Efeitos de uma intervenção com exercício físico e aconselhamento em saúde no comportamento sedentário de adolescentes

Abstract

The time spent by adolescents in sedentary behavior (SB) has increased due to the use of screen devices and causes serious health damage. The present work aimed to I) describe methodological aspects of SB research and identify interventions to reduce SB in adolescents, II) to verify the effectiveness of an extracurricular physical exercise program and health counseling in reducing SB of adolescents from Uberaba, Minas Gerais. To achieve the first objective, a systematic review was performed with data search from 2014 to April 2019, in LILACS, Pubmed, SciELO and Scopus. Systematic reviews and meta-analyzes were excluded. We included 38 articles in the qualitative synthesis. Only five papers presented experimental design. Screen time was the most commonly used indicator for SB measurement. 23 different cutoff points were found, which makes it difficult to compare results between surveys. Only 13.1% of the studies used objective measures to estimate the SB. The use of objective measures to obtain more reliable information needs to be encouraged. More experiments are needed to reduce SB in adolescents. To reach the second objective, a physical exercise program and health counseling were conducted with adolescent students from a public school in Uberaba, Minas Gerais. The intervention lasted 12 weeks and included physical exercises and actions such as sending messages via WhatsApp and displaying posters. Height, waist circumference, body mass, skinfold thickness, body composition, blood pressure, cardiorespiratory fitness and biochemical markers were evaluated. The SB was measured by self-report and accelerometer. Repeated measures analysis of variance (ANOVA) and significance level α = 5% were applied. Participated n = 19 adolescents, allocated in intervention group (IG, n = 10) and control group (CG, n = 9). The mean age was IG = 14.20 (sd = 1.03) and CG = 13.89 (sd = 1.26) years. Post-intervention there was significant difference in the triceps skinfold thickness, time effect (F(1.0) = 9.950; p = 0.006) and time*group interaction for triceps skinfolds (F(1.0) = 4.601; p = 0.047), subscapular (F(1.0) = 16.430; p = 0.001), suprailiac (F (1.0) = 9.651 ; p = 0.006) and cardiorespiratory fitness (F(1.0) = 9.346; p = 0.008). Total cholesterol (F(1.0) = 22.013; p = 0.000) and LDL -c (F(1.0) = 5.836; p = 0.029) showed difference between the times. The accelerometer showed significant difference between the groups in the sum of time in weekly SB (F(1) = 6.326; p = 0.024), in the weekly SB average (F(1) = 5.549; p = 0.033) and total mean (F(1) =4.781; p = 0.045). There was difference between the times (F(1.0) = 5.245; p = 0.037) in the sum of total SB. On the weekend average there was time*group interaction (F(1.0) = 5.416; p = 0.034). There was difference in sitting time between groups per weekday (F(1) = 6.764; p = 0.019) and in the total mean sitting time (F(1) = 6.230; p = 0.023). The intervention was effective in reducing the SB of the adolescents and brought results that contribute to the prevention of cardiovascular diseases.