Retching, commonly referred to as dry heaving, is the body’s involuntary attempt to vomit without the actual expulsion of stomach contents. This reflex involves spasmodic muscle contractions that simulate the act of vomiting but result only in the movement of air or mucus. Retching is a non-productive effort, meaning no gastric material is forcefully ejected from the mouth. The experience is often preceded by nausea, the unpleasant feeling of an impending need to vomit.
The Physical Mechanism of Retching
The entire reflex is centrally controlled by the vomiting center, a network of neurons located in the medulla oblongata of the brainstem. This center integrates various signals from the inner ear, the digestive tract, and the chemoreceptor trigger zone in the brain. When activated, the vomiting center initiates a coordinated sequence of muscular events aimed at emptying the stomach.
Retching begins with rhythmic contractions of the abdominal muscles and the diaphragm against a closed glottis, which is the space between the vocal cords. The diaphragm contracts downward while the abdominal muscles contract inward, creating pressure changes between the abdominal and thoracic cavities. This pressure difference forces the stomach contents upward into the esophagus, but the closed glottis and upper esophageal sphincter prevent them from exiting the mouth. The characteristic heaving motion results from this alternating elevation and descent, occurring about once per second.
Immediate Techniques to Halt the Reflex
Interrupting the retching reflex requires engaging the parasympathetic nervous system or physically distracting the body. Controlled, deep diaphragmatic breathing is an effective method because it directly opposes the spasmodic, shallow breathing of the reflex. To perform this, inhale slowly through the nose, allowing the abdomen to expand, hold the breath for a few seconds, and then exhale slowly through the mouth, making a gentle “whoosh” sound.
Focusing on a specific breathing pattern, such as the 4-7-8 technique—inhaling for four counts, holding for seven, and exhaling for eight—can serve as a mental distraction to override the neurological loop.
Posture adjustments can help minimize the physical strain and esophageal reflux that may trigger further retching. Sitting upright or slightly leaning forward keeps the stomach contents lower and reduces the pressure on the lower esophageal sphincter.
Sensory input can be used to redirect the brain’s focus away from the distress signal. Sucking on ice chips or slowly sipping a cold, clear liquid, like ginger ale or peppermint tea, provides a mild counter-stimulus to the mouth and throat. Some people find relief by applying pressure to the P6 (Neiguan) acupressure point on the inner wrist, which has been associated with managing nausea.
Identifying Underlying Triggers and When to Seek Medical Care
Retching that occurs frequently or chronically often points to an underlying condition that requires proper diagnosis and management. Gastroesophageal reflux disease (GERD) is a common trigger, as stomach acid backing up into the esophagus can irritate the lining and provoke the reflex. Other causes include post-viral syndromes, certain medications that irritate the stomach lining, and chronic anxiety or emotional stress, which can stimulate the central nervous system’s vomiting center.
Conditions like Cyclic Vomiting Syndrome (CVS) involve recurring, intense episodes of retching and vomiting that can last for hours or days. Chronic motion sickness, low blood sugar, excessive alcohol consumption, and intense exercise can also be acute triggers. Identifying and avoiding these specific triggers is the primary long-term strategy for prevention.
It is important to consult a healthcare professional if retching is persistent, meaning it lasts for more than 24 to 48 hours, or if it occurs without a clear, temporary cause. Immediate medical attention is necessary if retching is accompanied by signs of severe dehydration.
Signs of severe dehydration include:
- Little to no urination
- Lightheadedness
- Extreme thirst
Other serious symptoms that warrant an immediate visit include severe abdominal or chest pain, high fever, or any sign of blood in the vomit.