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WHOOP Review 3.0 | Discount – Band 3.0 Strap Specs

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WHOOP Review – the fitness strap – v 3

The WHOOP Review covers a clever training strap that determines the performance and recovery needs of serious-to-pro athletes covering most sports, including cross-training, triathlon & team sports.

Updated for WHOOP STRAP REVIEW 3.0, 15th July 2021

WHOOP’s point of difference from other products is that it provides your readiness to train and sleep needs derived from an HRV view of your ‘recovery‘ coupled with a view of your daily HR ‘strain‘ (activity)

Let’s start with a summary and for those of you that want more, please use the table of contents to skip ahead to the section that most interests you.

This was the first ever Whoop review produced several years ago and it has been continually updated since.

Whoop Review
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Product Name: Whoop Strap

Product Description: Wrist-based heart-rate monitor with recovery and readiness feedback.

Brand: WHOOP

  • Build Quality - 90%
  • Features - 85%
  • Apparent Accuracy - 81%
  • Openness & Connectivity - 81%
  • Price - 83%

Wrist- or arm-worn strap giving athletes readiness & recovery guidance

WHOOP silently does the math that advanced athletes need to know. It combines strain and recovery, through sleep, to give your READINESS TO TRAIN. Which is a KEY metric that athletes need to perform at a high level.

WHOOP also delivers further insights into the trends and deeper analyses of your SLEEP. Whoop’s beauty lies in the clarity and simplicity of the information given to serious athletes about how hard to train and when to train. Most athletes do not have the time to be sports scientists. To arrive at the same answers as WHOOP is a complex process and beyond most of us. Getting those answers correct leads to optimal performances and success, often with straightforward changes to your training and sleeping schedules.

Alternatives to WHOOP include Apple Watch 6, smart rings, Fitbit, HRV apps and some Garmin devices. Here are some headline differences of each type of competitor to WHOOP

  • WHOOP vs Apple Watch 6: WHOOP continually monitors your HR and resting HRV whereas the Apple Watch only takes 2-4 automated HRV SDNN readings per night.
  • WHOOP vs. RINGS: The best ring-based alternative is poor at determining exercise intensity and is effectively only a sleep tracker and not suitable for athletes as their only device.
  • WHOOP vs GARMIN: Garmin devices can be comparable to WHOOP in terms of accuracy but their algorithm provider, Firstbeat, bases many metrics on EPOC studies. Furthermore, the Garmin app simply does not address readiness anywhere near as well as WHOOP does.
  • WHOOP vs. Fitbit: The best Fitbits are great for general, low-level fitness usage and for those who track steps. Fitbits are not for athletes as the sensors and platform are not geared toward you.

WHOOP will suit many kinds of athletic uses where the athlete wants to wear a band outside of sport, during sport and on a 24×7 basis. Even if you are a team sports player then wearing a watch is not going to be allowed during many team sports scenarios, WHOOP’s arm sleeve can be safely worn during team sports.

Key Decisions for  you to make

  1. Will understanding your sleep needs and readiness to train sufficiently justify the subscription price to you? If you are a mid-to-high level athlete you should get some benefits.
  2. Do you want to view accurate heart rates during sport? Like most optical HR devices and like every Garmin watch, WHOOP will not be as accurate as a chest strap.
  3. Will you regularly wear WHOOP at night and during your daily workouts? If not the data and its recommendations will be incomplete.

Key Objections to Overcome

  1. Don’t be fooled by some well-known review sites pointing out the inaccuracy of wrist-based heart rate for workouts. EVERY SINGLE manufacturer suffers from this and WHOOP is no exception. These sites forget to tell you that WHOOP is able to score a workout sufficiently correctly, for readiness calculations and that is all the accuracy Whoop needs. Accuracy is improved and recommended during workouts by wearing away from the wrist using the ARM sleeve.
  2. WHOOP has powerful algorithms to remove noise from the HRV data. Competitors’ algorithms for HRV are highly variable in their accuracy. These algorithms are ABSOLUTELY KEY to getting the resting HRV readings to an accurate enough level to give meaningful readiness and sleep feedback. WHOOP’s is pretty good.



