Any sudden movements or reactions in our body are mostly due to the sound we hear near by. They create panic and level of unrest in our nervous system. Even if it is small they are processing in our brain in back end. Sometimes loud sounds impact our brain negatively. Anxiety, fear, alertness are results of the sound pollution.
Living in cities may be even harder as number of sounds such as traffic, construction and verbal sounds are processed in the brain. By using foam based ear plugs during sleep and work the quality increases. This is my personal experience.
If we further deeper in our biology, There are many invisible natural forces acting on us which our body has to fight unconsciously like gravity, extreme light, extreme sound, rotation of earth.
The only thing we can control is sound from entering our brain and explore other dimensions of our body and think clearly.