Biofeedback takes advantage of electronic instruments or other techniques to monitor and change subconscious activities, many of which are regulated by the ANS. Skin temperature, heart rate, and brain waves are monitored electronically. By watching the monitor and using biofeedback techniques, a person can learn how consciously to reduce his heart rate and blood pressure and regulate blood flow in the limbs. For example, it has been claimed that people can prevent the onset of migraine headaches or reduce their intensity by learning to dilate blood vessels in the skin of their arms and hands. Increased blood vessel dilation increases skin temperature, which is correlated with a decrease in the severity of the migraine.

Some people use biofeedback methods to relax by learning to reduce the heart rate or change the pattern of brain waves. The severity of stomach ulcers, high blood pressure, anxiety, and depression may be reduced by using such biofeedback techniques.

Meditation is another technique that influences autonomic functions. Although numerous claims about the value of meditation include improving one's spiritual well being, consciousness, and holistic view of the universe, it has been established that meditation does influence autonomic functions. Meditation techniques are useful in some people in reducing heart rate, blood pressure, severity of ulcers, and other symptoms that are frequently associated with stress.

The fight or flight response can occur when an individual is subjected to severe stress such as a threatening situation or a repugnant event. The response may be one of confrontation or one of avoidance such as running. The response involves all parts of the nervous system, as well as the endocrine system, and can be consciously or unconsciously mediated. The autonomic part of the fight-or-flight response results in a general increase in sympathetic activity, including heart rate, blood pressure, sweating, muscular strength, and other responses, that prepare the individual for physical active. The fight-or-flight response is adaptive because it enables the individual to resist or move away from a threatening situation.