What Ironman athletes need to track
Ironman training is arguably the most demanding endurance project an amateur athlete can take on - 20+ hours a week across three sports for 16-30 weeks, with nutrition, sleep, work, and family competing for the same bandwidth. The central challenge isn't any single workout; it's managing the cumulative load across sports and knowing when you're building fitness vs. digging a recovery hole you won't climb out of before race day.
Baseline gives Ironman athletes a unified dashboard that brings together swim, bike, and run data from every device - Garmin, Wahoo, Coros, Apple Watch, WHOOP, Oura - and correlates it with recovery metrics. Instead of trying to eyeball whether your bike TSS plus run TSS plus swim TSS is too much for your current recovery capacity, Baseline computes your combined training load (CTL) and training stress balance (TSB) across all three sports. The key metrics are your sport-specific TSS per week, your pace and power trends across disciplines, your run-brick decoupling (how you run off the bike), and your recovery readiness trend. These numbers tell you whether your training week is productive or destructive.
Goal-specific KPIs Baseline surfaces
Multi-sport training load (CTL/ATL/TSB). Ironman training load is the sum of swim, bike, and run Training Stress Score (TSS) accumulated over time. Baseline computes your combined Chronic Training Load (42-day average), Acute Training Load (7-day average), and Training Stress Balance across all three sports. A TSB of -20 to -30 is normal during peak Ironman training; anything below -40 warrants a recovery week. The combined curve tells you if your total load is manageable or if you're stacking fatigue across sports.
Brick session analysis (run off the bike). The Ironman run is the hardest leg because your legs are already fatigued from cycling. Baseline tracks your run pace and heart rate during brick sessions (bike followed immediately by run) and compares them to standalone run performances. The difference - how much slower you run off the bike - is your brick decoupling. A trend of improving brick pace means your race-day run will feel better.
Sport-specific TSS distribution. Baseline shows your TSS broken down by sport per week, so you can see whether your bike volume is crowding out your run or vice versa. For Ironman, the typical distribution is roughly 50% bike, 35% run, 15% swim TSS. If your swim is taking more than 20% of your total load, you're likely spending too much energy in the pool relative to the race distance.
FTP (bike) and critical pace (run). For the bike leg, Baseline tracks your Functional Threshold Power from your actual rides. For the run, it tracks your critical pace from your recent best efforts. Both metrics trend over time so you can see whether your bike and run fitness are improving together or diverging. A rising FTP with a flat critical pace means you're favoring bike training - a common Ironman pitfall.
Swim pace and stroke efficiency. Baseline imports swim data including pace per 100m, stroke rate, SWOLF, and distance. While swim is the shortest leg, it's also the most technique-dependent. Baseline tracks your swim pace trends over time and correlates them with your total training load to identify when fatigue affects your stroke efficiency.
Recovery readiness (HRV, resting HR, sleep). An Ironman block demands more recovery than any single-sport program. Baseline surfaces your overnight HRV, resting heart rate, and sleep trends from WHOOP, Oura, Garmin, or Apple Health. When your HRV drops below baseline for 3+ consecutive days while your training load is increasing, you're heading toward overtraining. Baseline shows this correlation directly.
Heart rate decoupling across sports. Baseline tracks how your heart rate drifts at a given pace or power in each sport. A rising decoupling rate in the last 30 minutes of your long ride or run signals that your fueling or endurance base needs attention. Because Ironman training has so many variables, seeing decoupling trends in context with your total load is more actionable than any single workout metric.
Recommended pricing tier for this goal
Ironman athletes generate data from the most devices of any endurance athlete - a GPS watch (Garmin Fenix or Coros), bike computer (Wahoo or Garmin), power meter, heart rate strap, and a recovery wearable (WHOOP, Oura, Apple Watch). The best plan is Baseline Pro at $12/month or $249 lifetime, which unlocks unlimited device integrations, AI-powered daily insights across all three sports, the full-resolution heatmap, geographic stats to compare training camps, the achievement system, and race time predictor. A single Ironman entry fee covers years of Baseline Pro.