HRV Virtual Lab — Heart Rate Variability Analysis

Heart Rate Variability (HRV) Analysis

Objective

Understand the relationship between heart rate variability and the Autonomic Nervous System (ANS). Learn to record, analyze, and interpret HRV signals to assess cardiac health and stress levels.

Learning Outcomes

Explain HRV physiology and its significance
Calculate time-domain HRV metrics (SDNN, RMSSD)
Interpret LF/HF ratio and frequency domain analysis
Relate HRV patterns to ANS balance
Identify stress-related changes in HRV

Introduction to HRV

What is HRV?

Heart Rate Variability (HRV) refers to the variation in time intervals between consecutive heartbeats. These intervals are called RR intervals (time between two R-peaks in ECG). A healthy heart does not beat at perfectly regular intervals.

RR Intervals

RR intervals are measured in milliseconds between consecutive R-peaks in an ECG signal. Higher variability indicates better adaptability, while lower variability may suggest stress, fatigue, or pathology.

Adaptability Indicator

HRV reflects how well the heart adapts to internal and external stimuli. Higher variability means better adaptability to changing conditions, while lower variability indicates reduced adaptive capacity.

Key Insight

High HRV: Better adaptability
Low HRV: Stress, fatigue, pathology
Normal RR: 600-1200 ms
Heart Rate: 50-100 bpm

ECG Signal showing R-peaks and RR intervals — The basis of HRV analysis

The heart is regulated by the Autonomic Nervous System (ANS), which has two branches that work in balance to control heart rate and HRV.

Sympathetic Nervous System (SNS)

"Fight or Flight"

Increases heart rate
Reduces HRV
Activates during stress
Exercise response

Low HRV Pattern

Parasympathetic Nervous System (PNS)

"Rest and Digest"

Decreases heart rate
Increases HRV
Active during rest
Recovery state

High HRV Pattern

ANS Balance

HRV reflects the dynamic balance between SNS and PNS activity. A healthy individual shows good HRV, indicating proper ANS regulation and adaptability.

Balanced PNS Dominant

Equipment Familiarization

Click on each piece of equipment to learn about it. Explore ALL items before proceeding.

ECG Signal Preview

ECG System

ECG Electrodes

Lead Cables

Conductive Gel

Alcohol Swabs

HRV Software

Click on equipment to learn about it

0 / 6 explored

ECG Recording & R-Peak Detection

Record ECG signal and extract RR intervals for HRV analysis.

Select Subject Condition

Relaxed State

Resting, calm breathing

High HRV Expected

Mental Stress

Cognitive task, anxiety

Low HRV Expected

Post-Exercise

Recovery from activity

Variable HRV

Cardiac Condition

Autonomic dysfunction

Abnormal HRV

ECG Signal Monitor

HR -- bpm

RR -- ms

RR Interval Tachogram

Beats Recorded 0

Mean RR -- ms

Min RR -- ms

Max RR -- ms

HRV Analysis

Analyze the recorded RR intervals using time-domain, frequency-domain, and nonlinear methods.

Mean HR

-- bpm

Average heart rate

                                        SDNN
                                        
                                    
-- ms
Standard deviation of RR intervals
Normal: 50-100 ms

                                        RMSSD
                                        
                                    
-- ms
Root mean square of successive differences
High = Strong PNS activity

pNN50

-- %

% of intervals differing by >50ms

RR Interval Distribution

Frequency domain analysis reveals the power distribution across different frequency bands, reflecting ANS activity.

VLF: 0-0.04 Hz

LF: 0.04-0.15 Hz

HF: 0.15-0.4 Hz

LF Power

-- ms²

0.04-0.15 Hz

Mixed SNS + PNS

HF Power

-- ms²

0.15-0.4 Hz

Parasympathetic activity

LF/HF Ratio

--

ANS Balance

SNS/PNS Balance Indicator

Nonlinear methods provide advanced physiological interpretation of HRV complexity and patterns.

Poincaré Plot

Each point represents consecutive RR intervals (RRn vs RRn+1). The ellipse shape indicates HRV patterns.

SD1 -- ms Short-term variability

SD2 -- ms Long-term variability

SD1/SD2 -- Variability ratio

Clinical Applications & Interpretation

Learn how HRV analysis is applied in clinical settings and interpret your results.

Interpretation Guide

Relaxed State High HRV Strong parasympathetic activity

Mental Stress Low HRV Sympathetic dominance

Overtraining Decreasing HRV Fatigue, need for recovery

Cardiac Disease Abnormal HRV Autonomic dysfunction

Clinical Applications

Stress Monitoring

Track stress levels and autonomic balance in workplace wellness programs.

Cardiac Risk Assessment

Predict cardiovascular events and assess post-MI prognosis.

Sleep Quality

Evaluate sleep stages and recovery quality through overnight HRV.

Mental Health

Monitor depression, anxiety, and emotional regulation.

Athletic Performance

Optimize training load and monitor recovery in athletes.

ICU Monitoring

Continuous autonomic assessment in critical care patients.

Factors Affecting HRV

Age

Breathing Rate

Physical Fitness

Stress Level

Caffeine

Medications

Your Analysis Summary

Complete the recording and analysis steps to see your results here.

Lab Complete!

You have successfully completed the HRV Virtual Lab experiment.

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HRV Virtual Laboratory

Heart Rate Variability (HRV) Analysis

Objective

Learning Outcomes

Introduction to HRV

What is HRV?

RR Intervals

Adaptability Indicator

Key Insight

Sympathetic Nervous System (SNS)

Parasympathetic Nervous System (PNS)

ANS Balance

Equipment Familiarization

ECG Recording & R-Peak Detection

Select Subject Condition

Relaxed State

Mental Stress

Post-Exercise

Cardiac Condition

ECG Signal Monitor

RR Interval Tachogram

HRV Analysis

Mean HR

SDNN

RMSSD

pNN50

RR Interval Distribution

LF Power

HF Power

LF/HF Ratio

Poincaré Plot

Clinical Applications & Interpretation

Interpretation Guide

Clinical Applications

Stress Monitoring

Cardiac Risk Assessment

Sleep Quality

Mental Health

Athletic Performance

ICU Monitoring

Factors Affecting HRV

Your Analysis Summary

Lab Complete!

HRV Glossary

HRV (Heart Rate Variability)

RR Interval

SDNN

RMSSD

pNN50

LF (Low Frequency)

HF (High Frequency)

LF/HF Ratio

ANS (Autonomic Nervous System)

SNS (Sympathetic Nervous System)

PNS (Parasympathetic Nervous System)

Poincaré Plot

SD1

SD2

R-peak