Panic attacks may seem sudden and unexpected. In fact, physiological instability is detectable for at least an hour before a patient is aware that the panic attack will happen.
Panic attack sufferers may be susceptible to a mounting accumulation of subtle physiological instabilities, though they would be completely unaware of those changes.
Alicia E. Meuret, lead researcher and a psychologist at Southern Methodist University in Dallas, called the results amazing. She noted that those physiological instabilities were not present during times a patient was nearing a panic attack.
The study was based on monitoring 43 panic disorder patients 24-hours a day while they went about their daily activities on two separate occasions. Researchers captured 1,960 hours, including 13 panic attacks, through the monitoring. The monitoring captured changes in respiration, heart rate, cardiac functions and evidence of sweating through a series of sensors and electrodes, as well as a small wrist pack with a panic button that patients pushed if they had a panic attack.
In addition to showing the physiological instabilities despite a patient's lack of awareness, the monitoring showed that patients were chronically hyperventilating, likely as a result of abnormally low carbon dioxide levels.
Researchers found that these carbon dioxide levels rose shortly before a panic attack occurred. As those levels increased, patients reported anxiety, chest pain and fear of dying. Though changes were detected, investigators are not yet sure what prompted the physiological changes.
However, the research may help explain why panic disorder medication aimed at normalizing breathing is effective. The drugs generally buffer arousal, ensuring it remains low and level, which can prevent panic attacks.
Meuret noted that the research could be significant because it could mean discovering how to predict other diseases with seemingly "out-of-the-blue" onsets such as strokes, seizures and manic episodes. Finding a way to predict when those events might occur could ultimately allow doctors to work to prevent them.
The research was published in journal Biological Psychiatry.