150
after ET [ 46 ]. Moreover, correlations were observed between autonomic improve-
ments (reduction of sympathetic activity and increased in vagal activity) and brady-
cardic response, which suggests that improvement in BrS would occur due to
improvement of autonomic control [ 46 ].
6.2 Diabetes
Diabetes is related to several cardiovascular risk factors, such as: dyslipidemia, ath-
erosclerosis, diabetic autonomic neuropathy, inflammation, increased ROS forma-
tion, impairment of flow-mediated vasodilation, among others [ 49 , 50 ].
When together with cardiovascular disease, as MI, additional complications areobserved in diabetic rats, such as augmented autonomic impairment represented by
reduced BrS and vagal tone. Moreover, cardiac autonomic dysfunction was associ-
ated with impaired hemodynamic function and cardiorespiratory capacity, as well
as increased mortality rate [ 51 ]. On the other hand, when diabetic and infarcted rats
underwent ET, animals showed increased mRNA and protein expression of vascular
endothelial growth factor (VEGF), as well as regularization in the elements involved
in calcium handling, to quote: SERCA2, Na+–Ca2+ exchanger, SERCA2/
phospholamban ratio and phosphor-thr17-phospholamban. In addition, authors
observed normalization in the hemodynamic function and in regional blood flow, as
well as improvement on autonomic function [ 51 ]. Lastly, ET collaborates to reduced
mortality rate in diabetic infarcted rats [ 52 ].
6.3 Obesity
Obesity is another pathology associated with cardiovascular abnormalities. Besides
its effects on metabolic profile, obesity also affects heart structure and function [ 53 ].
Moreover, adipose tissue is strongly associated with elevated inflammatory and
ROS markers, both elements that collaborate to elevated cardiovascular disease and
development of MI [ 54 ]. In this sense, in a study designed to identify the effects of
ET on obese MI rats, authors observed that, after exercise, the heart of the animals
showed decreased ROS protein expression and activity, as well as increased antioxi-
dant activity. These alterations were associated with increased survival rate [ 54 ].
7 Conclusions
Corroborating international guidelines for cardiac rehabilitation, experimental stud-
ies confirm that exercise is of great importance to optimize cardiovascular recovery
after MI, and shed light on the mechanisms that may respond for cardiac alterations
I.C. Moraes-Silva et al.