The relationship between sound waves and human physiology is intricate. Immediately upon hearing a loud noise, a neurohormonal cascade of events is triggered inside of our bodies, and our stress hormone levels rise.
Evolutionarily, this is quite advantageous. If the sound was caused by lightning hitting the tree next to you, those stress hormones pumping through your body might save your life.
But these fight-or-flight systems can be overstimulated. Living next to a noisy highway, for example, could keep stress hormones chronically elevated.
A recent review published in the journal Redox Biology showed a definite link between so-called “noise pollution” and the generation of molecules called reactive oxygen species (ROS) in our bodies. ROS can act on the thin lining of blood vessels by depleting nitric oxide, which keeps the vessels healthy by limiting constriction and preventing immune cells from aggregating along vessel walls. A lack of nitric oxide can increase a person's risk of high blood pressure, diabetes, and arterial plaque formation — all of which can contribute to cardiovascular and metabolic disease.
This research suggests that limiting exposure to noise pollution may be important in human health and longevity.