Influência do Exercício Físico Contínuo e Intermitente na Variabilidade da Frequência Cardíaca de Adolescentes com Diabetes Tipo 1

Abstract

Introduction: The Heart Rate Variability (HRV) is a modulation marker of the Autonomic Nervous System (ANS), which is controlled, mostly, by the sympathetic and parasympathetic ways. It is known that the Physical Exercise (PE) changes the Cardiac Autonomic Modulation (CAM), however, for people with Type 1 Diabetes Mellitus (T1DM) the PE demands additional cares (e.g., glycemic monitoring), what turns the response of the CAM to the PE little explored in this population. Purpose: Analyze the acute response of the CAM during Continuous Physical Exercise (CPE) and Intermittent Physical Exercise (IPE) in adolescents with T1DM. Methodology: The analytic descriptive study (quasi-experimental design) included 15 adolescents (13.2±1.6 years) with T1DM, in 5 protocol stages: I) beginning – it was accomplished the identification of the general data, Cardiorespiratory Fitness (VO2max) test and implantation of the glycemic sensor; II) after 48h of the I stage – it was accomplished CPE test (30min., with 60% of the VO2max); III) after 48h of the II stage – it was accomplished the change of the glycemic sensor implanted in the I stage; IV) after 1 month of the III stage – it was accomplished IPE test (30min., with 60% of the VO2max), being included every 5min., 10sec. of intensity ≅100% of the VO2max; and V) after 48h of the IV stage – it was removed the glycemic sensor implanted in the III stage. There was glycemic monitoring before, during and after the tests. The participants used Polar® cardiac monitor during the exercises. For analysis of the HRV, the R-R interval (R-Ri) series recorded by the monitor were corrected with the Kubios® program. The Square Root of the Average Squared Differences of Successive R-Ri (RMSSD) and the not-lineal indexes of the HRV were compared between CPE and IPE with Wilcoxon’s test. The influence was verified with Covariance Analysis. It was considered the alpha error from 5%. Results: There was no difference in the RMSSD. In the not-lineal indexes, there was difference just in the absolute median magnitude of the Approximate Entropy (ApEn) and of the Sample Entropy (SampEn). The ApEn was 1.1 and 1.0 and the SampEn was 1.4 and 0.9 to CPE and IPE, respectively. Thus, the CPE elevated the ApEn (β: 0.10; IC95%: 0.04 – 0.17; p: 0.031) and the SampEn (β: 0.52; IC95%: 0.33 – 0.71; p: 0.001) regarding the IPE. Conclusion: The acute response of the CAM was little determined by the type of PE. The difference at the ApEn and SampEn they presuppose that the CPE produce larger irregularity in the CAM. As wisely adolescents with T1DM have propensity to low cardiac resistance for PE, when considering exclusively the influence on CAM, the alteration observed at regularity (ApEn and SampEn) of the HRV (R-Ri), indicates that the CPE can be more recommended for this public (i.e., CPE overloads less the CAM than IPE in a session with the same duration).