Heart Rate Variability
Heart Rate Variability (HRV) measures the variation in time between consecutive heartbeats — measured in milliseconds. Counterintuitively, a HIGHER HRV is better. High HRV means your nervous system is flexible and responsive, while low HRV can indicate stress, fatigue, or poor recovery. It's one of the most powerful indicators of overall health, resilience, and nervous system balance — used by elite athletes, military, and cardiologists alike.
Normal range
How Vsense measures it
Vsense calculates HRV using SDNN (Standard Deviation of NN intervals) from the facial scan signal. A higher SDNN value = more variation = healthier autonomic nervous system.
How it's scored
Above 60ms is generally good. Above 100ms is excellent. Below 30ms may indicate high physiological stress or poor recovery. Values vary significantly with age — a healthy 60-year-old will have lower HRV than a healthy 25-year-old. Gender also affects HRV: women typically have slightly lower HRV than men of the same age.
What a high reading means
A high HRV is a very positive sign. It indicates your autonomic nervous system (the part that controls stress and recovery responses) is well-balanced, you're recovering well, and your heart is flexible and resilient. Elite endurance athletes routinely have HRV above 100ms.
What a low reading means
Low HRV indicates your body is under stress — whether physical (illness, overtraining, poor sleep) or psychological. It means your nervous system is stuck in 'fight or flight' mode with reduced capacity to adapt and recover. Persistently low HRV is an independent predictor of cardiovascular events.
How to improve it
Exercise
- Moderate aerobic exercise (not too intense) is the strongest HRV booster — aim for zone 2 cardio (conversational pace)
- Yoga, especially restorative yoga and yoga nidra, significantly improves HRV within weeks
- Avoid overtraining — excessive exercise without recovery lowers HRV temporarily
- Cold exposure (cold showers or ice baths) activates the vagus nerve and can boost HRV
- Slow rhythmic breathing during exercise (especially cycling and swimming) trains the autonomic system
Diet
- Eat a diet rich in polyphenols (berries, dark chocolate, olive oil) — linked to higher HRV
- Probiotics and fermented foods (yogurt, kefir, kimchi) improve gut-brain axis and HRV
- Omega-3 fatty acids directly support autonomic nervous system balance
- Avoid alcohol before sleep — it dramatically suppresses HRV overnight, often by 20–30ms
- Adequate magnesium (leafy greens, nuts, seeds) supports vagal tone
Lifestyle
- Quality sleep is the #1 driver of HRV — aim for 7–9 hours with consistent sleep times
- Slow-paced breathing at 5–6 breaths per minute (box breathing or coherent breathing) immediately boosts HRV
- Meditation, even just 10 minutes daily, has been shown to increase HRV within 8 weeks
- Social connection and positive relationships are associated with higher HRV
- Reduce screen time and blue light exposure in the evening
- Track your HRV trend over weeks — a single reading means little; the pattern matters
Natural remedies
- The 4-7-8 breathing technique (inhale 4s, hold 7s, exhale 8s) activates the parasympathetic system
- Humming or singing activates the vagus nerve — the 'rest and digest' pathway
- Cold water face immersion for 30 seconds is a quick way to raise HRV acutely
- Ashwagandha (an adaptogen herb) has clinical evidence for reducing cortisol and improving HRV
- Ear massage (auricular therapy) stimulates the vagus nerve branch in the ear
Frequently asked questions
Is HRV more important than heart rate?
Both matter, but HRV provides more information about your nervous system's health. You can have a normal heart rate but low HRV, indicating hidden stress or poor recovery.
Why is my HRV different every day?
HRV naturally varies based on sleep quality, stress, exercise, alcohol, and even weather. That's normal. The trend over weeks matters more than any single reading.
How fast can I improve my HRV?
With consistent sleep improvement and stress reduction, you can see HRV changes within 2–4 weeks. Exercise improvements take 6–12 weeks.
What is a good HRV for my age?
Average HRV declines with age. A rough guide: 20s: 65–100ms, 30s: 55–85ms, 40s: 45–70ms, 50s: 35–60ms, 60s: 25–50ms. Being in the upper half for your age is excellent.
Does alcohol affect HRV?
Significantly — even a moderate amount of alcohol the night before can suppress HRV by 20–30ms during sleep and the following morning. This is one of the most consistent HRV findings.
Can anxiety permanently lower HRV?
Chronic, untreated anxiety does suppress HRV over time. However, HRV is very responsive to intervention — therapy, breathing practices, and exercise can restore it even after years of stress.
