My friend's Whoop shows much higher HRV than mine. Should I be worried?

No, because HRV is not a competition metric with meaningful interpersonal comparison at the resolution consumer wearables operate at. HRV is highly individualized and varies substantially based on age, body size, parasympathetic tone genetics, medication use, training status, and the specific measurement methodology the device uses. Whoop, Oura, Garmin, and Apple Watch all measure HRV using different algorithms, different timing windows (RMSSD vs. pNN50 vs. other metrics), and different averaging approaches. Comparing numbers across devices is not clinically meaningful.

A 55-year-old man with a healthy HRV of 28 ms on a Whoop, measured on a morning after seven hours of quality sleep, may have a completely normal cardiovascular autonomic profile for his age. A 35-year-old with an HRV of 75 ms on an Oura may have a poorly calibrated device. The question is not "is my number higher than my friend's?" The question is "is my number trending in a consistent direction over eight weeks?" The friend comparison anxiety is one of the most counterproductive patterns in men's wearable health monitoring. (Thayer et al., International Journal of Cardiology, 2010)

Cardiologist's calibrated position, Solid (1) for within-person trend as the only meaningful HRV comparison frame.

What to do: Unfollow or mute social channels where men post their HRV numbers competitively. Track your own 21-day baseline and compare against that. Your HRV is a message from your nervous system to you, not a scoreboard.

For the full picture, read What Your Apple Watch Is Trying to Tell You.