The Short Version
The claim overstates what current evidence supports. While the TRUE-HF AI model uses Apple Watch data to estimate daily fitness surrogates correlated with pVO2, the Apple Watch does not directly measure peak oxygen uptake — it estimates submaximal VO2max with known error and bias. Published findings show promising risk associations (e.g., threefold higher event risk per 10% fitness drop), but no validated "high accuracy" prediction metrics (AUC, sensitivity, specificity) for heart failure have been reported for this specific pVO2-based approach. The research is promising but preliminary.