Heart Rate Variability (HRV) measures the variation in time between heartbeats. Counterintuitively, MORE variability is better - it indicates a flexible, resilient nervous system.
Understanding HRV
Your autonomic nervous system has two branches:
- Sympathetic: “Fight or flight” - stress response
- Parasympathetic: “Rest and digest” - recovery mode
High HRV = Strong parasympathetic activity = Good recovery Low HRV = Sympathetic dominance = Stress/fatigue
What Affects HRV?
Negative Impact:
- Poor sleep
- Alcohol
- Overtraining
- Illness
- Chronic stress
- Dehydration
Positive Impact:
- Quality sleep
- Meditation
- Proper recovery
- Good nutrition
- Consistent exercise
- Breathing exercises
Using HRV for Training Decisions
High HRV Day: Go hard - your body is ready for stress Low HRV Day: Take it easy - focus on recovery
Morning vs Night Measurements
Measure at the same time daily for consistency. Morning readings (before coffee, before getting up) are most reliable.
Track with Pulselyze
Connect your Oura, Apple Watch, or Whoop to see HRV trends. We correlate HRV with your training load, sleep, and weight changes to find your optimal patterns.