How to use HRV in training (and when to ignore the app)

Heart rate variability is popular because it promises a clean answer: green means go, red means rest. Endurance athletes learn fast that the answer is rarely that clean.

On Fast Talk Episode 358, Griffin McMath and Chris Case talk with Dr. Brad Lichtenstein — naturopathic physician, biofeedback trainer, and long-time HRV educator — plus coaches and athletes who actually use the metric day to day. The useful frame is simple: HRV is a tool for recovery context, not a coach that overrides how you feel.

Listen: Fast Talk Labs · Apple Podcasts

This article translates that episode into a practical N+One decision loop for cyclists using Whoop, Garmin, Oura, or similar stacks.

What HRV actually measures

Heart rate is beats per minute. HRV is the change in time between beats. More variability usually signals a more flexible autonomic system — often more parasympathetic influence at rest — but “higher is always better” is a trap.

Lichtenstein’s caution: a static heart (think pacemaker-like regularity) is not healthy adaptability, yet a single high reading can also mean you measured poorly, breathed differently, or are getting sick. You need heart rate and HRV together, plus context.

Short wearable readings (typical consumer apps) usually lean on time-domain metrics such as RMSSD that heavily reflect parasympathetic influence. That is useful for morning recovery trends. It is not the same thing as a 24–48 hour Holter SDNN reading from cardiology.

Use it for recovery trends — not overnight gospel

For athletes, the most practical job of HRV is answering: did I recover from yesterday’s load and life stress enough to absorb today’s quality work?

Best practices from the episode:

1. Prefer a consistent morning reading over treating overnight sleep-HRV as the sole readiness verdict. Sleep metrics from wearables are inferred (movement, HR, temperature), not EEG sleep stages.
2. Same conditions every day. Sit, stay still, similar time. Posture changes HRV (lying ≠ sitting ≠ standing). Breathing rate changes short-term HRV via respiratory sinus arrhythmia — five to seven calm breaths per minute is not comparable to rushed twelve.
3. Build a baseline before you trust day colors. Many solid apps need about a week to a month of consistent measures (coefficient of variation) before “ready / not ready” means much. See HRV baselines.

Measurement reality: chest strap vs wrist/ring

• Chest strap (electrical / ECG-like): usually cleaner for a deliberate morning check; less motion artifact.
• PPG (wrist, ring, phone camera): convenient, improving, but sensitive to movement, light leak, cold hands / Raynaud’s, scar tissue, and which wrist you use.

If you will not wear the “more accurate” device, wear the one you will actually use consistently. Consistency beats theoretical purity.

How coaches and athletes actually use it

• Isaiah Newkirk: check whether the training response freshened the athlete; also watch travel and altitude weeks, not only hard intervals.
• Julie Young: useful when athletes struggle to be objective about recovery — and dangerous when a red score toys with race-week psychology. She still leans hard on resting heart rate patterns for simplicity.
• Jack Burke: overnight tracker often just confirms what he already feels. His rule of thumb: one bad night → train as planned; two or three in a row → adjust. Lichtenstein’s refinement: use the morning HRV/heart-rate pair to decide whether this bad night landed or bounced.

When not to use HRV

Stop or park the wearable when:

• The app creates more anxiety than insight (“my device said I slept poorly, so I must have”).
• You start training to raise the HRV score instead of using it as feedback.
• Race week / A-event proximity — many pros deliberately ignore the screen so psychology stays clean.