Hey there,
HRV data is available in the standardized data models through:
Activity payloads - with hrv_samples_rmssd and hrv_samples_sdnn arrays
Sleep payloads - with detailed HRV measurements during sleep
Daily payloads - with 24-hour HRV summaries
**Data delivery frequency: ** Data is pushed automatically to your configured destination (e.g., webhook) when new data syncs from the user's wearable. For event-driven integrations, this happens immediately; for polled integrations, Terra checks every 5 minutes.
HRV measurement types:
RMSSD (Root Mean Square of Successive Differences) - most commonly measured, can be sampled in as little as 30 seconds to 5 minutes
SDNN (Standard Deviation of N-N intervals) - typically requires longer sampling (5 minutes to 24 hours)
**Regarding: Streaming API (Real-Time Data):
**
The Streaming API enables real-time data streaming on a ~per second basis from BLE and ANT+ devices. You can stream metrics like heart rate as most devices focus on continuous heart rate monitoring rather than HRV calculations.
Hope this helps!