Estimate stress from HR, breathing rate, and optional HRV. Guided breathing pacer with 4 patterns included.
Log physiological readings to estimate stress level and get personalised relaxation guidance. Includes a breathing pacer. Educational only.
Used to normalise HR score — avoids penalising fit individuals with low resting HR.
Breathe with the expanding circle. Each cycle follows the pattern you select.
Stress is the body's response to any demand — physical, psychological, or environmental — that it perceives as exceeding its coping resources. The physiological stress response, often called the 'fight-or-flight' response, triggers a cascade of hormonal and autonomic changes designed to mobilise energy and heighten alertness.
The sympathetic nervous system drives the acute stress response: heart rate increases, breathing accelerates, stress hormones (adrenaline and cortisol) are released, and blood is redirected to muscles. This response is adaptive in the short term but becomes damaging when chronically activated.
Chronic stress is associated with elevated risk of cardiovascular disease, immune suppression, gastrointestinal dysfunction, sleep disruption, anxiety, and depression. Understanding how to measure physiological markers of stress — and respond to them — is a meaningful component of preventive health.
The checker estimates a physiological stress score (0–100) from two primary inputs — heart rate and breathing rate — and an optional third input: Heart Rate Variability (HRV). Each is normalised and combined using empirically informed weights.
Heart rate contribution (50–62%): Current heart rate is compared against your personal resting heart rate to produce a relative elevation score. Normalising against your resting rate avoids penalising physically fit individuals who have lower absolute resting heart rates.
Breathing rate contribution (30–38%): A resting adult breathes 12–18 times per minute. Rates above this indicate sympathetic activation. The contribution is normalised against a practical range of 6–30 breaths per minute.
HRV contribution (20%): Heart rate variability — the beat-to-beat variation in heart rate — is a reliable marker of parasympathetic (rest-and-digest) activity. Higher HRV indicates greater parasympathetic tone and lower stress. When HRV is provided, it replaces a proportion of the HR/breathing weighting with its inverse-normalised value (higher HRV → lower stress contribution).
A score of 0–29 is classified as Low stress — physiological parameters suggest a calm, parasympathetically dominant state. This is the optimal zone for recovery, digestion, immune function, and focused cognitive work.
30–54 is Mild stress — a moderate level of sympathetic activation that may reflect light exercise, mild anxiety, or early fatigue. Brief breaks, movement, or a short breathing exercise are typically sufficient to restore balance.
55–74 is Moderate stress — a meaningful elevation indicating significant sympathetic arousal. Sustained moderate stress can impair sleep, concentration, and mood. Structured relaxation techniques — box breathing, progressive muscle relaxation, or brief mindfulness — are appropriate responses.
75–100 is High stress — suggesting marked physiological arousal. If accompanied by chest tightness, dizziness, or shortness of breath, these symptoms should not be dismissed as purely stress-related without clinical evaluation. The checker recommends immediate breathing techniques and, where stress is persistent, professional support.
Slow diaphragmatic breathing is one of the most immediately effective stress reduction tools available. Breathing at 4–6 cycles per minute (approximately 5 seconds inhale, 5 seconds exhale) strongly activates the baroreflex and increases HRV, shifting the autonomic balance toward parasympathetic dominance within minutes.
Box breathing (4-4-4-4) is a structured technique used by emergency responders, military personnel, and athletes: inhale for 4 seconds, hold for 4 seconds, exhale for 4 seconds, hold for 4 seconds. Its predictable rhythm facilitates focus while simultaneously slowing heart rate and breathing rate.
Progressive muscle relaxation (PMR) involves systematically tensing and releasing muscle groups from feet to head. The contrast between tension and release deepens the experience of muscular relaxation and is effective for both acute stress and chronic tension-related symptoms.
HRV biofeedback, which this tool supports through real-time score changes as you adjust breathing, has a strong evidence base for reducing physiological markers of stress and improving autonomic regulation. Regular practice over weeks produces lasting improvements in resting HRV and stress resilience.
The breathing pacer built into this tool guides you through slow breathing at a target rate, providing the rhythmic visual prompt that makes it easier to sustain the optimal breathing frequency during a relaxation session.
Normal and clinically significant respiratory rate ranges for adults and children at rest. Breathing rate is measured as breaths per minute (bpm) and is one of the four classic vital signs.
| Respiratory Rate (breaths/min) | Classification | Clinical Notes |
|---|---|---|
| < 8 | Bradypnoea (adult) | Abnormally slow; investigate cause (e.g. opioid effect) |
| 8–11 | Low normal | Seen in very fit individuals at rest; generally benign |
| 12–18 | Normal (adult) | Typical resting adult range |
| 18–20 | Upper normal | Can reflect mild stress, anxiety, or light exertion |
| 20–24 | Mild tachypnoea | May indicate pain, early infection, or anxiety |
| 25–29 | Tachypnoea | Clinically significant; assess for respiratory or systemic cause |
| ≥ 30 | Severe tachypnoea | Medical concern; seek clinical evaluation |
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