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Cinética do consumo de oxigénio : dimorfismo sexual / António José Santos
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Orientador(es)
Resumo(s)
A cinética do consumo do oxigénio (V̇ O2) comporta os mecanismos fisiológicos
subjacentes à resposta dinâmica do V̇ O2 perante a adaptação ao esforço, no início do
exercício ou em incrementos de intensidade e, ainda à correspondente recuperação.
Dadas as diferenças entre sexos que abarcam diversos fatores, sejam a nível
antropométrico, seja a respetiva composição corporal, sejam as diferenças hormonais,
entre outras, necessariamente tais diferenças são suscetíveis de manifestar
dissemelhanças entre os padrões que caraterizam o desempenho físico dos homens e
das mulheres. O presente trabalho teve por desiderato a comparação da cinética do
V̇ O2 pulmonar e muscular entre indivíduos do sexo masculino e feminino, relativamente
jovens, nos domínios de intensidade moderado e supramáximo. Não obstante as
dissemelhanças entre sexos, hipotetizou-se que estas que não seriam suficientes para
influir naquelas cinéticas. Para participar no presente estudo, foi recrutado um grupo de
34 sujeitos, 18 masculinos e 16 femininos. Numa primeira fase realizou-se um teste
progressivo máximo para determinar o V̇ O2max e ambos limiares ventilatórios,
identificando assim os domínios de intensidade. Com base nestes, realizaram-se dois
testes de transições. Em cada um deles, duas para o domínio moderado (80% do LV1)
e uma para o supramáximo (110% da VAM). Através da espectroscopia do
infravermelho próximo (NIRS) determinaram-se os parâmetros da cinética da oximetria
muscular naqueles dois domínios de intensidade no músculo vasto lateral.
Não se detetaram diferenças na constante temporal da cinética do V̇ O2 pulmonar, pese
embora os homens tenham apresentado amplitudes superiores nos domínios de
intensidade moderado (masculino: 26,80 ± 3,18; feminino: 24,45 ± 2,99, p < 0,05) e
supramáximo (masculino: 46,08 ± 7,51; feminino: 38,28 ± 4,20, p < 0,05).
The kinetics of oxygen consumption (V̇ O2) encompasses the physiological mechanisms underlying the dynamic response of V̇ O2 to adaptation to effort, at the start of exercise or in increments of intensity, and to the corresponding recovery. Given the differences between sexes that include various factors, whether anthropometric level, body composition, hormonal differences, among others, such differences are likely to manifest dissimilarities between the patterns characterizing the physical performance of men and women. This study aimed to compare the kinetics of pulmonary and muscular V̇ O2 between male and female individuals, relatively young, in moderate and supramaximal intensity domains. Despite the differences between sexes, it was hypothesized that these would not be sufficient to influence those kinetics. To participate in this study, a group of 34 subjects was recruited, 18 male and 16 female. In the first phase, a maximum progressive test was carried out to determine V̇ O2max and both ventilatory thresholds, thus identifying the intensity domains. Based on these, two transition tests were carried out. In each of them, two for the moderate domain (80% of LV1) and one for the supramaximal (110% of VAM). Through near-infrared spectroscopy (NIRS), the parameters of muscle oximetry kinetics in those two intensity domains in the vastus lateralis muscle were determined. No differences were detected in the temporal constant of pulmonary V̇ O2 kinetics, although men presented higher amplitudes in the moderate (male: 26.80 ± 3.18; female: 24.45 ± 2.99, p < 0.05) and supramaximal (male: 46.08 ± 7.51; female: 38.28 ± 4.20, p < 0.05) intensity domains.
The kinetics of oxygen consumption (V̇ O2) encompasses the physiological mechanisms underlying the dynamic response of V̇ O2 to adaptation to effort, at the start of exercise or in increments of intensity, and to the corresponding recovery. Given the differences between sexes that include various factors, whether anthropometric level, body composition, hormonal differences, among others, such differences are likely to manifest dissimilarities between the patterns characterizing the physical performance of men and women. This study aimed to compare the kinetics of pulmonary and muscular V̇ O2 between male and female individuals, relatively young, in moderate and supramaximal intensity domains. Despite the differences between sexes, it was hypothesized that these would not be sufficient to influence those kinetics. To participate in this study, a group of 34 subjects was recruited, 18 male and 16 female. In the first phase, a maximum progressive test was carried out to determine V̇ O2max and both ventilatory thresholds, thus identifying the intensity domains. Based on these, two transition tests were carried out. In each of them, two for the moderate domain (80% of LV1) and one for the supramaximal (110% of VAM). Through near-infrared spectroscopy (NIRS), the parameters of muscle oximetry kinetics in those two intensity domains in the vastus lateralis muscle were determined. No differences were detected in the temporal constant of pulmonary V̇ O2 kinetics, although men presented higher amplitudes in the moderate (male: 26.80 ± 3.18; female: 24.45 ± 2.99, p < 0.05) and supramaximal (male: 46.08 ± 7.51; female: 38.28 ± 4.20, p < 0.05) intensity domains.
Descrição
Palavras-chave
Cinética V̇ O2 pulmonar Oximetria muscular Domínio moderado Domínio supramáximo Espectroscopia do infravermelho próximo Masculino Feminino Amplitude Transições de intensidade Kinetics Pulmonary V̇ O2 Muscle oximetry Moderate domain Supramaximal domain Near-infrared spectroscopy Male Female Amplitude Intensity transitions