Common Causes of Artifacts in HRV Readings
While some artifacts are caused by signal issues or ectopic heartbeats, there are other types of external factors that can cause artifacts in the reading.
The most common external factor would be movement artifacts. While less common with chest straps, they can still occur if the strap is not tightened properly, needs to be moistened, or needs to be replaced. With PPG sensors, armbands, or wrist-worn sensors, movement artifacts are quite a big concern. You can read more about those here: Why Watches and Wrist HR Monitors Don't Usually Work for HRV
The good news is that our app has built-in algorithms to clean obvious artifacts and provide an accurate reading: Signal Quality
We do not generally recommend that you worry about 1-2 artifacts in a 2-minute reading. We've had questions about factors that can cause artifacts, like swallowing during a reading. Swallowing can impact the reading, but usually depending on the length of the reading, it is negligible unless it happens several times. 1 swallow within a 5-minute reading will likely not impact the final results much, and you may be able to get away with it in as short as a 2-minute reading, depending on the individual. It is likely mostly due to the effect on the breathing pattern, rather than a direct "artifact" per se. You can mitigate things like this by swallowing during the pre-reading stabilization period to minimize the chance of needing swallow again during the reading.