Kardia is a mobile app that offers a simple deep breathing exercise to help relieve stress, anxiety, and improve focus. The app guides users through the exercise with sounds and the movement of a sphere, allowing them to feel their body and mind relax. It also helps regulate heart rate in sync with the breath. The exercise is suitable for people of all ages, including children, and can be completed in just a few minutes.

Users have praised the app for its effectiveness and simplicity. Many have found it to be a useful tool for practicing cardiac coherence, a state where heart rate variability increases and becomes regular through paced breathing. This state has been scientifically proven to have positive effects on stress, anxiety, blood pressure, depression, and sleep. The app also offers additional features such as customizable breathing rates, inhalation/exhalation ratios, and exercise durations.

Kardia can be used for various purposes, including stress relief, calming anxiety attacks, improving concentration, aiding sleep, relaxation, yogic breathing, meditation, and sophrology exercises. The app can be used without constantly looking at the screen, thanks to guiding sounds and vibrations. It is also ad-free and offers a free trial period for exclusive features such as relaxing sounds, visual cues, customized vibrations, and more. Users can unlock all features with a single in-app purchase.

Overall, Kardia is a user-friendly app that provides a convenient and effective way to practice deep breathing exercises for relaxation and overall well-being. With its customizable features and scientific backing, it offers a personalized experience for users to find the breathing rate that works best for them.