Palo Alto Health Sciences has raised $1.97 million in the second tranche of a $5 million round. Aphelion Capital led the financing with participation from other angel investors. To date, the company has raised $7.5 million for its mobile-enabled breathing system for people with panic disorder.

Called the Freespira Breathing System, the FDA-cleared solution is based on research from Stanford University and Boston University in the mid 2000s, which found that people who have panic disorder are chronically over-breathing, not just when they have a panic attack, but all the time.

“People who have this condition, panic disorder, have a physiologic issue,” Palo Alto Health Sciences CEO Debra Reisenthel told MobiHealthNews. “They use this technology and protocol to test whether or not, if you train people to breathe in a way that is functional, it can help people to breath with a normalized respiratory rate and also increase their level of carbon dioxide. These patients can actually stop having panic attacks and can stop having these symptoms of panic.”

Freespira Breathing System includes a small sensor and a tablet app to measure a user’s breathing rate as well as the amount of carbon dioxide in each exhale. The system is delivered through a four-week program, consisting of audio and visual-led breathing exercises. Users complete two 17-minute sessions every day, and the program costs $499 for the one month of treatment.

The company is marketing Freespira to patients through their therapist or counselor, but patients can also access Freespira directly without a therapist or clinician.