Marrow reads your wearables, your training, and your labs as one continuous record — and watches for the patterns that precede injury, burnout, and illness.
Serious athletes are the most quantified people on earth — and some of the worst served by healthcare.
A 46-year-old woman running 50 miles a week sees her doctor once a year. Her resting heart rate is 42 and her cholesterol is great, so her doctor tells her she's healthy as a horse. Her ferritin is 38, which reads as normal on the lab report. Her HRV has been drifting down for two months. Her period has been irregular since January. She feels tired in a way she can't explain.
None of this shows up anywhere. Her training app tells her to hit Tuesday's intervals. Her wearable tells her she had 87 percent recovery. Her doctor told her she's fine. And somewhere in the space between all of them, she's quietly breaking down.
Marrow is for her.
Serum ferritin reads "normal" long after it matters for athletes. We track the slope, not the snapshot — and flag the trend weeks before the wall.
Ferritin dropped 44% since last spring. Most of the decline came in the past three months.
A two-week drop in heart rate variability, cross-referenced with sleep and load, often precedes illness by four to seven days. We don't wait for the cough.
A 12% drop over 14 days, paired with elevated resting HR. Consider a lighter Tuesday.
Menstrual irregularity under high load is a red flag for energy availability and bone health. We watch cycle phase alongside training and ask the right questions early.
Acute:chronic load ratios, resting heart rate creep, sleep debt. Individually quiet. Together, the signature of an athlete on the way to a bad month.
Most health apps hand you a wall of charts and leave the reading to you. Marrow hands you the pattern — named, sourced, and written in plain language — and lets you open the chart if you want to see it.
Every finding cites the specific metrics behind it, the window it covers, and the action worth discussing with your physician. No diagnosis. No alarms. Just what's quietly moving.
Garmin, Apple Health, Whoop, Oura, TrainingPeaks, and quarterly blood panels flow into a single longitudinal record.
A deterministic rules engine — authored by sports physicians, not a language model — scans your record for the dozen patterns that actually matter.
When a pattern emerges, Marrow tells you in one sentence, cites the data, and suggests a next step — usually a conversation with your physician.
Lab results via manual entry today; direct integration with quarterly blood panels is on the roadmap.
We don't tell you how to train. We tell you whether the way you're training is building you up or wearing you down.
The rules engine is written by clinicians and auditable by you. Language models never decide what to say about your health — only how to say it.
Every finding points to the specific metrics and windows behind it. No black boxes. You can always see the chart under the sentence.
HRV baselines shift across the cycle. Energy availability matters. We treat women's physiology as a starting point, not an afterthought.
We write in sentence case, in a warm declarative voice, about what's quietly moving. Tone is part of the product.
Export anything, any time. Delete anything, any time. We will never sell your health data. Full stop.
We describe patterns; we do not diagnose conditions. Findings are prompts for a conversation with a qualified physician, not a substitute for one. If a pattern concerns you, we will tell you — plainly, and without drama — and we will suggest you bring it to your care team.
Marrow is pre-launch. We're onboarding a small group of endurance athletes, masters athletes, and design partners. Leave your email and we'll be in touch when a seat opens.
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