Hey Ange
All of those things do work. I have the Bioforce HRV. What I like about it is that if some of the things are off that you mentioned, it will show up in the numbers. If I don’t get good quality sleep or there is extra stress with family, my numbers will always be off. The other thing I like about bioforce vs. ithlete is that the bioforce program will also give a readiness scale, so you have an idea of exactly how hard you can push that day. Of course, things may change during the workout. I don’t think HRV is necessary for everyone, but I do think it is a good product to help people test their readiness. It should not supersede any of the things you mentioned, but should be used in conjunction with them.