I've been getting bloodwork 3-6 times a year since 2014. I have 51 panels going back twelve years. I spent a decade at InsideTracker, the main innovator when it comes to blood analytics. And I still didn't notice that my ferritin craters every summer. The data was never the issue. Having something that could hold all of it in working memory at the same time was. I wrote about what happened when I pulled 12 years of Strava, 51 blood panels, and my full training log into Claude and asked it to tell me what was interesting. Here's the short version: IRON My ferritin craters every summer and I never noticed. Moving to Colorado dropped my average ferritin 19% permanently. Altitude forces your body to make more red blood cells, and that process drains your iron stores as a structural tax whether you're training hard or not. My best performances cluster around my highest ferritin readings. My worst effort ever; Four Pass Loop, no power on any climb; was ferritin 45, Tsat 19%. My marathon PR of 2:59 was run with ferritin 17 points below my career average. I don't know what I left on that course. INJURY Most predictable trigger across 8 years: a travel-related volume drop followed by a full return to normal load with no adjustment. 50 mile week → 18 mile week → back to 50. Something breaks every time. October and January are my highest injury months. The fix: never exceed 1.25x your 4-week average after a down week, no matter how good you feel. SAUNA 331 sessions logged since 2018. Weeks with 2+ sessions correlate with a 36% lower injury signal the following week. When already dealing with something, sauna weeks resolve 35% faster. My best fitness years had the most sauna. I'm currently at 3.6% of days and my hip is flaring. Not a coincidence. FITNESS VO2max 63.3 at sea level. LT2 at 6:19/mi. Both tested September 2025. Controlled HR at 142 bpm while training at 5,280 feet. I'm probably in the best aerobic shape of my life and haven't had the right race to prove it. RUNNING PARTNERS Pulled pace and subjective feel scores across every logged run, classified by partner. Two people consistently get me to 7:44–7:49/mi on what should be easy runs; highest feel scores in the dataset. Running is measurably better when you're not doing it alone. WEATHER 0.27 seconds per mile slower per degree Fahrenheit on road runs. Below 45°F I average 8:24/mi. Above 75°F it's 8:50/mi. November is my fastest month. June is my slowest. All of this is the easy part. Pattern matching is becoming a commodity. The hard part is what happens next; someone accountable who can examine you, order the follow-up test, and adjust the plan when your labs come back. That's what I wrote about this week, and it's what @Eternal is built to be: longrunlabs.substack.com/p/w…