HRV Resonance Finder

{{ cycle_seconds.toFixed(2) }} s / cycle · {{ summaryPattern }}

Age {{ age }}y {{ height_cm }} cm {{ sexLabel }} RHR {{ rhr_bpm }} bpm Warnings: {{ warnings.length }}

Age: years

Height: cm

Sex:

Resting heart rate: bpm

Exhale bias (%):

{{ exhale_bias_percent }}%

Hold after inhale (s):

Hold after exhale (s):

Vagal tone (z):

Fitness (z):

Curve width + (bpm):

Round phase durations:

Metric	Value	Copy
Resonant rate (bpm)	{{ resonance_bpm.toFixed(2) }}
Cycle length (s)	{{ cycle_seconds.toFixed(2) }}
Inhale (s)	{{ inhale_s.toFixed(2) }}
Hold after inhale (s)	{{ eff_hold_in_s.toFixed(2) }}
Exhale (s)	{{ exhale_s.toFixed(2) }}
Hold after exhale (s)	{{ eff_hold_out_s.toFixed(2) }}
Recommended window (bpm)	{{ window_low.toFixed(2) }} – {{ window_high.toFixed(2) }}
Status	{{ statusLine }}

This tool estimates a resonance-breathing pace from simple inputs; it is not a medical device. Breathe comfortably. Stop if you feel dizzy or unwell.

Categories: Calculator , Health & Fitness

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Heart rate variability (HRV) resonance is a breathing pace where your inhale and exhale align with natural rhythms to strengthen vagal influence. People also call it coherent breathing, or simply resonance breathing. A practical long‑tail you might hear is “breathing rate for vagal tone,” which describes the same idea without jargon.

You provide a few basics about yourself and your comfort preferences, then you get a breaths‑per‑minute rate and a simple pattern for inhale, optional holds, and exhale. Results include cycle length in seconds, a recommended range, and a response curve that illustrates how nearby rates compare.

For example, many adults land near a slow, even rhythm that feels calm without strain. Treat the number as a starting point and adjust by comfort, especially on days when energy or mood shifts. Stop if you feel light‑headed or unwell. This tool provides informational estimates and does not substitute professional advice.

If you prefer a longer exhale for down‑shifting, nudge the exhale bias a little and keep breathing relaxed. If training or fitness changes over time, revisit the estimate and use the highlighted window to explore small, comfortable variations.

Technical Details:

The estimator starts from a baseline rate and applies small, bounded offsets from age, standing height, sex, resting heart rate, and two optional z‑scores that proxy vagal tone and cardio fitness. The result is clamped to a plausible band and rounded to two decimals. Cycle length is the reciprocal in seconds. Inhale and exhale share the remaining cycle after any holds, split by an exhale bias. A Gaussian‑shaped response curve illustrates relative vagal response and defines a recommended window around the center. All calculations are deterministic and run in your browser.

Start with a 5.5 breaths/min baseline.
Apply age band offset, then height offset relative to 170 cm.
Add a small sex offset.
Add a resting‑heart‑rate offset with limits.
Add vagal‑tone and fitness z‑score offsets.
Clamp result to 4–8 bpm and round to two decimals.
Compute cycle length T = 60 / f_res seconds.
Subtract holds to get available time.
Split available time by exhale bias into inhale and exhale.
Build a Gaussian response and mark low/high window edges.

\begin{array}{lll} f \end{array}

_res = clamp( 4,8, round( 5.5 +Δage +Δheight +Δsex +Δrhr +Δvagal +Δfit ,2) ) T = 60f_res t_avail = max(0,T-h_in-h_out) f_ex = clamp(0,1,0.5+b/2) t_in = t_avail⋅(1-f_ex) t_out = t_avail⋅f_ex

Symbols used and their units or datatypes
Symbol	Meaning	Unit/Datatype	Source
f_res	Resonance rate	bpm	Derived
T	Cycle length	s / cycle	Derived
h_in	Hold after inhale	s	Input
h_out	Hold after exhale	s	Input
b	Exhale bias fraction	0–1	Derived from input
t_in	Inhale duration	s	Derived
t_out	Exhale duration	s	Derived
w	Curve half‑width	bpm	Derived
σ	Gaussian sigma	bpm	Derived
[low, high]	Recommended window	bpm	Derived

Estimator constants and coefficients
Constant	Value	Unit	Source	Notes
Baseline rate	5.5	bpm	Code	Starting point before offsets.
Age offsets	≤20:+0.25; 21–35:+0.10; 36–50:+0; 51–65:−0.15; 66–80:−0.30; >80:−0.45	bpm	Code	Applied once by band.
Height offset	−0.4 × (height−170)/100, clamped	bpm	Code	Clamp −0.4 to +0.4.
Sex offset	female:+0.08; other:+0.04; male:+0	bpm	Code	Small adjustment.
RHR offset	0.35 × (rhr−60)/40, clamped	bpm	Code	Clamp −0.5 to +0.5.
Vagal z	−0.12 × z	bpm	Code	Linear.
Fitness z	−0.08 × z	bpm	Code	Linear.
Width base	0.35, scaled and clamped	bpm	Code	Scale 0.7–1.4; clamp 0.15–0.8.
Window clamp	[3, 9]	bpm	Code	Applies to low/high.
Rate clamp	[4, 8]	bpm	Code	Final output band.

