Percepção de esforço e desempenho no exercício de resistência: um estudo experimental em corredores de endurance profissionais sobre o efeito da fadiga mental e uma revisão sistemática com meta-análise sobre o papel da privação de sono
Data
2021-07-01
Orientadores
Silva, Bruno Moreira 
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Introdução: Existem situações dentro do contexto esportivo que podem induzir fadiga mental e gerar privação de sono nos atletas. Essas condições comprometem o desempenho no exercício de resistência, em parte pelo aumento da percepção de esforço. Entretanto, estudos sobre o desenvolvimento da fadiga mental e seus consequentes efeitos sobre o exercício de resistência são escassos em atletas de endurance profissionais. E, além disso, o papel do sexo nesse contexto é desconhecido. Embora extensivamente investigada, ainda não existe uma síntese sistemática e metanalítica da literatura reportando o efeito da privação de sono sobre o desempenho no exercício de resistência, bem como quais fatores poderiam influenciá-lo. Objetivos: O primeiro estudo teve como objetivo investigar experimentalmente se 45 min de atividade cognitiva envolvendo respostas conflitantes 1) induziria fadiga mental em corredores de endurance profissionais; 2) alteraria as respostas psicofisiológicas e o desempenho em um subsequente exercício de resistência; e 3) se esses efeitos seriam influenciados pelo sexo. O segundo estudo teve como objetivo realizar uma revisão sistemática e meta-análise para investigar 1) quanto a privação de sono piora o desempenho no exercício de resistência e 2) se tal efeito é influenciado pelo estado de treinamento aeróbio, características do exercício e pela magnitude da privação de sono. Métodos: no primeiro estudo (i.e., estudo experimental), 31 corredores de endurance profissionais (15 mulheres) realizaram 45 min da tarefa Stroop cor-palavra ou assistiram 45 min de um documentário de maneira aleatória, cruzada e cega. Medidas perceptuais e o desempenho cognitivo foram obtidas para avaliar a indução de fadiga mental. Depois disso, os atletas realizaram um teste de tempo até a exaustão (TTE) em esteira no domínio severo de intensidade de exercício. Medidas psicofisiológicas foram obtidas do TTE. No segundo estudo (i.e., revisão sistemática e meta-análise), as bases de dados Pubmed, Web of Science, Embase e Scopus foram sistematicamente revisadas em julho de 2020 e março de 2021 para encontrar estudos controlados randomizados e não-randomizados em humanos saudáveis que investigaram o efeito da privação parcial ou total do sono sobre desempenho em testes de exercício incremental, testes de carga constante ou testes contrarrelógio. A diferença média padronizada (DMP) corrigida (g de Hedges) e seu intervalo de confiança de 95% (IC95%) foram calculados entre o desempenho no exercício de resistência na condição de privação de sono e controle (i.e., noite completa de sono). Um modelo de efeito aleatório calculou o efeito total (i.e., DMP agrupada e IC95%). O viés de publicação foi avaliado pelo teste do intercepto de Egger e corrigido pelo método de aparar e preencher. Um modelo de efeito misto avaliou os efeitos dos subgrupos. Resultados: No estudo experimental, as medidas perceptuais e o desempenho cognitivo indicaram que a atividade cognitiva prolongada induziu fadiga mental (P < 0,05). As respostas cardiorrespiratórias e metabólicas durante o exercício não mudaram de maneira importante em virtude da fadiga mental gerada pela atividade cognitiva (P > 0,05). Entretanto, a máxima percepção de esforço foi atingida antecipadamente (P < 0,05), piorando o desempenho no TTE (P < 0,05; média ± desvio padrão; -27 ± 81 s e -27 ± 60 s nas mulheres e homens, respectivamente). Esses efeitos não foram influenciados pelo sexo. Na revisão sistemática e meta-análise, os 25 estudos analisados (32 DMP) mostraram que a privação de sono tem um efeito negativo pequeno sobre o desempenho no exercício de resistência (DMP agrupada [IC95%]; -0,46 [-0,61; -0,31]; P < 0,001; Q = 28,25; df = 31; P = 0,608; I2 = 0% [0%; 33,8%]). Esse efeito não foi afetado depois de corrigido o viés de publicação (-0,43 [-0,58; -0,28]; P < 0,001; Q = 33,95, df = 33, P = 0,422; I2 = 2,8% [0%; 40,4%]). Não houve diferença entre os subgrupos analisados (valores de P entre 0,141 e 0,961). Conclusões: A presente tese mostrou que corredores de endurance profissionais, independente do sexo, estão sujeitos à queda do desempenho no exercício de resistência quando expostos à uma tarefa cognitiva prolongada envolvendo respostas conflitantes. Essa piora não foi acompanhada por alterações cardiorrespiratórias ou metabólicas, mas sim por aumento da percepção de esforço. Portanto, esses dados sugerem que a percepção de esforço foi um fator limitante do desempenho no exercício de resistência. Em adição, observou-se na revisão sistemática e meta-analítica da literatura que a privação do sono, uma condição que normalmente provoca aumento da percepção de esforço durante o exercício, gera um comprometimento pequeno sobre o desempenho no exercício de resistência. Tal efeito, por sua vez, não foi influenciado pelo estado de treinamento aeróbio, características do exercício ou pela magnitude da privação de sono.
