The world is full of different sounds, but only its small part is available for the human ear. It is known, that human body can generate mechanical vibrations of very low frequency (so-called infrasonic waves). Such low-frequency vibrations are produced by physiological processes: heart beating, respiratory movements, blood flow in blood vessels, and other processes. The frequencies of these vibrations are between 0,01-103 hz. Different organs of the human body have different own resonance frequencies. The heart resonance frequency is ~ 1 hz. The brain has a resonance frequency of ~ 10 hz, blood circulatory system – 0,05÷0,3 hz.
MEPhI Department №37 students Alexandra Smirnova and Olga Molchanova (research supervisor – Dr. Phys.-Math.Sci., Professor E.A.Protasov) with the help of highly sensitive laser device registered infrasonic vibrations in human body and researched effects, connected with appearing of infrasonic vibrations of different frequencies. “We tried to find out factors, influencing amplitude-frequency characteristics of such vibrations,” said Olga Molchanova.
While conducting the research it was discovered that the observed vibrations are connected with cardiovascular system, which has its own proper movements, going on simultaneously with the work of the cardiac muscle. Also 3 types of infrasonic vibrations were registered. Waves of the first type are connected with the heartbeat (pulse), of the second type – with the human respiratory rhythm, the third type waves are called Traube-Hering waves, which are often observed in the state of emotional tension. Thus, it will be possible to judge the human emotional state at the concrete moment of time by amplitude frequency response of these waves.
At the stemming of the blood flow along vessels with the help of tourniquet application to the arm wrist the effect of tissue clarification is observed (the intensity of the laser radiation through tissues has grown), which is connected with the stop of the blood inflow into vessels. This effect is observed due to the lowering of the tissue enrichment by oxygen, which swallows radiation in the nearest infrared region. Under the breath holding the effect, opposite to the “clarification effect”, was observed, i.e. the intensity of the laser radiation through tissues lowered. It might be connected with the fact that during the breath hold blood is saturated with hemoglobin, which leads to the increase of laser radiation swallowing and the decrease of the signal.
Methods in the basis of registration of human radiation are important for medical diagnostics because they are non-invasive. The tasks of change and research of proper infrasonic fields can be of interest.
