Send us Fan Mail Kyle Baum and I unpack why recovery metrics can look perfect while your body still feels off, using HRV and the LF/HF ratio as tools rather than truth. We also dig into adrenal fatigue, low cortisol, caffeine dependence, gut health, and the hard skill every competitor needs: pulling back without losing progress. • LF/HF ratio explained as a subset of HRV and nervous system balance • why high HRV can still pair with poor training performance • blending data ...