Add Yahoo as a preferred source to see more of our stories on Google. But how did the WHOOP 4.0 stack up when Cosmo put it to the test? From its ease of use to battery life and functionality, we set ...

Whoop's screenless fitness tracker isn't exactly a fitness wearable—it's a collection of subscriptions, with three tiers, each of which comes with a device, either 5.0 or MG. I noticed recently that ...

Beth Skwarecki is Lifehacker’s Senior Health Editor, and holds certifications as a personal trainer and weightlifting coach. She has been writing about health for over 10 years. November 11, 2025 Add ...