Member story
Couldn't break 2 hours for a half marathon for 3 years. Everything else was optimized — training, nutrition, sleep. arq. found ferritin at 11 and Vitamin D at 16. IV iron, D3 supplementation. Ran 1:48 four months later.
Sub-optimal iron, thyroid, or vitamin D will gate every kilometre you log. Your endocrinologist reads the endurance panel quarterly, writes the supplement protocol, and the race-taper bloodwork is baked into Arq Care.
Every panel includes a 15–20 minute video consult with a specialist — read against South Asian-calibrated ranges. The AI works invisibly. The doctor does the medicine.
For three years you've optimized training, nutrition, and sleep. Your half-marathon time stays 1 hour 52 minutes. Nothing improves. Running coaches blame mental toughness. Nutritionists guess at supplements. But the real answer is in your ferritin—a marker most runners never test. The gap between good running science and great running results is a blood draw.
These biomarkers reveal the root causes — and what actually works to fix them.
Three steps. Your data. Your physician. Your protocol.
100+ biomarkers drawn at your door in 10 minutes. NABL-accredited labs. Results in 5 days. No clinic visit, no waiting rooms — just data.
Your physician reviews ferritin, thyroid, cortisol, and inflammatory markers. Why your race times stalled — identified at the biochemical level.
Iron supplementation, thyroid support, cortisol management — targeted to your specific limiters. Delivered in 48h. Retested before race season.
Iron depletion from foot-strike hemolysis, bone stress from low vitamin D, and cortisol spikes from high-volume training. A standard checkup doesn't catch these. Test ferritin, vitamin D, thyroid, and inflammation markers before your next training block.
| Biomarker | Why Runners Need It | Optimal Range | Common Runner Issue |
|---|---|---|---|
| Ferritin | Iron storage for oxygen capacity & endurance | 50–200 ng/mL (50+ for runners) | Depleted from foot-strike hemolysis; causes plateau |
| Hemoglobin | Oxygen carrying capacity | 13.5–17.5 g/dL (M), 12–15.5 g/dL (F) | Low = reduced VO₂ max, sluggish pace |
| Vitamin D | Bone strength, stress fracture prevention, immune function | 30–100 ng/mL | Deficiency = stress fractures, prolonged injury recovery |
| Calcium | Bone mineral density, force absorption | 8.5–10.2 mg/dL | Low = compromised bone architecture, injury risk |
| B12 | Energy metabolism, red blood cell formation | 200–900 pg/mL | Depleted = fatigue, sluggish recovery |
| TSH | Metabolic rate, energy availability | 0.4–4.0 mIU/L | Elevated = sluggish metabolism, unexplained fatigue |
| Cortisol (AM) | Overtraining detector, hormonal state | 10–20 μg/dL | Elevated = overtraining, suppressed adaptation |
| CRP (hs-CRP) | Chronic inflammation, recovery readiness | < 1.0 mg/L | Elevated = insufficient recovery between runs |
| HbA1c | Glucose regulation, bonking risk | < 5.7% | Elevated = insulin dysregulation, energy crashes |
| Magnesium | Muscle recovery, cramping prevention | 4.2–6.8 mg/dL | Depleted = cramping, poor recovery between runs |
Eichner ER. (1992). Foot-strike hemolysis: A diagnostic approach. The Physician and Sportsmedicine, 20(5), 103–108. — Establishes the mechanism of iron loss in distance runners through repeated foot impact and RBC destruction.
Wyon MA, et al. (2014). Prevalence of vitamin D deficiency in elite athletes. Sports Medicine, 44(2), 161–169. — Documents elevated vitamin D deficiency in runners and links to stress fracture risk.
Meeusen R, et al. (2013). Prevention, diagnosis and treatment of the overtraining syndrome. European Journal of Sport Science, 13(1), 1–24. — Framework for identifying overtraining in endurance athletes using hormonal biomarkers.
Volpe SL. (2007). Magnesium and the athlete. Current Sports Medicine Reports, 6(4), 220–223. — Reviews magnesium's role in muscle recovery and cramping prevention in distance runners.
Ferritin plateau is biochemical. If your pace has stalled, ferritin is the first suspect. Foot-strike hemolysis and dietary iron gaps are invisible without testing.
Vitamin D prevents stress fractures. Before high-mileage blocks, lock in your vitamin D. Deficiency + training volume = injury waiting to happen.
Thyroid and cortisol reveal overtraining. TSH and AM cortisol act as early-warning systems. High cortisol + low free T3 = your body is shutting down adaption.
HbA1c guides energy strategy. Glucose regulation determines bonking risk. Test quarterly to ensure your aerobic training is translating to metabolic efficiency.
No AI chat. No templates. No copy-paste PDFs. A specialist reads your panel against South Asian-calibrated ranges and writes the protocol on a 15–20 minute video consult — inside 7 days of your home draw.