# What is Heart rate variability (HRV)?

Variation in time between heartbeats; SDNN is a common summary metric in consumer apps.

## In real work

Lower HRV after poor sleep is common; trends matter more than one reading.

## Related terms

- [Atrial fibrillation (AFib)](https://prompthausapp.com/learn/atrial-fibrillation-afib.md)
- [AFib burden](https://prompthausapp.com/learn/afib-burden.md)
- [ECG (electrocardiogram)](https://prompthausapp.com/learn/ecg-electrocardiogram.md)
- [Sinus rhythm](https://prompthausapp.com/learn/sinus-rhythm.md)
- [Resting heart rate](https://prompthausapp.com/learn/resting-heart-rate.md)

## How is this different from Googling it?

Google gives a definition. Prompthaus pairs each term with how it shows up in standups, PRs, prompts, and design reviews—then quizzes you until the word sticks. One term a day on iPhone.

- Category: Health
- HTML: https://prompthausapp.com/learn/heart-rate-variability-hrv
- App Store: https://apps.apple.com/us/app/prompthaus-ai-vocabulary/id6776314407