This app uses the camera to measure your heart rate and calculates your heart rate variability.

The HRV is an index of activity of the autonomic (vegetative) nervous system.

The higher your HRV, the higher the balloon will fly (biofeedback).

Focus on your heart (and breathing) and get an idea what helps you to calm down (what makes the balloon rise).

The area around the camera will get warm during measurements. That's normal.

This is no medical app!
The measurement highly depends on correct usage (your finger should be placed so that the camera can clearly see your blood flow and you should limit moving the measured finger as good as you can).

Measuring the HRV right after physical activity is not the purpose, as the HRV has a different meaning for higher heart rates.

The HRV value this app uses is RMSSD.

If you're reading this, release your shoulders from your ears, unclench your jaw and remove your tongue from the roof of your mouth. We physically tend to hold on to stress in least noticeable ways. Relax.