These include most instances of high blood pressure, migraine and tension headaches, and peptic ulcer as well as many other problems. It is commonly estimated that 50-80% of physician visits are motivated by symptoms of stress-related illnesses. These problems can usually be prevented or treated effectively by learning to regulate the autonomic nervous system, the musculature, and the central nervous system. Autonomic Control - The autonomic system is composed of the sympathetic branch (active in response to stress), and the parasympathetic branch (active during relaxation and digestion). Self-regulation of sympathetic nervous system activity is accomplished with hand- and foot-warming and with control of palmar sweating. In a general way this may be thought of as quieting the emotions. Breathing - Everyone assumes they know how to breathe or they wouldn't be alive, but there are different breathing patterns. Those who have learned to sing or play a wind instrument have often been taught diaphragmatic breathing, but many others are uncertain about this healthy form of breathing. With diaphragmatic breathing, when a person exhales with a hand on the stomach, that hand moves toward the backbone. With inhalation, the stomach area expands like a balloon filling with air. Many people with asthma breathe exactly opposite of this, while many other people do not move the stomach at all. The first pattern is known as "reverse breathing' and the second one as "thoracic breathing." Neither of these patterns is as healthy as diaphragmatic breathing which allows the air in the bottom of the lungs to be efficiently scavenged out to be replaced by fresh air. Muscle Relaxation - Muscles are activated in response to stress as part of the fight-flight pattern. When muscles are active they use much more energy than when relaxed. When muscles are relaxed, messages are sent to the brain to the effect "everything is OK." This helps to relax both the sympathetic nervous system and the central nervous system. Muscle relaxation can be thought of as quieting the body.