RESUMO
Introduction: The autonomic nervous system is very important for controlling our body's functions, and when we are exposed to infrasound it can greatly impact this system. They control functions in our body like heart rate, blood pressure, and digestion. There are two parts: the sympathetic nervous system that gets the body ready for action, and the parasympathetic nervous system that helps the body relax and rest. Infrasound is made every day in our normal life. It can be produced by cars, trucks, airplanes, trains, large machines, air heaters and coolers, and household items such as washing machines and home theaters. The low-frequency sounds produced by these various devices can harm our bodies in many ways, particularly the autonomic nervous system that may impact the functioning of many organs and systems. However, but there are still many gaps involving this topic. Therefore, it is important to investigate how infrasound can affect the autonomic functions, objectively recording this occurrence. Heart rate variability (HRV), respiratory rate (RR), and electrodermal activity (EDA) can be used to evaluate physiological responses to stressors in real time, providing a picture of sympathetic and parasympathetic activity. Objective: To create a research protocol to study the hidden effect of infrasound on the autonomic nervous system. This protocol outlines the basics of setting up an experiment with human participants, including equipment and a step-by-step guide to prepare, apply, and analyze data. Methods: A device (speaker amplifier and low pass filter) was projected and will be made to produce infrasound (>20Hz). To collect data on adults, infrasound will be presented by the device. Before and during the infrasound presentation, we will made the following measurements: EDA; HRV; and RR. Results: To study the EDA data, the parameters for identifying the highest points in the phasic phase must be checked manually. We need to record the time the stimulus is introduced, the time it reaches its highest point, the highest point in size, and the highest point in strength in a spreadsheet. To understand the HRV and RR data, we need to carefully look at the graphs and make sure we count all the heartbeats in each situation. We need to record how long the analysis took, how many heartbeats and breaths per minute we measured, and the average breathing and heartbeat rates. We also need to measure SDRR, RMSSD, high frequency (HF), low frequency (LF), and LF/HF. We should write all this down in a spreadsheet. Subsequently, the results of all measurements will be compared between situations with and without infrasound. Conclusion: This protocol was created to study the harmful effects of infrasound on a human's autonomic nervous system. It can provide valuable information about the effect of infrasound on health, which could help in the future to prevent possible diseases.