Introduction: Some sport context situations can induce mental fatigue and generate sleep deprivation in athletes. These conditions compromise endurance exercise performance, in part by the increase in perception of effort. However, studies on the development of mental fatigue and its consequent effects on endurance exercise are scarce in professional endurance athletes, and the role of sex in this context is unknown. Although extensively investigated, there is still no systematic and meta-analytical synthesis of the literature reporting the sleep deprivation's effect on endurance exercise performance, as well as what factors could influence it. Objectives: The first study had the following objectives: to experimentally investigate whether 45 min of prolonged cognitive activity involving conflicting responses 1) would induce mental fatigue in professional endurance runners; 2) would alter psychophysiological responses and performance in a subsequent endurance exercise; and 3) whether sex would influence in these effects. The second study aimed at carrying out a systematic review and meta-analysis to investigate 1) whether sleep deprivation worse endurance exercise performance and 2) whether aerobic training status, exercise characteristics, and the magnitude of sleep deprivation would influence such effect. Methods: In the first study (i.e., experimental study), 31 professional endurance runners (15 women) carried out 45 min of Stroop color-word task or watching 45 min of an emotionally neutral documentary in a randomized, crossed-over, and single-blind way. Perceptual measures and cognitive performance were obtained to assess mental fatigue induction. Thereafter, subjects carried out a time-to-exhaustion treadmill test (TTE) in the severe exercise intensity domain. Psychophysiological measures were obtained from the TTE. In the second study (i.e., systematic review and meta-analysis), Pubmed, Web of Science, Embase, and Scopus database were systematically reviewed in July 2020 and March 2021 to find controlled randomized and non-randomized studies in healthy humans that investigated the effect of partial or total sleep deprivation on endurance exercise performance (i.e., incremental, constant-load, or time trial tests). Standardized mean difference (SMD) as Hedges’ g and 95% confidence interval (95%CI) were calculated for endurance exercise performance between the sleep deprivation and control (i.e., full-sleep night) conditions. A random-effects model calculated the overall effect (i.e, pooled SMD and 95%CI). Publication bias was assessed by Egger’s test of the intercept and corrected by the trim-and-fill method. A mixed-effects model analyzed subgroups' effects. Results: In the experimental study, perceptual measures and cognitive performance indicated mental fatigue was induced by prolonged cognitive activity (P < 0.05). Cardiorespiratory and metabolic responses to exercise did not change importantly because of the prolonged cognitive activity (P > 0.05). However, the maximal perceived effort was attained earlier (P < 0.05), worsening the TTE test performance (P < 0.05; mean ± standard deviation: -27 ± 81 s and -27 ± 60 s for women and men, respectively). These effects were not influenced by sex (P > 0.05). In the systematic review and meta-analysis, the 25 analyzed studies (32 SMD) showed sleep deprivation generates a small negative effect on endurance exercise performance (pooled SMD [95%CI] = -0.46 [-0.61; -0.31]; Q = 28.25, df = 31, P = 0.608; I2 = 0% [0%; 33.8%]). The effect magnitude was not affected by publication bias correction (-0.43 [-0.58; -0.28]; Q = 33.95, df = 33, P = 0.422; I2 = 2.8% [0%; 40.4%]). Subgroup analyses were not statistically significant (P = 0.141 to 0.961). Conclusions: The present thesis showed that professional endurance runners, regardless of sex, may worse endurance exercise performance when exposed to a prolonged cognitive task involving conflicting responses. This worsening was not accompanied by cardiorespiratory or metabolic changes, but by an increased perception of effort. Therefore, these data suggest that the perception of effort was a limiting factor of endurance exercise performance. In addition, it was observed in the systematic and meta-analytical review of the literature that sleep deprivation, a condition that normally causes an increase in perception of effort during exercise, generates a small impairment on endurance exercise performance. Such effect, in turn, was not influenced by the aerobic training status, exercise characteristics, or the magnitude of sleep deprivation.
