New Whoop 4.0 launches – and it can track from your bra or pants

New Whoop wearable can track blood oxygen levels and offer skin temperature data
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Whoop, the company behind the performance-focused wearable favoured by some of the biggest names in the sporting world, has unveiled its next generation tracker. It's called the Whoop 4.0.

The follow-up to the Whoop Strap 3.0, which launched back in 2019, can still be worn inside of a knitted band and still requires a monthly subscription to gain rich sleep, recovery and training insights.

Whoop says its new device is 33% smaller than its predecessor, and now includes a pulse oximeter to monitor blood oxygen levels and a skin temperature sensor. SpO2 is now standard on smartwatches and fitness trackers from the likes of Fitbit, Apple and Samsung.

Temperature tracking, however, is less widely seen – with Fitbit the only major player widely embracing the technology in a meaningful way.

It's also bolstering sleep features with a new sleep coach that uses haptic alerts to wake you up at optimal times based on sleep cycles and sleep time advice.

Quoted battery life is the same 5 days delivered by the Whoop Strap 3.0.

Along with new sensors, the Whoop 4.0 has 'upgraded sensor configurations' which it says should lead to more accurate heart rate measurements. That's good to hear, because despite grabbing a spot in our rundown of the best heart rate monitors, the optical based heart rate monitor on the Whoop Strap 3.0 wasn't 100% accurate or reliable for all exercises we tested it out with.

Essential reading: How Whoop is taking inspiration from Nike

Whoop Body

New Whoop 4.0 launches – and it can track from your bra or pants

We actually found moving it up the arm into the bicep sleeve Whoop additionally offered, improved accuracy. Clearly Whoop has recognized this as well, because the Whoop 4.0 is also joined by a new Body garment range, which will allow you to wear the device in more places around the body.

The Body collection is split into a Training and Initimate ranges, with the former including sports bras, leggings, arm sleeves and shorts. The Intimate range includes boxer shorts and bras.

The Whoop 4.0 is available on the same a month subscription and the new Body garments along with SuperKnit and HydroKnit bands will only work with the new Whoop.

If you're a current Whoop member, you'll have first access to Whoop 4.0 through a free upgrade.

It's been a busy time for Whoop who recently announced it acquired Push, the Canadian startup that launched the Nexus and Push Band wearables designed to help better track weighlifting and CrossFit workouts.

We'll be testing out the new Whoop and some of its new garments to see if this is a wearable you need in your life.

How we test

Michael Sawh


Michael Sawh has been covering the wearable tech industry since the very first Fitbit landed back in 2011. Previously the resident wearable tech expert at Trusted Reviews, he also marshaled the features section of

He also regularly contributed to T3 magazine when they needed someone to talk about fitness trackers, running watches, headphones, tablets, and phones.

Michael writes for GQ, Wired, Coach Mag, Metro, MSN, BBC Focus, Stuff, TechRadar and has made several appearances on the BBC Travel Show to talk all things tech. 

Michael is a lover of all things sports and fitness-tech related, clocking up over 15 marathons and has put in serious hours in the pool all in the name of testing every fitness wearable going. Expect to see him with a minimum of two wearables at any given time.

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