Infrasound, human health, and adaptation: an integrative overview of recondite hazards in a complex environment

Infrasound displays a special capacity to affect human health and adaptation because its frequencies and amplitudes converge with those generated by the human body. Muscle sounds and whole-body vibrations are predominately within the 5to 40-Hz range. The typical amplitudes of the oscillations are within 1–50 lm, which is equivalent to the pressures of about 1 Pa and energies in the order of 10 W m. Infrasound sources from the natural environment originate from winds, microbaroms, geomagnetic activity, and microseisms and can propagate for millions of meters. Cultural sources originate from air moving through duct systems within buildings, large machinery, and more recently, wind turbines. There are also unknown sources of infrasound. It is important to differentiate the effects of infrasound from the awareness or experience of its presence. Moderate strength correlations occur between the incidences of infrasound and reports of nausea, malaise, fatigue, aversion to the area, non-specific pain, and sleep disturbances when pressure levels exceed about 50 db for protracted periods. Experimental studies have verified these effects. Their validity is supported by convergent quantitative biophysical solutions. Because cells interact through the exchange of minute quanta of energy that corresponds with remarkably low levels of sound pressure produced by natural phenomena and wind turbines upon the body and its cavities, traditional standards for safety and quality of living might not be optimal.