Modulação autonômica cardíaca no repouso e na recuperação após esforço físico máximo de jovens saudáveis com diferentes níveis e tipos de atividade física

Abstract

Factors influencing cardiac autonomic modulation are not well known yet, and the results regarding the influence of regular physical training on such modulation are controversial. Considering this context, we propose the development of two studies whose results might contribute with additional information in regards to those factors. The first studied Influence of aerobic and resistance training on cardiac vagal modulation during rest and recovery aimed at investigating the influence of both aerobic and resistance training on cardiac autonomic modulation, observing the behavior of both the Heart Rate Variability (HRV) and the Heart Rate Recovery (HRR) indices. Forty-seven healthy young men with aerobic fitness levels which were statistically similar and close to the population average, were divided into three groups according to the level and type of physical activity identified through the Raw Sport Score (RSS) of Baecke questionnaire: 18 sedentary subjects (SE) being 21.8±1.5 years old; 15 resistance trained subjects (RT) with mean age of 21.2±2.3 years; and 14 aerobically trained subjects (AT), with mean age of 23.3±4.1 years. The NN intervals records were obtained during rest in the supine position for 15 minutes, along all the period in which the maximum cardiopulmonary test in cycle ergometer was carried out, and for 5 minutes of recovery after the latter test. Data collected allowed the HRV analysis in the domains of both time (SDNN, RMSSD and pNN50 indices) and frequency, through the low frequency bands (LF), the high frequency ones (HF), and through the HF/(LF+HF) ratio; besides the SD1 index of Poincaré plot. The main results with p<0.05 showed that, regardless the type of physical training performed, active volunteers presented better HRR results, obtained through D60s (p=0.002) and ô (p=0.046). However, they did not present differences in the HRV indices during rest. Only AT presented better vagal reactivation during the recovery period, assessed through RMSSD30 (p<0.05). No correlation was found between the HRV indices during rest and the HRR ones. In summary, we found that, in the beginning of the recovery period subsequent to maximum physical effort, subjects involved in both aerobic and resistance training activities presented better HRR than sedentary ones. Only aerobically trained subjects presented better vagal reactivation assessed through RMSSD30. Besides, neither the Heart rate (HR) decrease during recovery nor RMSSD30 seem to be related to the HRV vagal indices during rest. The second study Influence of labor and leisure activities level on rest and recovery autonomic cardiac behavior of healthy young men aimed at investigating the influence of the level of labor and leisure activities on rest and recovery cardiac autonomic modulation of youngsters who, although did not engage in systematized physical training activities, presented different levels of labor and leisure activities. Twenty men were divided into two groups according to Total Score Baecke (TSB): 10 less active subjects, presenting an average age of 22.8±1.9 years, and 10 more active subjects, with ages around 22.3±2.2 years. Volunteers went through the same tests and recording procedures described above and data were submitted to the same HRV and HRR indices analyses performed in the first study. The main finding shows there were no significant differences between the two groups in the HRV and HRR indices in the domains of time and frequency. In summary, it is claimed that labor and leisure activities alone seem not to have caused significant effects to the autonomic cardiac modulation of the young men studied. Hence, the need for regular physical training is reinforced in order to promote cardiac autonomic adaptations.