Health Monitor
The Health Monitor combines objective biological signals with subjective symptom reports to provide an early warning system for illness, overreaching, and health deterioration.
Early detection of illness in athletes
Research in sports medicine has shown that several physiological markers change measurably before an athlete subjectively feels ill. These changes are driven by the immune system's activation and the accompanying autonomic nervous system response:
- HRV suppression: immune activation suppresses parasympathetic tone, reducing RMSSD below personal baseline.
- Elevated resting heart rate: the sympathetic nervous system increases heart rate as part of the immune response.
- Elevated respiratory rate: early respiratory infections increase breathing frequency before obvious symptoms appear.
- Reduced blood oxygen (SpO₂): respiratory compromise can reduce arterial oxygen saturation.
Combining these biological signals with self-reported symptoms creates a more robust early warning system than either approach alone.
What Flux monitors
Biological signals
Morning HRV
Compared to your 40-day rolling average. A significant deviation below baseline is a key illness indicator.
Resting Heart Rate
Compared to your 40-day rolling average. Elevated RHR above your norm signals physiological stress or infection.
Respiratory Rate
Normal range is approximately 12–20 breaths per minute. Flux compares your overnight rate to your personal baseline.
Blood Oxygen (SpO₂)
Healthy baseline is ≥ 96%. Values below this range — especially sustained low readings — may indicate respiratory compromise.
Training Load Balance (ACWR)
The ratio of acute to chronic training load. A significantly elevated ratio (sudden spike in load) is a known risk factor for illness and injury.
Sleep Score
Chronic poor sleep is strongly linked to immune suppression and increased susceptibility to upper respiratory infections.
Subjective symptom report
Through the optional daily questionnaire, Flux incorporates self-reported symptoms that are known early indicators of illness:
Illness Risk Score & Health Status Score
Flux produces two related outputs from the Health Monitor:
Illness Risk Score (IRS)
Derived entirely from objective biological signals. It quantifies the physiological risk of illness or overreaching based on deviations from your personal baselines and established biomarker thresholds.
Health Status Score (HSS)
Combines the IRS with the subjective symptom questionnaire. Self-reported symptoms add an important layer — they can confirm biological signals or raise the risk level even when objective markers are not yet deviating.
How to use the Health Monitor
- Check the Health Monitor daily alongside your Recovery Score.
- Elevated biological signals + symptoms = consider reducing training load significantly.
- Biological signals elevated but no symptoms = monitor closely; avoid high-intensity sessions.
- Complete the symptom questionnaire regularly — it significantly improves detection accuracy.
- If the Health Monitor shows high risk, prioritise sleep, nutrition, and rest over training.