Considering the increase in the age of the population and consequent increase in cardiovascular risk, in addition to the increasingly sedentary changes in the lifestyle of the population, our findings showed that the less active group had higher SBP and DBP values compared to the active group. The most active group showed higher VAR RR values and the IP HF band in relation to the less active group, in addition to a lower sympathovagal balance, indicating lower cardiac sympathetic modulation.
The habitual physical activity questionnaire (PAQ), used in this study, allowed us to verify the energy expenditure dispensed in daily activities during the 12-month period. Through this questionnaire, we divided the participants of this study into three groups to analyze the influence of physical activity on quality of life and health of people over 60 years of age (9). The least active group presented the lowest value of energy expenditure, being considered as a sedentary group. It is worth noting that in the Western world, sedentary lifestyle, as a risk factor for health, is only surpassed by tobacco consumption and is highly representative (14, 15). The global challenge of physical inactivity is further amplified by the risk it carries. We have observed in some studies enough evidence that 6-10% of all deaths from noncommunicable diseases worldwide can be attributed to physical inactivity, and this percentage is even higher for specific diseases (eg. 30% for the ischemic heart disease). In 2007, 5.3 to 5.7 million of deaths worldwide from noncommunicable diseases could have been avoided if, in theory, people who were inactive were sufficiently active (16).
In addition, some serious health problems are associated with obesity, including type II Diabetes and cardiovascular disease. White adipose tissue is not only a place for energy storage, but it is also an active endocrine organ that secretes more than 50 cytokines/chemokines and bioactive mediators called adipocytokines that are involved in lipid metabolism, insulin sensitivity, immunity, angiogenesis and inflammation (17).
According to Santanasto (2017) with aging there is a reduction in muscle mass and an increase in the accumulation of body fat, which may be related to food and cultural habits (18). The least active group presented higher values of SBP and DBP compared to the active group. In this sense, it is worth remembering that CVD mortality increases considerably with elevated blood pressure.
Regarding the results obtained from the lipid profile, the less active group presented a high level of triglycerides and a reduction in the level of HDL, if changes in LDL and VLDL in relation to the other groups. Vellosa et al. (2013) observed that the decrease in the plasma concentration of HDL is strongly related to the development of endothelial dysfunction and, consequently, to CAD (19).
Furthermore, some studies have shown that heart rate variability (HRV) is reduced in stress conditions and in many chronic diseases, and may even predict the development and prognosis of some diseases (6). In a recent study of our group, we showed that sedentary women presented higher heart rate, lower variance of RR interval and RMSSD and higher cardiac sympathovagal balance (LF/HF) both at rest and in response to the mental stress test in comparison to physically active women (20). In the HRV spectral analysis, the less active group showed lower IP VAR and IP HF band in relation to the active group, besides a higher sympathovagal balance, indicating a higher cardiac sympathetic modulation.
According to our findings, some authors mention that there are losses in HRV with aging and a less active life (21, 22). It is important to emphasize that the reduction in HRV is related to a decrease in vagal activity over the sinus node and may be associated with other risk factors and increased sympathetic activity related to high plasma noradrenaline concentration in individuals over 65 years (23).
Studies show that higher HRV values indicate better adaptation and control of the sympathetic and parasympathetic nervous system, and active individuals have a better index in the time and frequency domain due to the increase in vagal tone caused by the practice of physical activity (24). Recent study showed that sedentary offspring of hypertensives, in contrast with the strength-trained group, presented impairment of total variance of RR interval, as well as an increase in cardiac sympathovagal balance (25).
Our results corroborate these findings, since the active group showed higher VAR RR and AF component (m²), as well as a better sympathovagal balance. In addition, studies have demonstrated that cardiovascular autonomic dysfunction, evidenced by a reduction in HRV, is associated with higher levels of inflammatory mediators such as TNF-α and IL-6 (26). In addition, a study of our group showed that cardiovascular autonomic dysfunction precedes metabolic dysfunction in male mice submitted to chronic consumption of fructose (27). Finally, studies show that the vagus nerve can modulate the inflammatory response and oxidative stress in some pathophysiological situations (28, 29).
In this sense, the results of the present study suggest that the best cardiac autonomic modulation observed in the active elderly group may be associated with the reduction of inflammatory mediators and oxidative stress, which together could be related to the reduction of cardiovascular and metabolic risk in this phase of life.
In fact, regardless of age, the practice of physical activity seems to be beneficial and helps increase the standard curve of physiological aging (18). In addition, changes in lifestyle are recommended in the primary prevention of hypertension, and in individuals with borderline BP. These changes may reduce BP as well as cardiovascular mortality. The main non-medicinal recommendations for the primary prevention of hypertension are: healthy eating, controlled consumption of sodium and alcohol, potassium intake, sedentary lifestyle and smoking (11).