This device measures oxygen saturation of your blood (SpO₂) and your heart rate. Normally a pulse oximeter is used by people who have difficulties breathing so that they can monitor their oxygen levels. Chronic hypoxia can cause serious health issues. However, it can also be used to measure intermittent hypoxia. A pulse oximeter measures your heart rate so that you can monitor how your resting heart rate drops as you become fitter and healthier over time.
HRV Chest Strap and App
These will help you monitor your Heart Rate Variability (HRV). Your HRV indicates how adaptive and resilient your body is to stress. An app like SweetBeat HRV will give you a score for your HRV. In this particular app, a score between 70-100 is a sign of a good heart health, whereas a score of 40 or lower is a sign that you are struggling with stress and your heart health has room for improvement. Your score should improve gradually over time as you practice the Therapeutic Breath techniques.
Simple, but effective: mala beads can be used to help count the number of repetitions for certain breathing exercises.