The Sub-THz Emission of the Human Body Under Physiological Stress

• Published in: IEEE transactions on terahertz science and technology Vol. 11; no. 4; pp. 381 - 388
• Main Authors: Baksheeva, Ksenia A., Ozhegov, Roman V., Goltsman, Gregory N., Kinev, Nickolay V., Koshelets, Valery P., Kochnev, Anna, Betzalel, Noa, Puzenko, Alexander, Ben Ishai, Paul, Feldman, Yuri
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.07.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Black body radiation; Embedded structures; Emission spectra; Frequency measurement; Frequency spectrum; Galvanic skin response; Heart rate; Human performance; human skin emission; Metamaterials; Protocols; Psychological stress; Radiometry; Remote monitoring; Skin; Stress; Stress (physiology); Stress measurement; sub-THz; sweat ducts; Temperature measurement; Terahertz frequencies
• ISSN: 2156-342X; 2156-3446
• DOI: 10.1109/TTHZ.2021.3066099

We present evidence that in the sub-THz frequency band, human skin can be considered as an electromagnetic bio-metamaterial in which its natural emission is a product of skin tissue geometry and embedded structures. Radiometry was performed on 32 human subjects from 480 to 700 GHz. Concurrently, the subjects were exposed to stress, while heart pulse rate (PS) and galvanic skin response (GSR) were also measured. The results are substantially different from the expected blackbody radiation signal of the skin surface. PS and GSR correlate to the emissivity. Using a simulation model for the skin, we find that the sweat duct is a critical element. The simulated frequency spectra qualitatively match the measured emission spectra and show that our sub-THz emission is modulated by our level of mental stress. This opens avenues for the remote monitoring of the human state.