Wearable smart heart monitors have become popular in health care due to their small size, light weight, and accuracy. In this paper, we used such monitors to collect real-time ECG (electrocardiogram) data from high school students during school weeks. The data were transmitted to a smartphone application via Bluetooth. The raw data was then downloaded to be processed by a software tool, which generated the HRV(Heart Rate Variability) parameter RMSSD, used to analyze the subjects' stress levels. We studied and confirmed the correlation between RMSSD and stress level. Subsequently, the effect of Yoga breathing exercises on stress relief and management was investigated. The study specifically examined the impact of this practice on sleep quality and daytime stress relief, as well as its potential to improve academic performance during test-taking.