Efeito de uma intervenção com abordagem motivacional sobre capacidade de exercício em adolescentes com sobrepeso e obesidade

Abstract

Obesity is a chronic disease that is growing worldwide and, as a result of its coverage, has developed almost an epidemic and it is becoming one of the most relevant public health problems nowadays, since it is a risk factor that can trigger diseases. Thus, this study aimed to evaluate the effect of an interdisciplinary intervention with a motivational approach on exercise capacity and habitual physical activity levels in overweight and obese adolescents. This is a randomized controlled trial with single blinding of individuals. Adolescents aged 15 to 18 years and body mass index (BMI) compatible with overweight or obesity (≥ 85th percentile and ≤99.9th percentile) were included. The present study was approved by the Research Ethics Committee of the University (CAAE: 36209814.6.0000.5336) and all parents and/or guardians signed the informed consent form (ICF) and the students signed the assent form (AF). After the initial interest, individuals were invited by telephone to participate in a screening and then randomized through the Random Allocation Software (version 2.0) to participate in one of the following two groups: traditional approach (control) or motivational interview (intervention) aiming at the modification of lifestyle. In the control group (GC) the focus was the development of skills through educational health actions using the transmission pedagogy. In the intervention group (GI) the Transtheoric Model of Change was used along with the Motivational Interview to try to develop skills through educational actions in health that provided the development of autonomy and empowerment for behavior change, based on interdisciplinary motivational strategies. Subsequently, the initial evaluations, including the cardiopulmonary exercise test (CPET) and the levels of physical activity were assessed using a short questionnaire and an objective measure (pedometer). The evaluations were performed in two moments for both groups, at time zero (time of inclusion in the study) and after three months (end of intervention). Of a total of 43 overweight and obese adolescents, 05 were excluded, resulting in a sample of 37 participants, 18 in the GC and 19 in the GI. The mean age was around 17 years, with a predominance of females. The mean BMI (z score) was about 2, with 17 being overweight and 20 being obese. There were no significant differences in the baseline demographic, anthropometric and physical activity characteristics between groups. The motivational intervention did not cause significant differences (p>0.05) in the comparison of the variables of exercise capacity and habitual physical activity (questionnaire and pedometer) between GC and GI. The mean VO2max (mL/kg/min) at peak exercise was about 26.0, while the VO2max (mL/kg/min) at the anaerobic threshold (LA) was close to 22.0. All cardiovascular, metabolic, ventilatory and subjective variables at peak exercise were similar in both groups, except for Vmax that was significantly higher (p=0.001) in GI compared to GC. When we tested the effect of the motivational interview on nutritional status (weight and BMI) and physical fitness assessed by CPET (VEmax, VO2max, VO2max in AT and ventilatory equivalents) again no significant changes were observed. The results allow us to conclude that the intervention with a motivational approach did not alter physical fitness and habitual physical activity levels in overweight and obese adolescents.