Daily physical activity changes the brain activity , functional autonomy and frailty of elderly

Introduction: In Brazil, 13% of the population is composed of people with upper than 60 years, and is estimated that this number will be 29,3% in 2050. Objective: The goal of the study was to determine the profile and correlation between the variables: brain activity, functional autonomy, and frailty of the elderly with different daily physical activity. Methodology: Were selected 60 elderly inserted on an active and healthy aging program, with different levels of daily physical activity, of both sex, age upper than 60 years, and physical and cognitive functions preserved. Were evaluated frailty, functional autonomy, and daily physical activities, besides brain activity through an electroencephalogram, using as reference the international system 10/20. Results: The results showed that the more active participants got better results in functional autonomy and frailty tests, and also had recorded more brain activity in areas related to executive functions. Conclusion: The more active participants got better punctuations in functional autonomy and frailty tests, besides also got a higher brain activity. However, although the relationship found to have a background in the scientific literature, only the correlation between the frailty and functional autonomy scores was statistically significant.


Introduction
The current times are characterized by a chain of previous historical, philosophical, economic, political, and social changes that have promoted humankind's essential legacy. One of the most remarkable characteristics of this process is the continuous increase of the elderly population contingent all over the entire world (United Nations, 2017).
Besides that, another factor impacted by aging is how different brain functional areas intercommunicate efficiently (Varela, Lachaux, Rodriguez, & Martinerie, 2001). Such intercommunication has been denominated as functional brain connectivity, and recent evidence has shown a correlation between this functional connectivity and a variety of cognitive and motor functions (Solcà, Mottaz, & Guggisberg, 2016).
Thus, it is considered that the practice of any physical activity, and not just systematic physical exercises, is a way to maintain and/or increase the functionality of people during the aging process. However, it does not mean that specific planning of physical exercises is not essential for promoting health and maintaining the functional capacity of the elderly (Ferreira, Maciel, Costa, Silva, & Moreira, 2012).
Thus, the objective of this study was to determine the variables profile: brain activity, functional activity, and the elderly's cognitive performance according to different daily physical activity demands.

Methodology
The methodology employed in this study was evaluated and approved by ISECENSA's Ethics Committee for Human Research, receiving number 2.779.749. The study's universe was 2000 individuals, both genders, inserted in a program of active and healthy aging promoted by the town government.
For inclusion, the participants had to be at least 60 years old, they are inserted in some of the services offered by program of active and healthy aging and must exhibit the minimal conditions required for the practice of physical exercises, besides voluntarily sign the term of free and informed consent.
Were ineligible for the study all individuals who had diagnoses of chronic diseases that prevent them from practicing physical exercises and/or performing the proposed dynamics at the methodology, or even if they had a hearing or visual problems that would not be compensated by the use of an external device.
Of the total universe of elderly attended by the active and healthy aging program, 60 individuals were selected because they were present at the cohabitation houses when the data were recorded. So, the study sample comprised the elderly, with an age average of 72±8 Research, Society andDevelopment, v. 9, n. 9, e777997779, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i9.7779 years, being 18% male and 82% female participants. Analysis of participants' records provided by the cohabitation houses management indicated they were all from the same socioeconomic background.
Evaluation of participants' daily physical activity was made by the Baecke questionnaire modified version specifically developed by Voorrips, Ravelli, Dongelmans, Deurenberg, & Van Staveren (1991) for the elderly. This tool ranks individuals according to a score in numbers. From the test score, it is possible to classify the individuals as sedentary (score < 9), active (score between 9 and 16), or very active (score > 16) (Guedes, P. D.; Guedes, C. L. C.; Pinto, 2009).
An electroencephalogram device (Neurotec, Neuromap EQSA260 model, made in Brazil) was used to assess in real-time the brain activity of Alpha and Beta brain waves frequencies at the specific points of the cerebral cortex. The points chosen for this study were F7related to visual and auditory working memory, selective and divided attention; F8related to visual and spatial working memory, emotional processing and keeping of attention; C3 and C4related to sensory-motor functions, attention, mental processing, calm, emotion, and empathy; P3 and P4related to problem-solving, attention and association, visual processing and nonverbal association (Soutar & Longo, 2011). Besides those, points A1 and A2 were used as references and two more points as ground. All these points are by the international 10-20 system, and the adopted cares to eliminate any possible cause of interference on data collection was made according to described by Branco et al. (2020).

