HRV for Beginners: What It Is, Why It Matters & How to Track It Free

Heart Rate Variability isn't just for elite athletes anymore. If you have an iPhone, you already have everything you need to start tracking your recovery — starting today.

7 min read
Beginner-friendly
ESC 2021 sourced
LIVE · 14 / 60s
9:41● ● ●
Measurement complete
Your HRV today.
68 ms
Heart-rate variability
Excellent
RMSSD
68 ms
+6% · parasympathetic
SDNN
91 ms
+3% · autonomic
7-day trend
↑ up 4%
What is HRV

The variation between heartbeats — your nervous system's report card.

RMSSD vs SDNN

Two metrics, one number. Why Pulse shows both — and which to watch.

TRIMP load

Training-impulse: your weekly training load, in one chart.

The protocol

4 steps. Sixty seconds. Done before your coffee.

  1. 01
    Morning

    Understand the Basics

    HRV measures the millisecond variation between consecutive heartbeats. Higher variability signals your nervous system is in a well-recovered, adaptable state. Lower variability signals fatigue or stress.

  2. 02
    60 sec

    Start with 14 Days of Data

    HRV only becomes useful once you have a personal baseline to compare against. Commit to 14 consecutive morning readings before drawing any conclusions. Pulse Rate builds your baseline automatically.

  3. 03
    Read

    Focus on Trends, Not Absolute Numbers

    An HRV of 40ms might reflect excellent recovery for one person and poor recovery for another. What matters is whether YOUR number is trending up, flat, or down relative to YOUR baseline.

  4. 04
    Daily

    Use HRV to Guide Your Week

    On mornings when HRV is well above your baseline, your body is ready for a challenging effort. On low-HRV mornings, prioritize easier movement, extra sleep, and stress management.

What you'll see in Pulse

Your progress, exactly how the app shows it.

The same chart that lives on your iPhone's Progress screen — rebuilt so you know what you're looking at.

Wellness Index trend
82 / 100 Excellent
Last 30 days
100 75 50 25
Excellent (80+) Borderline (40–60) Very low (0–40)
Excellent 80+

Outstanding score. Your key heart metrics are above normal.

Normal 60 – 80

Most healthy adults fall within this range.

Borderline 40 – 60

Not necessarily alarming — but worth monitoring.

Very Low 0 – 40

If this persists, please consult a healthcare professional.

Bonus · TRIMP

Training Impulse, decoded.

TRIMP = duration × intensity. A 60-minute easy run scores about 70 TRIMP. A 30-minute interval session scores 110. Pulse adds them up daily and tells you when your week is too light, just right, or about to overcook you.

80–140
Optimal weekly load
140–200
Stretch (watch HRV)
200+
Overreaching
More guides

Take your first reading.

You've already got the hardware — your iPhone. Pulse does the rest.

Free to download · Core tracking always free · iOS 15+

Download on the App Store