"HRV is the measurement of the variation in time between consecutive heartbeats, also known as the R-R interval. It provides information about the balance between the sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) branches of the autonomic nervous system."

"Orthostatic measurements (or vital signs) are blood pressure and heart rate taken while lying down, then again while standing (or sitting) to diagnose postural hypotension or tachycardia" Google AI "An orthostatic test (lying-to-standing) combined with Heart Rate Variability (HRV) monitoring assesses autonomic nervous system balance, helping to track fatigue, training readiness, and recovery"

"When it comes to monitoring individual athletes, “normal” variations in the measures (e.g., within-athlete day-to-day variability, as measured by the typical error, TE, expressed as a coefficient of variation, CV) is the primary variable to consider (Hopkins, 2000a). The variability in each measure can be obtained either from the literature, or from repeated data collected in your own athletes (Hopkins, 2004). The magnitude of these variations depends both on the HR variable and the recording conditions (CV range: 3–190%, Table 1) (Sandercock et al., 2005)."

Protocol (takes ~5 minutes):

Athlete lies down for 2-3 minutes → record heart rate/HRV

They stand up

Record the response over the next 2-3 minutes

Tools you can use:

Chest strap (Polar H10) + an app like HRV4Training or Kubios — most accurate

Fingertip pulse oximeter — cheaper, less accurate

Smartwatch (Garmin, Whoop, Oura Ring) — convenient but varies in accuracy

What you're looking at:

How much does heart rate spike on standing?

How quickly does it settle back down?

A slow, sluggish response = poor recovery

Practically with a team:

Do it every morning before training, same time each day

Log it consistently — trends matter more than single readings

Some teams use apps that flag athletes who show concerning patterns so coaches can adjust their training load

For recovery, post exercise HRR is an sign of recovery, depending if it is increasing or decreasing