Brazil before and during COVID-19 pandemic: Impact on the practice and habits of physical exercise.

INTRODUCTION: The goal of this study was to investigate the practice and habits of physical exercise impact due to COVID-19 social isolation before and during the outbreak in Brazil and its mains macro-regions, which have social and economic disparities. METHODS: This is an observational cross-sectional study through an online questionnaire survey. A self-administered survey (PEF-COVID19) was applied in the Brazilian general population, age ≥ 18 years. T-test for independent samples and Chi-square tests were used to compare Brazil and different macro-regions, p˂0.05. RESULTS: 1,977 participants filled the survey and 1,845 were included; 80% of the included ones were in social isolation. In general, the self-related physical exercise practice before and during the COVID-19 pandemic and exercise characteristics were highly affected by the pandemic (p˂0.05). Sedentary behavior increased significantly (14.9 vs. 29.8%) and between the active ones, the frequency of PEx per week and duration of the PEx practice decreased significantly. The motivation to exercise also changed considering performance and health before and during the pandemic, respectively (10 vs. 5.6% and 72.4 vs. 79.1%). Also, the sample started to exercise less in the night and more in the afternoon, respectively (33.7 vs. 25.3% and 19.1 vs. 31.5%). CONCLUSIONS: The COVID-19 pandemic highly influenced the physical exercise practice and habits (frequency, duration, motivation, period to exercise) in Brazil and its main macro-regions. These results can be used to create measures, as home-based exercise programs, to avoid the harm of sedentary behaviors and mental health impact during and after the pandemic.

Cortical excitability variability: Insights into biological and behavioral characteristics of healthy individuals.

Motor threshold (MT) measured by transcranial magnetic stimulation (TMS) has diagnostic utility in central nervous system disorders. Its diagnostic sensitivity may be enhanced by identification of non-pathological factors which may influence this measure. The aim of this study was to provide a description of MT variability across physiological and non-pathological behaviour characteristics in a large cohort, including hemispheric asymmetries. In a cross-sectional study, age, handedness, physical activity level, body mass index, gender/menstrual cycle phase, glycemic index and degree of stress were collected from 115 healthy participants. The resting MT of the first dorsal interosseous muscle to TMS was recorded in both hemispheres and served as an indicator of the cortical excitability level. Repeated measures ANOVAs revealed higher MT values in the non-dominant hemisphere, elderly people, stressed individuals and women with amenorrhea. Other biological and behavioral individual characteristics did not influence cortical excitability. Although the degree of interhemispheric difference varied (range: 0.2 to 4.3), depending on biological and behavioral characteristics, this variation was not significant (0.1 ≤ p ≤ 0.8). In conclusion, MT varied considerably between subjects. The difference between the hemisphere excitability that was less influenced by external factors, may be an alternative method of TMS measure to identify pathological changes of cortical excitability.