WHOOP 4.0 Review 2023 | Is WHOOP Worth It?

The WHOOP 4.0 Strap is an upgrade of the Whoop 3.0. This fitness tracker (released in 2021) boasts an array of advanced features designed to help you optimize your sleep, workouts, and recovery.

In this WHOOP 4.0 review, I’ll explore the features and functionality of this fitness tracker. I will also look at its pros and cons.

From tracking sleep and recovery, and monitoring heart rate variability (HRV), to analyzing workout performance (strain), I will delve into the various features and functions of the Whoop 4.0.

So, if you’re looking for an in-depth review of Whoop 4.0, you’ve come to the right place.

Whoop 4.0 Review

Design and Comfort

The Whoop 4.0 is a small, lightweight device that you wear on your wrist, similar to a fitness tracker or smartwatch – but way smaller and lighter than most smartwatches.

The Whoop 4.0 combines a modern, minimalist design with smart detailing – with new styles released regularly.

This sleek wearable device is made from durable materials and is comfortable to wear for extended periods (designed to be worn throughout the day and night).

Whoop’s SuperKnit bands are soft and flexible making them super comfortable. The bands come in a range of colors and styles allowing you to customize your Whoop.

You can use the Whoop 4.0 with a bicep band if you want to wear it on the biceps.

Activity Tracking

Whoop 4.0 tracks your daily physical activity, including steps taken, calories burned, and active time.

It uses a combination of sensors and algorithms to track movement and provide accurate data on activity levels throughout the day.

Activity Tracking can help you set and achieve daily fitness goals, as well as monitor overall physical activity levels over time.

Strain tracking

Whoop 4.0 Strain quantifies the amount of stress (physical and mental) you are putting on your body.

Stain considers various factors such as heart rate, HRV, and activity level to provide a score on a 0-21 scale. On the scale, 0-9.9 is Light (minimal stress), 10-13.9 is Moderate (Moderate stress), 14-17.9 is High (increased stress) and 18-21 is All Out (significant stress).

The score reflects the overall strain on the body, with higher scores indicating greater levels of exertion.

Strain tracking can be used to monitor the intensity of your workouts and physical activity (Activity Strain), as well as to track your overall daily stress levels (Day Strain).

By monitoring Strain over time, you can optimize your workouts and make adjustments to improve your overall health and fitness.

Under the Strain tab on the Whoop App, you get to see three important metrics: Day Strain, Average Heart Rate, and Calories.

Blood Oxygen Monitoring

Whoop 4.0 measures blood oxygen levels (SpO2) using infrared and red LEDs – alongside an advanced algorithm.

SpO2 tells you the percentage of oxygen in your blood – telling you how well your body is absorbing and distributing oxygen. This is important for the proper functioning of your body cells, tissues, and organs.

Monitoring blood oxygen levels will help you identify potential health problems and make adjustments to improve overall health and wellness.

Blood oxygen levels can be affected by factors such as altitude, exercise intensity, and sleep apnea.

On the Whoop App, the SpO2 is displayed in the health monitor – together with respiratory rate, active heart rate, heart rate variability, and skin temperature.

Resting Heart Rate

Whoop 4.0 Resting Heart Rate is the measure of how fast your heart is beating when you’re resting.

The resting heart rate is typically much lower than the active heart rate. Exercise and physical activities cause the heart to work harder to deliver oxygen and nutrients to the muscles thus a high active heart rate.

Resting Heart Rate (alongside other metrics such as heart rate variability, strain, and recovery) provides you with a comprehensive picture of your overall fitness and performance.

A high resting heart rate (like 100 bpm) can be brought about by emotions, medications, body position, smoking, and cardiovascular diseases.

Heart Rate Variability (HRV) Tracking

The Whoop 4.0 tracks heart rate variability (HRV), which is a measure of the variation in time between heartbeats (RR intervals).

The fitness track uses a combination of sensors and advanced algorithms to accurately track HRV and provide you with actionable insights and recommendations for improving your recovery and performance.

HRV is widely recognized as an indicator of overall health and determines your body’s readiness to perform. A higher HRV score indicates better recovery and is a sign that the nervous system is balanced.

Heart rate variability can be affected by various factors such as stress, exercise, and sleep.