  • Good recovery guidance & sleep analysis from a great app
  • Straightforward band format that’s easy to use
  • More accurate upper-arm/forearm wearing positions options
  • Options to wear during team sports
  • Good algorithms to fine-tune the HRV readings better than some of the competition
  • Many changeable strap designs are available.


  • Variable accuracy as a pure sports HR source
  • Seems expensive but so are competitor products if you factor in a 2-year replacement schedule for a $600 Garmin Fenix

What is it?

It’s a wrist-based optical heart rate monitor made by WHOOP. It has the ability to be worn during swimming and is designed to be worn 24×7. It is sometimes referred to as the WHOOP Bicep Band although it can be worn on the wrist.

It takes continuous/high rates of readings and analyses nightly RR/HRV data.

It has an internal rechargeable battery and a variety of straps can also be purchased.

It has no display and, as of 2019, it does broadcast HR over standard Bluetooth/ANT+ protocols thus, for example, most sports watches and sports apps can connect to it.

For monitoring an exercise, the WHOOP app only has fairly rudimentary information on display but can use your phone’s GPS for speed and location data. Other than GPS, there is no other external sensor support from the app.


The app does also allow numerous, subjective inputs (not used in calculations).

Whoop’s focus is 24×7 strain, recovery and readiness based on HR data and HRV data. The resulting knowledge and insight into your training regime are likely to be currently missing, at least in part, from your training regime.

WHOOP is positioned to sit alongside whatever you currently do. Triathletes’ will still use their existing Suunto/Polar/Garmin devices to execute, monitor and analyse their workouts.

With the WHOOP Strap 3.0 upgrade from 2019, WHOOP will now broadcast HR data to your Garmin, treadmill, bike computer, rowing machine, app and very many other compatible devices via BLE

To see the value in WHOOP you have to understand that, when training, it is the LATER ADAPTATION of your body to the STIMULATION of the exercise that results in a positive change to your fitness. WHOOP endeavours to make sure that you have information to enable you to adapt as best you can. Part of that involves recommending to you the amount of sleep you need ‘tonight’ and also assessing what you actually achieved and benefitted from in your sleep by the time you wake up ‘tomorrow’. It then recommends a level of strain/activity for the day.

What it is NOT

WHOOP Strap 2.0 is not a heart rate monitor that you can link to ANYTHING else. It only works with the WHOOP app on iOS or Android.

WHOOP Strap 3.0 *IS* a heart rate monitor

It’s neither a ‘step counter’ nor a typical activity tracker as such. It does track calories but if that’s the sort of thing you are focused on then WHOOP is probably not for you.

So What?

Maybe I’m not explaining this very well if you are not already excited.

In the original draft of this review I went off on a tangent here to give you my life story and how I tried to find a product such as this a couple of years ago…but couldn’t.

Suffice to say I am excited by the potential of a wrist-based product like this. As far as I know; it is unique.

If your sport requires that you care about your recovery and adaptation to exercise then you should, at least, consider WHOOP.

OK. You’ve got this far. Thank you. I’ll do the regular review stuff now. You will probably have already noted that I’ve sat on the fence quite a bit 😉

WHOOP is priced at around the £/Eur/$30/mo level. As much as I’d love you to buy one of these and support my blog with a small automatic commission that comes from that when you use the discount code, below, I need to do it in good conscience. Luckily I have quite a few gadgets to bring to bear to endeavour to test some of the claims made for WHOOP. I’ve used WHOOP continuously for several months for the original v1 review. This review is based both on that initial usage and many subsequent weeks of use with the V2 and V3 products. I’ve also had several actual and emailed conversations with WHOOP staff.

Box Contents

It’s a nicely presented box that contains: the WHOOP device; an interchangeable strap; a proprietary charging cradle;  a generic micro USB cable; and a carry bag.

Latest 2019 strap is included

The WHOOP Device

The WHOOP Bicep Band has a novel clasp. It’s very light, comfortable and not really noticeable when wearing it. There are no electronic pods inside rubberized straps that can pop out and get lost – like from some other brands.

The strap is highly secure in normal usage

There’s only one way the WHOOP can be inserted into the charger and, as you can see from the images below, the metal ports on the side of the WHOOP need to line up with the pins on the charger for it to charge. You can even charge it whilst wearing it ie the charging cradle retains a charge itself and this is passed to the WHOOP so you do not need the cable plugged into the cradle to charge the WHOOP.



