What does an HRV (Heart Rate Variability) average of 37 indicate about a person's health?

HRV Average of 37: Clinical Interpretation

An HRV average of 37 milliseconds is considered low and indicates impaired autonomic nervous system function, which significantly increases your risk of cardiovascular disease and overall mortality by 2-3 times, requiring immediate cardiovascular evaluation. 1, 2

Understanding Your HRV Value

Your HRV of 37 milliseconds falls below optimal ranges and represents compromised autonomic regulation:

• The American Heart Association defines HRV values of 18-25 milliseconds as significantly impaired autonomic function, and your value of 37 ms, while higher than this critical threshold, still indicates reduced parasympathetic nervous system activity 2
• Low HRV directly reflects decreased autonomic nervous system regulatory capacity, specifically showing diminished parasympathetic (vagal) tone 2
• This measurement indicates your heart's reduced ability to adapt to physiological and environmental stressors 3

Mortality and Cardiovascular Risk

The evidence clearly demonstrates that low HRV like yours carries substantial health risks:

• Multiple studies show that low HRV increases all-cause mortality risk by 2-3 times in general populations 1, 4
• The ATRAMI study specifically demonstrated that patients with low HRV had a relative mortality risk of 3.2 times, independent of other cardiac factors 1, 2
• Meta-analysis data shows low HRV is associated with a 32-45% increased risk of first cardiovascular events in populations without known cardiovascular disease 5
• Importantly, low HRV is a better predictor of non-arrhythmic death (such as heart failure progression) rather than sudden cardiac death 1, 4

Critical Underlying Causes to Investigate

You need immediate evaluation for these specific conditions:

Cardiovascular Disease

• Post-myocardial infarction - one of the most established causes of reduced HRV 4
• Congestive heart failure - low HRV correlates with disease severity and left ventricular dysfunction 4
• Coronary artery disease - commonly presents with reduced HRV 2
• Cardiomyopathy (dilated or ischemic) - associated with decreased HRV 2, 4

Sleep Breathing Disorders

• Sleep apnea - a common cause of low HRV during sleep, leading to sympathetic enhancement and parasympathetic reduction 2
• Sleep apnea can trigger arrhythmias, particularly during REM sleep 2

Metabolic and Lifestyle Factors

• Hypertension - low HRV is a predictor of hypertension development 2, 6
• Diabetes - affects autonomic function and reduces HRV 3
• Physical deconditioning - reduces HRV through diminished cardiovascular fitness 4
• Obesity - affects HRV through altered autonomic balance and increased sympathetic activity 4

Required Clinical Evaluation

You must complete these specific assessments immediately:

Cardiovascular Workup

• Electrocardiogram (ECG) - to evaluate cardiac rhythm and detect ischemic changes 2
• Echocardiogram - to assess left ventricular function and ejection fraction 2
• 24-hour Holter monitoring - to evaluate for arrhythmias and continuous HRV patterns 2
• Exercise stress test - to evaluate cardiovascular reserve and heart rate response to activity 2

Sleep Assessment

• Polysomnography (sleep study) - to rule out sleep apnea and evaluate sleep quality 2
• Multiple sleep latency test - to assess sleep structure and breathing patterns 2

Metabolic Screening

• Blood pressure monitoring - assess for hypertension 2
• Fasting glucose and HbA1c - screen for diabetes 2
• Lipid panel - evaluate cardiovascular risk factors 2

Evidence-Based Interventions to Improve HRV

While awaiting evaluation, these interventions can improve your HRV:

• Regular aerobic exercise - consistently shown to improve HRV parameters and counteract sedentary behavior effects 3
• Stress reduction practices - mind-body interventions that activate parasympathetic nervous system (meditation, yoga) 3
• Sleep optimization - address sleep disorders and maintain regular sleep patterns 3
• Controlled breathing exercises - slow, controlled breathing (approximately 6 breaths per minute) enhances HRV by increasing parasympathetic activity 3, 4
• Lifestyle modifications - reduce alcohol consumption, smoking cessation, and weight management 3

Important Clinical Caveats

Key considerations for interpreting your HRV:

• HRV measurements require standardized conditions - ideally 4-5 minutes of controlled breathing at 15 breaths/minute to avoid artifacts 2
• Short-term HRV has moderate repeatability in healthy individuals but poor repeatability in heart failure patients 2
• Circadian rhythms and activity levels influence HRV measurements throughout the day 4
• The DINAMIT trial showed that in post-MI patients with low HRV, the increased mortality was primarily from advanced heart failure rather than arrhythmic death 1, 4

Do not delay cardiovascular evaluation - your HRV value of 37 ms warrants immediate medical assessment to identify and treat underlying cardiovascular or systemic disease. 2