Infrasound refers to extremely low-frequency sound waves, below 20 Hertz (Hz), which are generally beyond the range of human hearing. These vibrations can arise from natural events such as storms, as well as human-made sources like traffic and industrial equipment. In the animal world, some species rely on infrasound to communicate, while others actively avoid it. When scientists examined whether people can perceive infrasound, they found that we are not consciously aware of it. However, our bodies still react. Exposure has been associated with increased irritability and higher levels of cortisol, a hormone linked to stress. "Infrasound is pervasive in everyday environments, appearing near ventilation systems, traffic, and industrial machinery," said Prof Rodney Schmaltz of MacEwan University, senior author of the article in Frontiers in Behavioral Neuroscience . "Many people are exposed to it without knowing it.…