Avaliação da modulação autonômica cardiovascular de repouso e limitação ventilatória ao exercício físico em indivíduos com diabetes mellitus tipo 2
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Date
2016-02-29Author
Tonello, Sílvia Cristina Garcia de Moura
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This thesis consisted of two studies described below. Study I aimed to evaluate whether
heart period (HP) and systolic arterial pressure (SAP) variability indexes are sensitive
enough to detect the autonomic dysfunction in patients with type 2 diabetes (DM)
without cardiovascular autonomic neuropathy (CAN) and other neuropathies. We
evaluated 34 men with DM without neuropathy manifests (GDM) and 34 apparently
healthy individuals (GC), with mean of age equal 54±6,05 e 54,50±5,96, respectively.
The protocol consisted of 15 minutes of recording the variability of HP and SAP at rest
in the supine position (REST) and after active standing (STAND). HRV and APV were
analyzed by spectral method and the indexes that estimate the baroreflex sensitivity
(BRS) through the spectral and sequence method. The high frequency band (HF, 0.15 to
0.5 Hz) of the HP was lower in the REST in GDM than in the control group, while in
the STAND there was no difference between groups. The band of low frequency (LF,
0.04 to 0.15 Hz) in systolic arterial pressure (SAP) was similar in REST and increased
during STAND in both groups. BRS estimated in the HF band and indexes of baroreflex
sequence method was lower in GDM than in GC in supine position and they decreased
during STAND in both groups. Thus, we concluded that the vascular sympathetic
control and baroreflex response after active postural change are preserved in the
population studied, but the vagal control of heart rate and cardiac baroreflex presented
reduced in GDM, showing that the indexes of cardiovascular variability are sensitive
enough to typify the early, peculiar, signs of autonomic dysfunction in type-2 DM
patients well before CAN becomes manifest. Following evaluating also individuals with
type 2 diabetes mellitus (DM) without neuropathy manifests, the Study II aimed to
evaluating the EFL using the expiratory flow-volume loop (EFVL) during two
intensities of exercise, and additionally assess if it is related to the reduction of aerobic
capacity in DM. Forty men were evaluated and equally divided in two groups matched
for age, i.e. subjects with DM (GDM) and control group (GC). Initially, the volunteers
performed cardiopulmonary exercise testing (CPET). After this, they underwent two
constant load tests (CWETs) at moderate and high intensity exercise in order to evaluate
and classify the EFL by EFVL method, which consisted of plotting the EFVL within the
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maximal volume flow loop (MAFV). Statistical tests were applied and p< 0.05 was
considered as significant. The GDM presented decreased of aerobic capacity when
compared to GC, however GDM showed similar responses to GC for the LFE in
moderate intensity, despite a greater number of individuals with severe LFE in high
intensity of exercise. In addition, it was not found the relationship between the LFE and
aerobic capacity of GDM, that is, the low aerobic capacity of GDM is not related LFE.
Thus, the studies presented in this thesis brought important contributions to the
improvement in the treatment of individuals with DM due to findings related to vagal
commitment and possible pulmonary subclinical impairment and circulatory
adjustments during the exercise, providing assistance in exercise prescription in the
cardiopulmonary rehabilitation for this population.