Sleep Tracking

The Whoop 4.0 uses a robust sensor suite to monitor your sleep quantity and quality.

The collected sleep data is analyzed by the app, and you are provided with personalized insights on the different stages of your sleep including REM, light, and deep sleep.

In addition to data on sleep stages, the sleep tracker provides a detailed breakdown of sleep-related metrics such as sleep disturbances and sleep efficiency.

Whoop’s Sleep Coach provides personalized insights on how much sleep you need and when to go to bed.

When you’ve reached optimal recovery, the Sleep Coach can even wake you. To do this, it sends subtle vibrations to Whoop 4.0 which wakes you up without disturbing your partner.

With Sleep Coach’s silent alarm, you can set it to wake up at an exact time, when your sleep goal has been met, or wake up in the green.

The App

Since Whoop 4.0 doesn’t have a screen, you receive all the personalized insights and recommendations via the Whoop app.

The intuitive app (well-designed and easy to navigate) calibrates your data over time and recommends what to do (based on your physiology and goals).

From the app, you can join and create teams. The teams can comprise family, friends, and other like-minded people who will help you stay motivated and accountable. You can chat and share data with teammates.

Water Resistance

The Whoop 4.0 is waterproof up to 10 meters for 2 hours. You can wear the Whoop in most water activities including showering, swimming in chlorinated water, bathing, swimming in saltwater, hand washing, or doing the dishes.

The battery pack for Whoop 4.0 is water-resistant up to 1 meter for 2 hours. This means that you can wirelessly charge the Whoop strap while washing dishes or taking a shower.


  • You cannot use Whoop 4.0 for scuba diving or any form of diving.
  • If you expose Whoop 4.0 to detergents, acids, or nail polish, make sure you wash it with fresh water.
  • The battery pack for Whoop 3.0 is not water resistant and thus should not be exposed to water.

Related: Fitbit Vs WHOOP


The Whoop 4.0 has an impressive battery life – with up to five days of use on a single charge. The strap’s battery life will highly depend on the features you use and charging practices.

The fitness strap also features an efficient charging system that allows users to quickly top up the battery as needed – takes about 2 hours to fully charge the Whoop 4.0 battery pack.

 A fully charged battery pack will charge the Whoop 3.0 or 4.0 fully.

Whoop 4.0 Price

Unlike traditional fitness trackers that are sold as a one-time purchase, the WHOOP 4.0 is offered as a monthly subscription service. Once you become a Whoop member at $30/month, you get the Whoop 4.0 Strap free.

The Whoop membership gives you access to the WHOOP app, which provides personalized insights and recommendations based on your data, as well as the WHOOP 4.0 device itself.

Related: Oura Ring Vs WHOOP

Pros and Cons


  • You get the tracker free. All you pay is membership and you receive hardware free.
  • Anytime a new generation of the Whoop is released, you get it free.
  • The monthly membership gives you access to a full range of features and analyses.
  • The device itself has a simple design with no buttons or screens, and all the data is accessed through the accompanying app.
  • No notifications so no distractions.


WHOOP 4.0 Review 2023
  • The $30/month Whoop membership is a put-off for me. I’d rather pay for a fitness tracker and use it without paying the monthly subscription.
  • You cannot use Whoop 4.0 without a membership. You can use other fitness trackers (like the Oura Ring, the Amazon Halo, and the Fitbit) without membership.
  • Since the tracker doesn’t have a screen, you won’t be able to check your messages, make calls, check your progress on the go, or use other apps on your wearable device. 

NB: The above drawbacks are just minor quibbles in an otherwise excellent fitness tracker that delivers accurate data, intuitive controls, and impressive battery life.

Who is the Whoop 4.0 best suited for?

The Whoop 4.0 is suited for anyone looking to optimize their sleep quality, performance, recovery, and overall health. Perfect for cycling, swimming, golfing, athletics etc

Since the fitness tracker doesn’t have a screen, it is perfect for those that don’t want the distractions that come with notifications.


Overall, I am impressed with the Whoop 4.0 and would recommend it to anyone serious about their fitness and recovery.

While it may not be the most affordable option on the market, its advanced features and personalized analysis make it a valuable tool if you’re looking to optimize your performance, and recovery and improve your overall health.

I hope the WHOOP 4.0 review has helped you make an informed decision. Remember to share the post with your circles.