Orthostatic test
Also called orthostatic HRV test, lying-to-standing test, lie-stand test
A short morning test: lie or sit still for 2 minutes, then stand for 2 minutes, recording heart rate and HRV in both positions to see how your body handles standing up.
“Orthostatic” means standing upright. When you stand, blood pools in your legs, and the baroreflex Baroreflex The reflex that steadies blood pressure from beat to beat by changing heart rate. Its built-in delay makes heart rate rise and fall about every 10 seconds, the 0.1 Hz rhythm in LF power. More about Baroreflex eases the vagal brake and presses the accelerator to keep blood flowing to your head. Quigley and colleagues (2024) describe the result: lower vagal and higher sympathetic Sympathetic nervous system The "fight or flight" branch of the autonomic nervous system. It speeds up the heart and makes it pump harder, but it acts too slowly to drive beat-to-beat HRV. More about Sympathetic nervous system firing when standing, with larger differences still against lying down.
The test turns that reflex into a daily check. Polar’s version, for example, uses a chest strap: 2 minutes lying down or sitting relaxed, then 2 minutes standing, each morning after waking, at the same time and in the same position. It reports five numbers: heart rate and RMSSD RMSSD Root mean square of successive differences: an HRV metric built from how much each heartbeat interval differs from the next, in milliseconds. It mainly reflects vagal activity. More about RMSSD at rest, the peak heart rate just after standing, and heart rate and RMSSD standing. Your latest test is compared with your own normal range once you have four or more tests in 28 days.
Why it matters for HRV. Lying down shows the brake at its strongest; standing shows how it responds to a small, repeatable challenge. In a Finnish study of 99 employees, people reporting more stress symptoms had lower HRV in a short lying-and-standing test after waking, while their overnight HRV did not differ (Hynynen and colleagues, 2011). Like any HRV reading, the test only works if you do it the same way every time.
Pick lying, sitting and standing in the model below to see the direction of the change.
Brake and accelerator
A teaching model, not a measurement
- Heart rate
- 60 bpm
- RMSSD
- 58 ms
Set by the sliders below
Lying down. The heart does not have to work against gravity. The brake presses hardest, heart rate is lowest and the gaps between beats vary most.
The sliders and presets work when JavaScript is on.
A heart beats at the rate set by two sliders, one for the vagal brake (parasympathetic) and one for the accelerator (sympathetic). A strip of heartbeats and a line of the gap before each beat show how even the rhythm is. Raising the brake slows the heart and makes the gaps vary more, so RMSSD rises. Raising the accelerator speeds the heart and makes the gaps more even, so RMSSD falls. Buttons set the sliders for lying down, sitting and standing, each with a short explanation: standing eases the brake and presses the accelerator.
Read What is an orthostatic HRV test and should I do one? for the full answer.
Sources
- Orthostatic Test with Grit X Pro/Street X/Vantage V2
- Publication guidelines for human heart rate and heart rate variability studies in psychophysiology—Part 1: Physiological underpinnings and foundations of measurement
- The incidence of stress symptoms and heart rate variability during sleep and orthostatic test