Units, precision & rounding: Decimal separator is a dot. Displayed values use two decimals. Optional rounding sets inhale, exhale, and holds to the nearest 0.1 s using half‑up rules. The JSON export uses numeric values; any enabled rounding is reflected in exported hold and phase durations.

Validation rules extracted from code
Field	Type	Min	Max	Step/Pattern	Error Text	Placeholder
Age	number	1	120	1	Age must be between 1 and 120.	—
Height	number	80	250	1	Height must be between 80 and 250 cm.	—
Sex	enum	—	—	male\|female\|other	—	—
Resting heart rate	number	25	180	1	Resting heart rate must be between 25 and 180 bpm.	—
Exhale bias	range	−40	40	1	—	—
Hold after inhale	number	0	—	0.1	Hold durations cannot be negative.	—
Hold after exhale	number	0	—	0.1	Hold durations cannot be negative.	—
Phase feasibility	derived	—	—	—	Holds exceed or leave no time for inhale/exhale at this rate.	—
Vagal tone z	number	−3	3	0.5	—	—
Fitness z	number	−3	3	0.5	—	—
Curve width +	number	0	1	0.05	—	—

Input and output formats
Input	Accepted Families	Output	Encoding/Precision	Rounding
Numbers	integers, decimals	Metrics	two‑decimal display	half‑up where shown
Enums	sex	CSV export	`hrv_resonance_metrics.csv`	two‑decimal text
Booleans	round durations	JSON export	`hrv_resonance_payload.json`	numeric values

Networking & storage: Processing is client‑side only. Clipboard copies and file downloads originate from the browser session. No sign‑in required.

Performance: The response curve samples 3–9 bpm in 0.05‑bpm steps (≈ 121 points), an O(n) pass with minimal memory.

Diagnostics & determinism: Identical inputs yield identical outputs. Warnings highlight atypical values; errors block infeasible phase splits.

Security considerations: Avoid pasting sensitive text in exports you plan to share. Keep breathing gentle; do not force holds beyond comfort.

Worked example: Age 35 years, height 170 cm, sex other, resting heart rate 60 bpm, no holds, no bias.

\begin{array}{lll} f \end{array}

_res=5.64 bpm T=605.64≈10.64 s t_in=5.32 s t_out=5.32 s [low, high]=[5.29,5.99] bpm

Assumptions & limitations

Heuristic estimator; not a measurement device. Heads‑up
Outputs stay within 4–8 bpm by design.
Window edges clamp to 3–9 bpm for charting.
Large exhale bias can feel uncomfortable; comfort takes priority.
Holds must leave time for inhale and exhale at the chosen rate.
Z‑scores are relative proxies, not clinical assessments.
Displayed rounding may hide very small differences.
No account for illness, medication, or acute stressors.

Edge cases & error sources

Non‑numeric input resolves to bounds.
Age, height, or heart‑rate outside limits triggers errors or warnings.
Holds that sum to the cycle halt calculations.
Extreme bias values show a comfort warning.
Rates near 4 or 8 bpm compress the exploration window.
Floating‑point rounding affects second‑decimal displays.
Clipboard or download actions may be blocked by browser policies.
Charting may not render if the visual layer fails to initialize.

Step‑by‑Step Guide:

Set your basics, preview the pattern, and breathe naturally while you explore small changes.

Enter Age and Height.
Select Sex.
Add Resting heart rate from a calm, seated minute.
Optionally add holds and adjust exhale bias for comfort.
Toggle rounding if you prefer tidy 0.1‑second phases.
Review the table, curve, and window before practicing.

Example: age 35, height 170 cm, resting 60 bpm, no holds, zero bias → about 5.64 bpm with ~10.64‑second cycles split evenly.

Keep breaths gentle, through nose when possible.
Explore within the window in 0.1–0.2 bpm steps.
Longer exhales can feel more settling; do not strain.

You finish with a personal rate and timing you can use immediately.

FAQ:

Is my data stored?

No. Calculations run in your browser. Clipboard copies and file downloads remain local to your device.

How accurate is the estimate?

It is a bounded heuristic that blends age, height, sex, resting heart rate, and optional z‑scores. Use the recommended window to fine‑tune by comfort.

What units are used?

Breaths per minute for rate, seconds for phases, centimeters for height, and beats per minute for heart rate.

What does exhale bias do?

It shifts available time toward exhale or inhale while keeping the overall cycle and any holds unchanged.

Can I use it offline?

Yes. After the page loads, computations work without a connection. Exports save to local storage locations you choose.

Why do I see warnings?

Warnings flag values outside typical ranges or comfort risks, such as very large bias or unusually high or low resting heart rate.

How do I validate my rate?

Breathe comfortably at the suggested rate, then explore within the window. Choose the pattern that feels smooth, warm, and sustainable.

Glossary:

HRV: Heart rate variability, beat‑to‑beat changes in timing.
Resonance: A breathing rate that amplifies vagal modulation.
Vagal tone: Parasympathetic influence on heart rhythm.
bpm: Breaths per minute; rate output of the estimator.
Cycle length: Seconds per full inhale‑exhale cycle.
Exhale bias: Fraction that steers more time to exhale.
Hold: Optional pause after inhale or exhale.
z‑score: Relative measure; zero is typical for the group.

HRV Resonance Finder

HRV Resonance Finder

Introduction:

Technical Details:

Step‑by‑Step Guide:

FAQ:

Glossary: