摘要：The aim of this study was to assess the autonomic response on different micro-cycles of training in healthy swimmers, and their relationship with physical fitness indicators. Seven swimmers with national indices underwent three training micro-cycles during the winter. Five minutes of HRV was recorded before the first daily training session. An ANOVA was applied to observe the differences between micro-cycles, and the correlation between fitness and HRV was tested. The aerobic power micro-cycle presented indicators of increased sympathetic activity compared to other micro-cycles. An absolute increase in vagal activity was observed in lactic anaerobic cycle, while the alactic anaerobic cycle showed a decrease in vagal activity compared to lactic. As to physical fitness indicators, body fat and VO_2 max impacted positively on sympathetic-vagal control. The intensity of swimming training micro-cycles autonomic control is minimally noticeable after a recovery period with an apparent relationship between aerobic power training and sympathetic activity. The vagal activity is more evident during lactic anaerobic training. The results confirm that the physical fitness indicators impact the sympathetic-vagal control, especially the sympathetic activity.
