WHOOP. 2 people have talked about it publicly.
Greenfield says he tracks himself with a WHOOP strap; the episode was hosted by WHOOP's Will Ahmed and the page offers a discount code, so there is a commercial link.
“Whoop strap (use BEN for a $30 discount)”Ben Greenfield
Source: A Day In The Life Of Ben Greenfield: Ben's Exact Morning, Afternoon & Evening Routines (podcast, 19 Oct 2019)
Used to track HRV and recovery.
He said he wears a WHOOP strap to monitor his heart-rate variability and recovery.
“I've got a WHOOP Strap on that will tell me my HRV and my recovery and all of that sort of stuff.”Chris Williamson
Source: Morning Fitness, Optimizing Hydration, Screentime Management, Sleep Tips, Cognitive Biases & Other Uber-Helpful Life Hacks With Modern Wisdom's Chris Williamson (Ben Greenfield Life transcript) (podcast, 5 May 2022)
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