Let’s look at WHOOP’s own-designed sensor array. For comparison, I’ve shown it next to a Scosche BLE/ANT+ armband HR monitor and its sensor array.

There are 2x green photodiode LEDs. That’s similar to many optical sports sensors on the market today, although the Scosche has 3 (2 green, 1 yellow). Apparently green light produces optimal results for most people. WHOOP also has an orange LED but that has not yet been firmware enabled.

Sensor spacing can affect accuracy. WHOOP and Scosche are broadly similar in that respect. In any case, much of the ‘accuracy’ comes from the algorithms that you can’t see.

WHOOP also contains a 3-axis accelerometer that detects activity and the data from this accelerometer is used to cancel motion artefacts (errors caused by moving the wrist).

When you sleep, WHOOP continually takes high-frequency HR readings (100/sec) but only at night are they used to determine the recovery score through heart rate variability (HRV) analyses. HRV analysis potentially could be determined during the day but this is not yet enabled. There are no features that could yet use that facility.

There is a lot of science behind HRV and recovery using the RMSSD calculation.   Alan Couzens blog (here) is a great place to start.

Inbuilt sensors also determine ambient temperature (a proxy for environmental temperature) and there is a touch sensor to determine if the device i.e. being worn or not.

Battery Life

Battery life is given as up to 44 hours ie not quite 2 days. That seemed about right from my experience and I was charging the device every other day, which was fine. Full charge time from empty was said to be about 90 minutes but I found that a good top-up of 30 minutes whilst I was at a desk kept things going nicely. Unusually for wrist devices, both straps and watches, WHOOP can be charged whilst being worn.

LEDs indicate battery life:

I occasionally ran out of battery without realising it. Grrr.

2019 Update: WHOOP Strap 3.0 has an improved battery, lasting almost 5 days

Data Transfer

A full transfer of 2/3 days worth of data over Bluetooth to iOS can take up to 5/6 minutes. That’s fairly slow. That transfer can be initiated manually but happens silently in the background if the app is open and if a live pairing exists. So, although it is fairly slow, you will never normally notice the transfer happening.

WHOOP Versions

The original v1.0 product was released in September 2015. The WHOOP 2.0 was released a year later in Oct/Nov 2016 with the addition of automatic sleep detection; the sleep coach; and more accurate sensors & algorithms.

The v2.0 product is current as of 04 March 2019 however some internal changes were made in 2018 to only enable subscribed devices to work on the platform. Those of you who bought WHOOP before the subscription was introduced should be able to have your device swapped at no cost (and no ongoing cost) for a device that works on the new platform.

The other main update since the initial release is the BAND. The new LIGHTWEAVE band is an improvement on the original.

The WHOOP Strap 3.0 version introduced in May 2019 has a better battery life, broadcasts your HR to other devices, better straps and new coaching features on the app along with the ability to overlap other data onto your workout records.

WHOOP – Why it’s different in how it works

WHOOP can communicate over Bluetooth and now (v3) will broadcast as a ‘normal’ heart rate monitor over Bluetooth in a standard form. This makes it possible for sports watches, other apps and some gym equipment to connect to it and record your HR.

However, WHOOP was designed with the main purpose of being ‘always on’ to capture raw, high-frequency HR data and other sensor data and, generally, sending that for processing on Whoop’s cloud platform. This enables battery conservation for extended periods.

So ALL the processing is either done in the WHOOP app or on the cloud service (and the results passed back to the app).

Contrast that with other commercially available, wrist-based, devices, they perhaps have to: handle ANT+ and BTLE channels; or have to incorporate a display and/or an on/off button; and/or be an activity/sleep tracker, and/or provide smartphone notifications. Lots of other functions, lots of other complications, lots of battery juice eaten.

Setting Up The App

The WHOOP logo to the right clicks through to the WHOOP app on iTunes.

I used version 1.6.3 which works fine on an iPad and v1.1.8-9 on Android

You have to create an account and a profile. You know how to do that; it’s all standard stuff.

You have to pair the device to the iPhone/iPad. Again, you know how to do that, the only special part is to rapidly tap the Whoop to get the white lights flashing to show it is in pairing mode – Bluetooth can be a bit flaky on Android so if you have problems there are special instructions on the Whoop site.

