High-intensity Interval Training does not Improve Autonomic Balance in COVID-19 Quarantines

Background: the COVID-19 pandemic has forced the establishment of mobility restrictions and confinements, the impact of which has generated a drastic decrease in the time spent practicing physical activity, which favors inactivity, sedentary lifestyle, in addition to the risk of suffering chronic noncommunicable diseases. Objective: to analyze the effects of a remotely directed 4-week high-density interval training program on heart rate variability in young adult men confined by COVID-19. Methods: a descriptive, cross-sectional and comparative study was carried out in which 8 adult men evaluated according to body mass index, a method for evaluating the intensity of physical activity carried out and the Pittsburgh Sleep Quality Index, previous intervention participated. A 30:30 high-density interval training program was developed for 4 weeks, with a frequency of 2 times a week for a period of 5 min duration. Low-frequency and high-frequency cardiac variability, the relationship between the two, and the standard deviation of the instantaneous variation of the RR intervals (SD1) were recorded. Results: significant pre and post evaluation mean changes were reported in low frequency (p = 0.009; d = 0.18), high frequency (p = 0.009; d = 0.18) and SD1 (p = 0.007; d = 0, 18), while no significant changes were reported in their relationship (p = 0.113; d = 0.16). Conclusion: 4 weeks of completion of a high-density interval training program do not generate acute adaptations on autonomic balance, the mean descriptive values reported being a possible chronic predictor of sedentary lifestyle caused by COVID-19 quarantines.