Intensity and Duration of Physical Activity and Cardiorespiratory Fitness

Abstract

OBJECTIVES: There is no clear guidance on the intensity and duration of physical activity (PA) that adolescents require to maximise cardiorespiratory fitness (CRF). We aimed to determine the strength of associations between each PA intensity and CRF, independently of other intensities, and the PA duration at each intensity associated with maximal CRF. METHODS: PA and CRF were assessed in 339 adolescents aged 13 to 14 years by wrist-worn accelerometers and 20-m shuttle runs, respectively. Partial regression modeling was used to construct residualized PA variables at each PA intensity that were uncorrelated with each other. Moving average models were optimally fitted to determine relationships between residualized PA variables and CRF. Threshold regression models determined the duration of PA above which CRF improvement was minimal. RESULTS: Greater vigorous PA (VPA) was associated with better CRF until about 20 minutes of daily VPA, when the relationship plateaued. Moderate and light PA, and sedentary time were not associated with CRF in partial models. Adolescents performing 14 (range 12–17) minutes of daily VPA had median CRF. Participants in the upper quartile of VPA had 1.03 z-scores higher CRF than those in the lowest quartile (95% confidence interval: 0.75 to 1.30). CONCLUSIONS: Our data suggest that 20 minutes of daily VPA may be best for maximizing CRF in adolescence. As moderate-to-vigorous PA guidelines can be satisfied by only undertaking moderate PA, with no apparent independent benefit, we suggest that future guidelines focus on VPA alone, simplifying public health messaging.

Heteroatoms (Si, B, N, and P) doped 2D monolayer MoS2for NH3gas detection

“…From the literature, it has been found that the higher the magnitude of the negative of E ad , the longer the recovery time. 52,53 Hence in this study a higher negative adsorption energy was observed for P@MoS 2 _NH 3 , which shows it could be useful as a sensor material.…”

Stance of Sports and Fitness: A Scientometric Review

“…Meanwhile, the hot topic is cardiorespiratory fitness. The results of research conducted by Burden et al (2022) show that adolescents who engage in 20 minutes of vigorous physical activity per day on average have maximal cardiorespiratory fitness, and there is little evidence that engaging in more or less intense physical activity is beneficial. In addition to always being related to physical health and fitness, cardiorespiratory fitness is also related to cognitive function and psychological well-being.…”

Que Intensidade e Duração para o Exercício do Jovem?

“…4 Estes indicadores realçam o declínio da prática de exercício físico nos jovens em geral, realçando-se a exceção dos estudantes do sexo feminino nas escolas secundárias, os quais têm aumentado a participação desportiva, pelo menos até 2015, ano em que foi publicado o estudo de Basett D R e colaboradores. 5 A AFCR é um importante determinante da saúde e, apesar da genética ser importante para a sua definição 6 , ela pode ser melhorada também nas escolas através do exercício físico 7 , o qual é o principal fator modificável. Dobbins M e colaboradores, do Canadá, publicaram uma revisão sistemática sobre a evidência da eficácia de intervenções na escola para a promoção da atividade física e aptidão em crianças e adolescentes (6-18 anos de idade).…”

“…Esta informação é muito importante pois é referido na Discussão que a maioria dos adolescentes falha o objetivo de exercício durante 60 minutos com intensidade moderada / alta e o período de 20 minutos é mais fácil de incluir na rotina quotidiana. Também nesta secção, os autores discutem a validade do teste de vaivém como instrumento de avaliação da AFCR, referindo que a avaliação direta do VO 2 máximo seria mais desejável 7 , mas com praticabilidade bastante inferior em população sob estudo tão numerosa.…”