This white light flashes as could the ones on the charger if you are pairing whilst the WHOOP is charging

If you have a Training Peaks (TP) Account then you can authorize WHOOP to send your readiness data to your account on TP.


Here is the v2 manual: WHOOP v2 User Guide – March 20 – 2017 there’s no v3 manual i can find.

Here are setup, wearing & charging instructions: (this link).


You strap it on and you are good to go for about 2 days until the next recharge. Simple.

WHOOP+HYDRO BAND shown worn away from the wrist

Well, of course, it’s NOT quite so simple.

  1. As shown in the image above the wearing position IS important, as it is withevery optical HRM. If you wear it too close to your wrist bone ie closer than shown, then you risk A SIGNIFICANT CHANCE of wrist movements affecting the accuracy of the readings. You could wear it on your upper arm for much more accurate and predictable readings, strap size permitting, but it IS designed to be wrist-worn.
  2. The WHOOP app takes a while to build up your baseline data. Over 3 days. That’s normal for HRV-type apps. Once the baseline kicks in then so do the richness of information from the app.
  3. The app does show battery status but you will likely only look at the app a couple of times a day. You need to remember to charge it every other day. Surprisingly you can charge it while you wear it.
  4. Optical HR readings are notoriously susceptible to many factors causing inaccuracy from hairiness to the colour of your skin to movements. There’s a LOT of movements going on in the wrist area and they’re all potentially subtly different across different sports.

Suffice it to say, you may have a different experience to me.

A dark band was supplied with the model I had and it is fine for every usage EXCEPT swimming when it ‘flips’ and twists leaving the sensor facing outwards. If you intend to swim with it you will need the HYDRO-BAND which is a more rigid woven strap that will stay in place. That’s the white band shown in the previous image.

For those of you involved in contact sports then consider one of the arm sleeves to protect the device as well as your fellow competitors. Wearing the WHOOP Bicep Strap on the bicep is very likely to increase accuracy, I didn’t test that though. (I have tested most other arm worn straps and they are all accurate, the upper arm is the place to wear an optical HR sensor if it’s accuracy you are looking for!)



So that’s all well and good. We’ve got LEDs, sensors and an ‘app’. But most of us want actionable data, presented simply. This is precisely the intention of WHOOP. Let’s see how it does that.

I’m going to look at WHOOP+me. Here’s a bit about me so you know where I’m coming from: I train for TRIATHLON between 40 minutes a day and 5 hours a day, sometimes more. I have managed to average 10-20 hours a week almost every week for years. I sleep between 5 and 8 hours a day. My diet is generally good and I only drink alcohol occasionally and I neither smoke nor take non-prescription drugs. I have a partner. I train for triathlon multi-sports including, occasionally, gym. I would consider myself a decent age-group triathlete. So I am by no means anywhere near a pro-level. BUT I take my training seriously even if nobody else does 😉

I’d say WHOOP is aimed at people similar to me (or athletically better) who consider themselves an athlete of some sort, probably training 7 hours a week or more for a triathlon. WHOOP is looking at giving someone at MY level ‘notable gains’ but much more serious athletes would be looking for the fabled ‘marginal’ gains. Important gains in either case and potentially EASY gains in either case.

For WHOOP to work it automatically records your sleep and automatically records your ‘strain’ (exercise). If you didn’t wear it for the rest of the day its predictive algorithms should still broadly work; although you might be surprised at the impact of the strain of a meeting or the strain of walking to work.

WHOOP is not invasive to your lifestyle. Really, you only need to look at the WHOOP app 2-3 times a day424242

  1. When you wake up – enter qualitative data and review your sleep performance – how recovered and ready for training are you? WHOOP suggests an appropriate level of STRAIN/LOAD for you for the day. Adapt your plan accordingly.
  2. Only if you intend to train a second time during a day might you look at how strained you were after the first session? Adapt your next workout that day accordingly towards WHOOP’s daily strain target for you.
  3. After your last exercise of the day – enter qualitative data about your workouts and WHOOP then determines how much sleep you need to recover. Adapt your evening and night plans accordingly.

Of course you can ignore what it says entirely or look at it more or less frequently.

