What is a good HRV score?

There is no universal good score. HRV is highly individual, so compare today's reading against your own baseline trend rather than population averages.

Why did my HRV drop overnight?

Common causes include poor sleep, alcohol, dehydration, heavy training load, acute stress, travel, and early illness.

Should I skip a hard workout when HRV is low?

If HRV is low for multiple days and you also feel fatigued or sleep-deprived, reducing intensity is usually the better choice. One isolated low day may be noise.

Is HRV better measured at night or in the morning?

Both can work if the method is consistent. Overnight wearable trends are convenient, while morning spot checks can also be reliable when done under the same conditions each day.

What Is HRV and Why Athletes Track It

HRV (heart rate variability) is the variation in time between heartbeats. Higher HRV, relative to your personal baseline, usually means better recovery and nervous system readiness. Lower HRV can indicate stress, poor sleep, illness, or accumulated training fatigue.

HRV is one of the most misunderstood metrics in fitness. People often compare raw HRV numbers with friends, but that is the wrong move. HRV is highly individual. The only useful question is: how does today's value compare to your own baseline trend?

What HRV actually measures

Your heartbeat is not perfectly metronomic. Micro-variation between beats is influenced by your autonomic nervous system. In simple terms, HRV reflects the balance between stress drive (sympathetic) and recovery drive (parasympathetic). A stable or improving baseline usually means your system is adapting well to training.

Why athletes track HRV

Readiness: HRV helps decide when to push and when to scale back.
Recovery context: It adds signal to sleep quality, soreness, and mood.
Fatigue management: Multi-day drops often show up before performance crashes.
Planning: It helps guide interval days versus aerobic or recovery days.

How to interpret HRV correctly

Avoid reacting to one low day. Look at a rolling 7 to 14 day trend and pair it with other markers: sleep, resting heart rate, and heart rate recovery. If HRV trends down while resting heart rate trends up, that combination is more actionable than either metric alone.

You can cross-check those companion signals in our resting heart rate tool and heart rate recovery test.

What lowers HRV most often

Sleep restriction and irregular sleep timing
Back-to-back high-intensity sessions without easy days
Alcohol, dehydration, and under-fueling
Acute life stress and travel disruption
Illness onset

A simple HRV decision framework

If HRV is near baseline and you feel good: run the planned session.
If HRV is slightly low for 1 day: reduce intensity but keep volume moderate.
If HRV is low for 2+ days plus poor sleep/fatigue: switch to easy Zone 2 or recovery work.

Use the recovery calculator to standardize this decision process and avoid emotion-driven training calls.

Key Takeaways

HRV is personal. Trends beat raw numbers.
Never interpret HRV in isolation. Pair it with sleep, resting heart rate, and recovery feel.
One low reading is noise. Multi-day drift is signal.
Good HRV use is about better training decisions, not chasing a single number.