HRV is measured first thing on waking, before coffee, in the same body position every day. The trend matters more than the daily number — a single low day means little; three or four in a row means something is going on. Drivers of suppressed HRV: poor sleep, alcohol, recent hard training, illness coming on, life stress. Cyclists who track HRV consistently spot the early signs of overreaching about a week before they would otherwise feel it in the legs. Tools that work for daily readings: Whoop, Garmin (with Body Battery), Oura, HRV4Training. The mistake to avoid: training off a single morning's reading. The 7-day rolling average is what matters. Anthony has covered this with multiple coaches on the podcast — Olav Aleksander Bu's framing is the most useful: HRV is a signal, not an instruction.