No worries. Wrist measurements are noisy and difficult, but there is a great deal of info to be extracted from heart rate data. Lots of teams, including Apple

No worries. Wrist measurements are noisy and difficult, but there is a great deal of info to be extracted from heart rate data. Lots of teams, including Apple, are working to figure it out. The better the extraction of heart rate from the data, the more that can be done done with it. For example, there are groups using heart rate variability (HRV) characteristics to predict neonatal sepsis, a leading cause of death in infants. https://pubmed.ncbi.nlm.nih.gov/31295130/ https://pubmed.ncbi.nlm.nih.gov/31295130/ https://pubmed.ncbi.nlm.nih.gov/11134441/ https://pubmed.ncbi.nlm.nih.gov/11134441/ That work is not with a watch of course, but it is extending the understanding of the relationships of HRV to other physiological issues. Good stuff.