Understand the Report

Every parameter, explained.

Choose a report layer. Each parameter shows what it measures, how it is derived, typical reference values and what higher or lower readings usually indicate. Reference values are for short-term resting recordings in healthy adults and vary with age, sex, fitness and time of day, so compare a person mainly with their own previous scans.

Autonomic Nervous System

The autonomic nervous system runs everything you do not consciously control: heart rate, blood pressure, digestion, breathing pattern, temperature and the stress response. Its two branches work like an accelerator (sympathetic) and a brake (parasympathetic). Health depends less on either branch alone than on flexible switching between them. This layer summarises that balance.

Established physiology

Derived from validated HRV components and expressed against age-matched reference bands.

SNS

Sympathetic Activity Index

Score, age-referenced

Measures: Relative drive of the fight-or-flight branch at rest.
Derived from: Mean heart rate, Stress Index and normalised LF power combined into one index. No single HRV value is a pure sympathetic marker, so a composite is used.
Higher means: Ongoing stress load, poor sleep, stimulants, pain, inflammation, dehydration or overtraining. Persistently high resting sympathetic tone is associated with higher cardiometabolic risk.
Lower means: Usually a calm resting state. Very low values together with low parasympathetic activity suggest overall autonomic depletion rather than relaxation.

PNS

Parasympathetic Activity Index

Score, age-referenced

Measures: Vagal rest-and-digest influence on the heart.
Derived from: RMSSD, HF power and Poincaré SD1, the three most robust vagal markers.
Higher means: Good recovery capacity, cardiorespiratory fitness and emotional regulation. Common in trained individuals.
Lower means: Reduced vagal tone, seen with chronic stress, sedentary lifestyle, insulin resistance, low mood and ageing. Low vagal tone is one of the most replicated risk markers in HRV research.

ANS-B

ANS Balance

Two-axis chart

Measures: Where the person sits on a map of sympathetic versus parasympathetic activity.
Derived from: The SNS and PNS indices plotted against each other, with a central zone for balanced regulation.
How to read: Upper left, stress dominant. Lower right, recovery dominant. Lower left, low overall activity, suggesting fatigue or depletion. Upper right, high overall activity, often seen in fit individuals or acute arousal.
Clinical use: The most useful single picture for client education and for tracking response to breathwork, sleep, nutrition or therapy.

Stress Index (Baevsky)

Arbitrary units

Measures: Degree of tension in the regulatory systems; how narrowly the heart rhythm is being held.
Formula: SI = AMo ÷ (2 × Mo × MxDMn), using the mode of the NN interval histogram, the share of beats in the modal bin and the range of intervals.
Reference: About 50 to 150 at rest in healthy adults.
Interpretation: 150 to 500 indicates moderate strain; above 500 indicates marked strain, as during illness, acute stress or exhaustion. Very low values with low HRV can reflect poor regulation rather than calm.

ARI

Adaptive Reserve Index

Score 0 to 100

Measures: How much regulatory capacity remains to absorb new stress.
Derived from: Total power, SDNN and DFA α1 weighted against the Stress Index.
Higher means: A resilient system with headroom for training, travel, workload or recovery from illness.
Lower means: Limited reserve. Practitioners typically prioritise sleep, recovery and stress reduction before adding intense interventions.

HR · RR

Resting Pulse and Respiratory Rate

bpm, breaths/min

Measures: Average pulse during the recording and breathing rate estimated from respiratory sinus arrhythmia.
Reference: Pulse 60 to 80 bpm typical; breathing 10 to 18 per minute.
Clinical use: A higher resting pulse is independently linked with cardiovascular risk. A fast breathing rate at rest often accompanies sympathetic dominance and is a direct target for breath training.

The sample report

See these parameters on a real report.

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