I want to trigger a HRV-measurement on my Apple Watch 4 programmatically. Is there a way to start the breath-app from my own app in background to trigger the HRV measurement? Or is it possible to trigger a HRV-measurement directly? 

If not is there even an alternative to measure stress in nearly realtime programmatically on my Apple Watch 4 ?

Please provide me some Code examples if you know an answer.

Thank you in advance!