Heart Rate Variability of Premature Newborn

To analyze the effects of two CPAP methods on the HRV of PTNBs during their routine routine in the HCUFU neonatal ICU. This is a randomized clinical trial, with controlled groups and cross over with healthy term newborns (RNT) as a control group admitted to the HC-UFU rooming-in and premature newborns (PTRN), between 28 and 32 weeks pregnant women with nasal CPAP group admitted to the neonatal ICU of the same hospital. The HRV recorded by the POLAR® RS800cx cardiac monitor will be analyzed, with a sampling rate of 1000 Hz. The main question\[s\] it aims to answer are: * Is there a difference in heart rate variability between newborns using conventional nasal CPAP and nasal bubble CPAP? * Is it possible to conclude that one of the methods has a greater sympathetic or parasympathetic tone compared to the other? Premature participants will be in the incubators in a supine position with 30 minutes rest after the last handling. Each data collection will last 60 minutes and will be carried out three times a day in the morning, afternoon and night shifts, for each 1-hour collection, HRV will be analyzed in 12 5-minute intervals, establishing an average for each variable of the data. HRV during a 1-hour period. The researchers will compare the conventional CPAP and bubble CPAP group according to randomization. * In the control group, data collection will be carried out in the Rooming Room in a single reference collection lasting 20 minutes, and analyzed in 4 5-minute intervals. * The participant selected for conventional CPAP will receive conventional CPAP for 24 hours, then receive bubble CPAP for 24 hours the following day. The opposite will be done for the participant drawn for CPAP bubbles. The comparison between the conventional CPAP and bubble CPAP groups will occur to find out whether it is possible to identify the type of non-invasive ventilation that allows an increase in HRV and parasympathetic tone variables, as well as a reduction in sympathetic tone variables and the stress index of premature babies.