"Research has long substantiated the harmful effects low frequency noise can have on people. Symptoms include aggravation, decreased concentration, premature exhaustion, elevated blood pressure, increased heart rate, insomnia, migraines, anxiety, frustration, sleep disruption, anger, contempt and many others."
Here's an article on Low Frequency Intrusion:
http://www.lowfrequencyintrusion.com/?p=about
"Research has long substantiated the harmful effects low frequency noise can have on people. Symptoms include aggravation, decreased concentration, premature exhaustion, elevated blood pressure, increased heart rate, insomnia, migraines, anxiety, frustration, sleep disruption, anger, contempt and many others."