Heart rate variability and sleep tracking show how your body is responding to training. Biomarkers show what is actually happening at the biochemical level. Most serious athletes test a core set of markers two to four times per year.
The core athlete panel
Iron status (ferritin, transferrin saturation, full blood count). Hormone balance (testosterone, cortisol, often the T:C ratio). Thyroid function (TSH, free T4, free T3). Inflammation (hs-CRP). Vitamin D and B12. Lipids if cardiovascular tracking is a goal.
Iron is non-negotiable for endurance
Endurance athletes lose iron through foot strike haemolysis, GI losses and high turnover. Low ferritin caps performance long before classical anaemia appears. Many endurance athletes monitor ferritin every 3 to 4 months.
Overtraining shows on biomarkers
Persistently elevated cortisol, suppressed testosterone, rising T3 to RT3 ratio, persistent inflammation. Biomarkers can flag overtraining before performance drops or injuries appear, which is why competitive athletes test on schedule, not just when something feels wrong.
How to test cleanly
Avoid strenuous exercise for 48 hours before testing. Fast 10 to 12 hours. Test at the same time of day each round. Standardise the conditions so trends are meaningful. Chxhealth is a biomarker and genetic data provider. We do not diagnose, treat or prescribe. Our service supports your wellbeing journey alongside your healthcare professional.
Chxhealth panels for this
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Frequently asked questions
How often should serious athletes test?
Every 3 to 4 months for full panels, often timed to training blocks. Iron alone can be checked more frequently if at risk.
Does training before the test affect results?
Yes. Strenuous training raises liver enzymes, CK, inflammation markers and cortisol. Allow 48 hours of recovery before testing.
About this article. Educational content. Chxhealth is a biomarker and genetic data provider. We do not diagnose, treat or prescribe. Our service supports your wellbeing journey alongside your healthcare professional. For medical advice about your health or results, please speak to a qualified clinician.
