Aerobic Capacity of Preterm Children with Very Low Birth Weight at School Age and its Associated Factors / Capacidad aeróbica de niños prematuros de muy bajo peso al nacer y edad escolar y sus factores asociados

INTRODUCTION: Respiratory morbidities of preterm infants can cause significant ventilatory impairment thus compromising the aerobic capacity in childhood and adolescence. Therefore, the present study was conducted to evaluate the aerobic capacity in school age preterm children with VLBW and its associated factors. METHODS: A cross-sectional study was conducted among preterm born with VLBW and term children, both aged 6-9 years. An individualized symptom-limited treadmill testing protocol performed aerobic capacity. Measured variables: oxygen pulse (PuO2), percentage of maximum heart rate for age (%HR max), tidal volume/inspiratory capacity ratio (TV/IC), oxygen consumption (VO2) peak, and the ratio of the anaerobic threshold of gas exchange to the predicted percentage of maximum VO2 (VO2@LA/%VO2 max.pred.) were compared between groups. Univariate and multiple linear regression analyses were used to determine the factors associated with aerobic capacity. RESULTS: Thirty-four preterm and 32 term children were included. Similar VO2 peak and the other variables were observed. The development of bronchopulmonary dysplasia (BPD) and being obese/overweight was positively associated with %HR max. The Z-score for height/age and birth weight < 1000 g was positively associated with PuO2 and peak VO2, and negatively associated with overweight/obesity and female sex. CONCLUSIONS: Aerobic capacity was similar in both groups. Sex, development of BPD, birth weight < 1000 g and factors related to body growth, such as Z-score for height/age and overweight/obesity, were associated with aerobic capacity in preterm children with VLBW

INTRODUCCIÓN: Las enfermedades respiratorias de los niños prematuros pueden causar importantes impedimentos ventilatorios que comprometen la capacidad aeróbica en la infancia y en la adolescencia. El presente estudio se llevó a cabo para evaluar la capacidad aeróbica de niños prematuros en edad escolar de muy bajo peso al nacer (BPN) y los factores asociados. MÉTODOS: Se llevó a cabo un estudio transversal con niños prematuros de muy BPN y con niños a término, ambos grupos con edades comprendidas entre los 6 y 9 años. Las siguientes variables se compararon entre los 2 grupos: el pulso de oxígeno (PuO2), el porcentaje de frecuencia cardíaca máxima (%FC máx.), la relación entre el volumen corriente y la capacidad inspiratoria (TV/IC), el consumo pico de oxígeno (VO2) y la relación entre el umbral anaeróbico de intercambio de gas y el porcentaje estimado de VO2 máximo (VO2@LA/%VO2 máx. pred.). Se llevaron a cabo análisis de regresión lineal univariante y multivariante para determinar los factores asociados con la capacidad aeróbica. RESULTADOS: Se incluyeron 34 niños prematuros y 32 niños a término. Se registraron valores similares de VO2 pico y de otras variables. El desarrollo de displasia broncopulmonar (BPD) y de obesidad/sobrepeso mostró una asociación positiva con el %FC máx. El Z-score para la altura/edad y el peso al nacer < 1.000 g se asoció positivamente con la SaO2 y el VO2 y negativamente con el sobrepeso/obesidad y el sexo femenino. CONCLUSIONES: La capacidad aeróbica fue similar entre los 2 grupos. El sexo, el desarrollo de BPD, peso al nacer < 1.000 g y factores relacionados con el crecimiento corporal, tales como el Z-score para la altura/edad y para el sobrepeso/obesidad se asociaron con la capacidad aeróbica en niños prematuros de muy BPN

Use of a smartphone app combined with gamification to increase the level of physical activity of adults and older adults: protocol of a sequential multiple assignment randomized trial.

BACKGROUND: There is scientific evidence suggesting that app-based interventions targeted to increase the level of physical activity might be effective, although multicomponent interventions appear to be more effective than app-based interventions alone. Despite the motivating results, it remains unclear whether or not app-based interventions can increase the level of physical activity and cardiovascular health. Our study aims to investigate the effect of a smartphone app combined with gamification on the level of physical activity of adults and older adults. The specific aims are (1) to verify the effects of the intervention on cardiometabolic and cardiovascular health, lung function, and cardiorespiratory fitness; and (2) to verify the relationship between age group and the response rate. METHODS/DESIGN: We will conduct a sequential multiple assignment randomized trial (SMART). The adaptive intervention protocol will last 6 months. After baseline assessments, participants will be randomized into one of three groups (group 1: app + tailored messages; group 2: app + tailored messages + gamification I; control group: physical activity counseling). For 12 weeks, we will record the average number of steps per day of participants from groups 1 and 2. At 6 weeks from initiation of recording, participants will be classified into responders and non-responders according to their increase in the average number of daily steps; all those considered as non-responders will be re-randomized, with the chance to participate in a third group - group 3: app + tailored messages + gamification II. Finally, at 12 weeks, participants will continue using the app but will no longer receive direct intervention from investigators. All participants will be reassessed at 3 and 6 months from baseline. Our pilot SMART will require 42 participants (14 per arm). Following the SMART pilot, we will calculate the sample size for the trial based on the variation of the average number of steps/day, including an up to 40% loss to follow-up and a less optimistic nonresponse rate of 65%. DISCUSSION: To our knowledge, this will be the first trial with adaptive intervention to test the effectiveness of using a smartphone app to increase the level of physical activity of adults and older adults. TRIAL REGISTRATION: Brazilian Clinical Trials Registry: RBR-8xtc9c. Registered on 3 August 2018, http://www.ensaiosclinicos.gov.br; UTN number: U1111-1218-1092.