Delete all data on Garmin Connect

You could delete your account and create a new one. You could also just delete old activities, and/or remove the device, and then adding it again.

What kind of solution is that? I have apps that I bought in the store. Should I buy them again?

Then don't delete your account. Why do you need to delete your data? 

because my son did a few runs with the watch to try it and "polluted" all my data with crazy hearth rates, records etc.

Just remove those runs. Then just use the watch for a few runs and it will fix itself.

The records must be accepted to replace the old ones. If you accepted them then just delete the records.

Then set a password for your phone and computer so only you can use. Other users should have their own accounts. 

I have been trying to remove the activities all the time on the mobile app and was not able to find the "gear wheel" that everyone is talking about. I found it on the web page and remove them. Thank you for the hints! That worked.

8548169 said:

What kind of solution is that? I have apps that I bought in the store. Should I buy them again?

Deleting the account is the fastest solution. If you need to keep the account, then use the other method - delete all activities and all daily monitoring data, though I am afraid, some of the metrics may stay preserved anyway. If you really need to delete all data, and want to keep you paid CIQ apps, contact the developer(s) and let you assure that you can move the license keys to your new account.

Yes, "other data" was issue with deleting only the single activities, but I was able to delete it with the "gear wheel" which is available also on the "Hearth Rate" widget for example. Important again is to use the web page and not the mobile app Thank you!