Verification of functional autonomy was made according to the Latin American
Development Group for Maturity (LADG) protocol for functional autonomy evaluation (Dantas & Vale, 2004). Times spent to perform the tasks planned in the LADG protocol were recorded in seconds. However, the aim of this study is to determine the variables profile: brain activity, functional activity, and cognitive performance of the elderly according to different daily physical activity demands. So, to divide the sample between participants more and less physically active in accordance with their performance in the Baecke questionnaire was established the central tendency number as the limit point to classify the participants as more or less physically active like is showing in Figure 1. Also, at Figure 1, we can notice how individuals were distributed regarding the central tendency baseline As is observed in Figure 1 makes it possible to systematically determine which participants exhibit a higher or a lower activity level according to their position either above or below the central tendency baseline. And now, it is possible to make relationships between the physical activity level and the performance at all other evaluated variables in this study. In Table 2 we can analyze the data performance according to the level of daily physical activity performed by the participants. Due to the greater number of data to be shown, Table 2 will be displayed the EEG data of Alpha frequency only.  Table 2 shows that the most active participants exhibited the best functional autonomy and frailty results. Being the most remarkable differences were found at the points P3 and P4, whose wave activity was on average 115% higher in the more active individuals than in the less active ones.
Finally, we need to know if such differences between more or less active participants could also be registered in Beta brain frequencies. The results are exhibited in Table 3. Highlights to the central tendency in accordance with the recalculated normality. Source: Authors. Table 3 shows that, only at the point F8, less active participants exhibited Beta activity 16,7% higher than the more active individuals. In all other points, the brain activity of the more active participants was higher than the less active participants' one, reaching 74% higher at point C4 and 68% at point P3.
In Figure 2 is possible to note clearly that the average range map of the brain activity was higher in the physically more active participants, which proves that a more active lifestyle promotes higher patterns of brain activity at the observed points. Research, Society andDevelopment, v. 9, n. 9, e777997779, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i9.7779 Figure 2. Maps of average brain activity amplitude at the analyzed points for the more and less active participant. Images from the software used by the EEG device used to record brain activity. Source: Authors. Finally, to try to establish a cause-and-effect relationship between habitual physical activity and the existence of frailty and functional autonomy impairment is necessary to determine the correlation coefficients of the variables, and it can be seen in Table 4.  Table 4 demonstrates the existence of a negative correlation between habitual physical activity and frailty and also between frailty and functional autonomy. In both situation that is the higher the score in the first test, the lower the score in the second. In other words, the higher is the habitual physical activity, the lower will be the participant's frailty; visual and spatial working memory, emotional processing, and maintenance to attention. On the other hand, the more active participants will probably be better in tasks that require greater demand for auditory and visual working memory, selective and divided attention (point F7).
Also, more active participants can be better in tasks which mainly relate to sensory-motor functions, attention, mental processing, calm, motion, and empathy (point C4), and also tasks related to problem-solving, attention and association, visual processing, and non-verbal association (point P3) (Soutar & Longo, 2011).

Final Considerations
Although we didn't find the elderly with upper levels of daily activity, the data profile was enough to establish marked differences between the elderly with more or less daily physical activity levels.
In general lines, the profiles of the elderly included in the sample demonstrate that the activities they used to engage at the time of the study had not been relevant for them to be classified as active according to the Baecke-Modifiedand it might be reflected in their functional autonomy scores and frailty results, once the majority of the participants exhibited some frailty.
It could also be noticed that the more active participants scored better in both functional autonomy and frailty tests, and also displayed higher brain activity in areas related to executive functions. It indicates that the elderly's adoption of a lifestyle in which includes the practice of physical activities, produces a positive impact in variables related to a better quality of life and functional autonomy.
Only one of the verified correlations was statistically significant, which didn't allow established to this sample a definitive cause-effect relationship between daily physical activity and lower levels of frailty and functional autonomy. However, our results pointed to how it is essential to motivate an active lifestyle for older people. We can suggest that other studies could be developed to verify if more significant levels of daily physical activity will promote better results in brain activity and functional variables with more significant correlations.