VO2Stats: VO2 Max Calculator app analytics for October 7

VO2Stats calculates your VO2 max using nine peer-reviewed scientific methods - giving you a richer, more complete picture of your aerobic fitness than any single estimate can provide. -- NINE METHODS -- Jack Daniels VDOT - converts your running pace and distance into a VDOT fitness score, the gold standard used by coaches worldwide. Submaximal HR (Firstbeat-style) - models the relationship between heart rate and running speed, extrapolated to your maximum. Uth-Sorensen - uses the ratio of your maximum to resting heart rate. Simple and effective for trend tracking. Rockport Walk Test - ideal for lower-fitness individuals; based on a 1-mile walk and end heart rate. Cooper 12-Min Run - estimates VO2 max from how far you can run in 12 minutes. Non-Exercise / Wier - requires no workout; uses age, body metrics, and daily activity data. HR Recovery - faster heart rate recovery after exercise correlates strongly with higher VO2 max. Astrand-Rhyming (Cycling) - submaximal cycling test using power output and steady-state heart rate, with age correction. Coggan FTP (Cycling) - derives VO2 max from your best 20-minute cycling power, normalized to body weight. -- FEATURES -- Dashboard - see your best current estimate with confidence rating, plus a summary of all active methods at a glance. History - track how your VO2 max has changed over 3 months, 6 months, 1 year, 2 years, or all time. Fitness categories adjust for your age at each point in time, so improving thresholds are always compared fairly. Compare - plot all nine methods on one chart to see how they align. A spread indicator tells you when methods agree. Methods Guide - a full reference explaining each algorithm, its scientific source, the data it needs, and its limitations. Fitness categories are personalized to your age and sex from Apple Health. Confidence indicators - each estimate shows a signal-strength badge (Rough / Fair / Reliable) based on the quality and quantity of data available. -- PRIVATE BY DESIGN -- All calculations run entirely on your iPhone. VO2Stats reads from Apple Health and never writes to it. No account required. No cloud sync. No advertising. No analytics. Your health data never leaves your device. -- IMPORTANT -- VO2Stats is a fitness and wellness tool for informational purposes only. It is not a medical device and is not intended to diagnose, treat, or replace clinical VO2 max testing. Accuracy varies based on available data, individual physiology, and workout conditions. Consult a healthcare professional before making health decisions based on any fitness metric.