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Considering that changes in exercise routines might have relevance in treatment of adolescents with type 1 diabetes mellitus, we sought to assess whether spontaneous modifications to weekly exercise habits might occur in these patients and whether such variations would be accompanied by alterations in autonomic profile. In this observational study, we examined 77 patients (age 15.0 ± 0.6 years.) who in addition to a tailored optimal insulin treatment were invited to perform at least 1 h a day of moderate, aerobic exercise, as suggested by recent guidelines. Patients were studied at baseline (T0) and after 15.8 ± 0.7 months (T1). They were divided into three subgroups according to increased, unchanged and diminished total estimated weekly METs between T0 and T1. Autonomic profile was evaluated by assessing spontaneous baroreflex gain and low-frequency oscillation in arterial pressure, using spectral analysis of RR and systolic arterial pressure time series. Insulin therapy and biochemical data were similar among the 3 groups at T0 and T1, while body mass index standard deviation score was slightly reduced ( p < 0.04) and markers of autonomic performance were improved (alpha index, from 17 ± 1 to 20 ± 2 ms/mmHg, p < 0.002) in the group who increased the amount of exercise (from 1627 ± 250 to 3582 ± 448 METs min wt, p < 0.001). Furthermore, the change in total weekly METs significantly correlates with changes of key indices of autonomic regulation. The favourable autonomic effects of moderate increase in spontaneous exercise load suggest testing more formally this intervention in adolescents with type 1 diabetes. [ABSTRACT FROM AUTHOR]

Introduction: Aerobic fitness seems to provide extra protection to the cardiovascular system beyond changing the traditional risk factors, a phenomenon referred to as the risk factor gap model. Aerobic fitness may possibly lead to improved autonomic regulation. The Task Force of the American Heart Association supports a national campaign to reach specific cardiovascular health goals considering various metrics, including recommended physical activity (PA) volumes. It may be clinically relevant to assess whether autonomic remodeling occurs in those who adhere to the PA recommendations. Methods: We studied 39 healthy subjects (22 males and 17 females), subdivided into two groups, according to whether they were meeting or not meeting PA recommendations (150 min/week of moderate aerobic activity, or 75 min/week of vigorous aerobic activity, or a combination of both). For each group, we evaluated aerobic capacity (VO Peak), body composition (Fat Mass) and autonomic nervous system profile, by way of mono and bivariate spectral analysis of cardiovascular beat by beat variability. Results: Subjects following PA recommendations show higher RR period, higher RR variance, greater absolute power of the respiratory component of RR variability (HF) and higher index alpha (a measure of spontaneous baroreflex). Moreover, as expected, the group that was meeting or exceeding current PA recommendations had higher VO peak, less fat mass and greater weekly energy expenditure. Conclusion: Data show that subjects meeting current PA recommendations present a phenotype suggestive of enhanced parasympathetic drive to the SA node. This finding is compatible with the hypothesis that a more favorable autonomic profile is part of the mechanisms of the risk factor gap. [ABSTRACT FROM AUTHOR]