What Counts as Low HRV?
Low HRV is relative to your age, sex, and personal baseline. General guidelines:
Clinical concern: 24-hour SDNN consistently below 50ms is associated with increased health risks.
Below average for age: Falling below the 10th percentile for your age group warrants attention. For reference: - Under 30: RMSSD below ~25ms is low - 30-50: RMSSD below ~20ms is low - Over 50: RMSSD below ~15ms is low
Personal baseline drops: A sudden 20-30% drop from your 7-day average, even if still "normal," often signals something's off.
Common Causes of Low HRV
Temporary causes (HRV rebounds within days): - Poor sleep or sleep deprivation - Alcohol consumption (effects last 2-5 days) - Acute illness or infection - Intense training or overreaching - High stress day - Dehydration - Late or heavy meals
Chronic causes (require longer-term intervention): - Chronic stress or burnout - Overtraining syndrome - Underlying health conditions - Poor cardiovascular fitness - Chronic inflammation - Sleep disorders - Anxiety or depression
Chronically Low HRV
If your HRV is consistently low for weeks or months, consider:
Medical evaluation: Rule out cardiovascular issues, thyroid problems, diabetes, and other conditions that affect autonomic function. Low HRV can be an early warning sign.
Lifestyle audit: Are you sleeping enough? Managing stress? Exercising regularly but not excessively? Avoiding alcohol?
Mental health check: Chronic anxiety and depression are associated with reduced HRV. Treating the underlying condition often improves HRV.
Gradual improvement: Don't expect overnight changes. Focus on the evidence-based interventions and track 30-90 day trends.
When Low HRV is Normal
Some people naturally have lower HRV due to genetics or age. What matters is:
- Stability: A consistently low but stable HRV is less concerning than a dropping trend - Recovery: Your HRV should still rise after rest days and good sleep - Function: If you feel good and perform well, absolute numbers matter less
Elite athletes sometimes show lower resting HRV during heavy training blocks, which normalizes during taper periods.
Action Steps for Low HRV
If it's a sudden drop: 1. Check for obvious causes (poor sleep, alcohol, stress) 2. Take an easy day or rest day 3. Prioritize sleep tonight 4. Recheck tomorrow—single readings are unreliable
If it's chronically low: 1. See a doctor to rule out medical issues 2. Implement breathing exercises (6 breaths/min) 3. Focus on sleep quality and consistency 4. Add moderate aerobic exercise 5. Consider omega-3 supplementation 6. Track progress over 8-12 weeks
Research: See clinical studies on HRV and health outcomes for context on what low HRV means for long-term health.