the second and third tests were the Judo Aerobic Test (JAT). Results: The test presented high test-retest and inter-rater reliability, the intraclass correlation coefficients (ICC) ranking of 0.68-0.96, the correlation values ranging from .77 to .96, and no statistical differences between means in test and retest (p > .05). The standard error of measurement and the coefficient of variation between raters presented lower than 10%, indicating reproducibility. Moderate and strong correlations were found between JAT and GXT variables. Conclusion: We concluded that the test presents excellent inter-rater and test-retest reliability and a moderate correlation with GXT.