Samsung smart watches:
If you're using a Samsung smart watch with the "Samsung Health" app, you can easily grab your heartrate data. In the app press the three dots in the right corner and then press
Settings. Scroll down to the privacy section and press
Download personal data. Your phone will now start downloading all your health metrics. When finished, return back to this page, press the "Browse" button and browse to your downloads folder. Here you'll find a new folder called
Samsung health. Inside of this folder, you'll find another folder with your name, and in this folder you'll find a bunch of files. Select the one beginning with
com.samsung.shealth.tracker.heart_rate. Now you're set, enjoy your visualizations!