There is a significant correlation between stress and heart rate variability. 
Stress levels affect physical health, and chronic exposure to high-stress levels may increase the risk of chronic diseases.
Stress monitoring algorithms evaluate the body's perceived stress level by analyzing indicators such as heart rate variability. Higher values of stress levels indicate higher stress levels, and lower values indicate lower stress levels.
In the case of drinking, getting sick, lack of sleep, etc., the pressure may be higher than normal. Exercise may affect the measurement of stress levels.
<aside> 📌 The pressure index calculation needs more bio-data. Therefore, it takes a bit long to have the result (generally more than 1 minute).
1. Berntson, Gary & Cacioppo, John. (2007). Heart Rate Variability: Stress and Psychiatric Conditions. 10.1002/9780470987483.ch7. ↩ 2. Low, Adrian & McCraty, Rollin. (2018). Effects of Workplace Stress on Hong Kong Employees’ Heart Rate Variability. 10.13140/RG.2.2.28029.41442. ↩ 3. Rauber, Martin & Bilban, Marjan & Starc, Radovan. (2015). Occupational stress and heart rate variability. Zdravniski Vestnik. 84. 47-58.