“More conservative guidelines advise between 500 and 1000 Hz (Riniolo and Porges, 1997; Berntson et al., 2007), which may be particularly relevant in case of lower amplitude RSA (Riniolo and Porges, 1997).”
See: https://www.frontiersin.org/articles/10.3389/fpsyg.2017.0021...
In terms of notable hardware you may want to look at this:
https://plux.info/kits/511-bitalino-mini-solo-kit-810121033....
Anyways, this series of boards (biosignalsplux) interfaces with Android/iOS/Unity/etc via hardware-specific SDKs.
Obviously Unity is for SteamVR or just Steam in general.
The boards also have official support for the package LabStreamingLayer (there are also LSL interfaces for Unity on GitHub), which is extremely useful for the kind of work you are doing, with respect to calculations, processing, and analysis.
I actually routinely work with physiological signals generated from the autonomic nervous system, and I do both processing and interfacing sides of this work. I also have an immune-mediated form of ANS failure, so I have personal relevant and translatable experience with respect to your project as a patient too.
I hope this info helps!
While developing VR experiences optimized for relaxation, we discovered different visual elements that most universally resonated across varying populations. We discovered horses resonated as an animal that represented comfort and relaxation with the majority of study participants who tried Flowly experiences. We had multiple participants who cried in relief after spending time with horses in our VR experiences. An unexpected discovery from all our testing.