Introduction: Some sport context situations can induce mental fatigue and generate sleep deprivation in athletes. These conditions compromise endurance exercise performance, in part by the increase in perception of effort. However, studies on the development of mental fatigue and its consequent effects on endurance exercise are scarce in professional endurance athletes, and the role of sex in this context is unknown. Although extensively investigated, there is still no systematic and meta-analytical synthesis of the literature reporting the sleep deprivation's effect on endurance exercise performance, as well as what factors could influence it. Objectives: The first study had the following objectives: to experimentally investigate whether 45 min of prolonged cognitive activity involving conflicting responses 1) would induce mental fatigue in professional endurance runners; 2) would alter psychophysiological responses and performance in a subsequent endurance exercise; and 3) whether sex would influence in these effects. The second study aimed at carrying out a systematic review and meta-analysis to investigate 1) whether sleep deprivation worse endurance exercise performance and 2) whether aerobic training status, exercise characteristics, and the magnitude of sleep deprivation would influence such effect. Methods: In the first study (i.e., experimental study), 31 professional endurance runners (15 women) carried out 45 min of Stroop color-word task or watching 45 min of an emotionally neutral documentary in a randomized, crossed-over, and single-blind way. Perceptual measures and cognitive performance were obtained to assess mental fatigue induction. Thereafter, subjects carried out a time-to-exhaustion treadmill test (TTE) in the severe exercise intensity domain. Psychophysiological measures were obtained from the TTE. In the second study (i.e., systematic review and meta-analysis), Pubmed, Web of Science, Embase, and Scopus database were systematically reviewed in July 2020 and March 2021 to find controlled randomized and non-randomized studies in healthy humans that investigated the effect of partial or total sleep deprivation on endurance exercise performance (i.e., incremental, constant-load, or time trial tests). Standardized mean difference (SMD) as Hedges’ g and 95% confidence interval (95%CI) were calculated for endurance exercise performance between the sleep deprivation and control (i.e., full-sleep night) conditions. A random-effects model calculated the overall effect (i.e, pooled SMD and 95%CI). Publication bias was assessed by Egger’s test of the intercept and corrected by the trim-and-fill method. A mixed-effects model analyzed subgroups' effects. Results: In the experimental study, perceptual measures and cognitive performance indicated mental fatigue was induced by prolonged cognitive activity (P < 0.05). Cardiorespiratory and metabolic responses to exercise did not change importantly because of the prolonged cognitive activity (P > 0.05). However, the maximal perceived effort was attained earlier (P < 0.05), worsening the TTE test performance (P < 0.05; mean ± standard deviation: -27 ± 81 s and -27 ± 60 s for women and men, respectively). These effects were not influenced by sex (P > 0.05). In the systematic review and meta-analysis, the 25 analyzed studies (32 SMD) showed sleep deprivation generates a small negative effect on endurance exercise performance (pooled SMD [95%CI] = -0.46 [-0.61; -0.31]; Q = 28.25, df = 31, P = 0.608; I2 = 0% [0%; 33.8%]). The effect magnitude was not affected by publication bias correction (-0.43 [-0.58; -0.28]; Q = 33.95, df = 33, P = 0.422; I2 = 2.8% [0%; 40.4%]). Subgroup analyses were not statistically significant (P = 0.141 to 0.961). Conclusions: The present thesis showed that professional endurance runners, regardless of sex, may worse endurance exercise performance when exposed to a prolonged cognitive task involving conflicting responses. This worsening was not accompanied by cardiorespiratory or metabolic changes, but by an increased perception of effort. Therefore, these data suggest that the perception of effort was a limiting factor of endurance exercise performance. In addition, it was observed in the systematic and meta-analytical review of the literature that sleep deprivation, a condition that normally causes an increase in perception of effort during exercise, generates a small impairment on endurance exercise performance. Such effect, in turn, was not influenced by the aerobic training status, exercise characteristics, or the magnitude of sleep deprivation.
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Citação
LOPES, Thiago Ribeiro. Percepção de esforço e desempenho no exercício de resistência: um estudo experimental em corredores de endurance profissionais sobre o efeito da fadiga mental e uma revisão sistemática com meta-análise sobre o papel da privação de sono. São Paulo, 2021. 201 p. Tese (Doutorado em Medicina Translacional) - Universidade Federal de São Paulo (UNIFESP), São Paulo, 2021.