What Is Heart Rate Variability (HRV)?
Heart rate variability (HRV) is the variation in time between consecutive heartbeats, measured in milliseconds. Even at a steady heart rate, the gaps between beats are not identical. HRV reflects the activity of the autonomic nervous system and is tracked by many wearables as an indicator of recovery and stress.
Interpreting HRV
Values vary widely between individuals by age and fitness, so trends over time for the same person are more informative than comparisons with others.
What Influences It
Sleep, stress, illness, alcohol, and training load can all affect HRV.
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🔗 Related Terms
More Health & Fitness Terms
- Basal Metabolic Rate (BMR)
- Body Composition
- Body Fat Percentage
- Body Mass Index (BMI)
- Calorie
- Calorie Deficit
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Last updated: September 29, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.