TRAINING: You CAN use the WHOOP app to show your HR and you can probably record GPS with your smartphone. I never did that. Pointless. You are a vaguely serious athlete, right? WHOOP just slots alongside the Garmin/Polar/Suunto regime you already have (I know as a triathlete that you DO have one!). You want to know how fast your HR is or how fast or powerful you are right now during your training? You look at your normal sports watch. That’s why you bought your normal sports watch. You want to check if you hit those power durations or paces during training? look at Training Peaks/SportTracks/GoldenCheetah, that’s why you have them. Nothing changes! You just wear the strap all the time and very occasionally tap on a few things on the app.

You use WHOOP to recommend SLEEP and to RECOMMEND LOAD/STRAIN. Don’t try to use WHOOP for something it’s not intended for.

The App – A look at all the components in the WHOOP Band Review

I didn’t like the app when I first used it. It seemed basic. But as more data was gathered, so more knowledge and insight was returned. Many of the areas of the screen are multi-functioned so it delivers a little more than you might, at first, think with little snippets of information popping up from time to time about how you are progressing.

I’d personally prefer a rich web interface (there is an online dashboard for trends, I hardly used it) but I’d admit it makes better sense to interact with the app. Shame there is no Android app yet. Grrrr.


Sleep is auto-detected. It does a good job, in my opinion, and seems to correctly identify my sleep durations. I tend to go to bed too tired and fall asleep quickly. Maybe if you sat up in bed reading for an hour you’d fool it. Either way, you can manually over-ride sleep times.

As you can see in the following slide show WHOOP takes some responses to standard questions as well as showing your sleep performance against what it calculated you needed before you went to bed, based on your strain for the previous day. You can ‘drill down’ to look at the sleep stats in a bit more detail.

If you’ve ever used a sleep monitor before you probably found it IS very interesting to look at all the various sleep phases and other stats. But after a while, the novelty wears off. Quantified introspection takes time! Really it’s the actionable data you want ie “you didn’t sleep enough last night” or “sleep 8 hours tonight” and that’s what WHOOP delivers. Simple, actionable stuff.



Activity is NOT auto-detected which is a bit of a faff. For my American readers ‘faff’ means ‘annoying‘!! or perhaps more generously ‘more time consuming than it needs to be‘.

Activity auto-detection was stated by WHOOP to be delivered in early Q2.2017 and that will be a welcome addition.

You can either manually assign a sport type to an already-completed activity period or press ‘start’ and ‘stop’ before and after selecting a workout type.

So in this image, I had 78% of the sleep I needed; delivering only 38% recovery. I woke at 9:00 am and then I had a swim from 10:30 to 12:00 (not auto-detected).

So, in this case, I manually added a swimming activity over the HR track giving start & end times as well as adding qualitative impressions about how I felt I performed. These qualitative data are not used to determine any component of ‘strain’. I would, however, have hoped for an estimated figure for strain in the scenario where no HR data was gathered eg ‘flat battery’ or eg ‘forgot to wear’.

WHOOP identifies the strain automatically. It just doesn’t automatically ask you to assign it to a sport. You do NOT NEED to assign it.

Anyway, you enter your exercise parameters and WHOOP goes off and calculates AND SHOWS your workout strain score; in this case, coming back with 11.5/21 By the end of the day you can see a very, very slightly higher strain of 11.9.

This is actually a nice example for other reasons. There are some peaks around 6:00 pm that are probably false and also slightly raised HR at around 9 pm. But they make little or no material difference on the daily strain IMO. I’ve seen some comments on the net about users taking issue with the unexpected peaks. Yes the peaks are probably wrong but what’s important is the area under the curve, that is (sort of) the training load/strain. There is virtually no ‘area’ underneath those peaks so their effect is highly likely to be trivial.

Two possible downsides for triathletes in the calculation of strain are:

  1. WHOOP calculates strain (training load) from HRmax and the day’s HRrest. Creating zones based on the HRreserve. It’s neat that a varying HRrest is used but many triathletes and Garmin users are becoming used to setting zones based on the AnT/LTHR (Lactate Threshold Heart Rate – strictly the LT Turnpoint)
  2. Furthermore, some athletes use different Ant/LTHR for each sport resulting in potentially very different zones. So the 140-150bpm, or thereabouts in the above chart is probably Z4 for me when swimming but for running the same HR level would be Z2.

Whilst those factors, even if included, might not make too much of a difference I would expect that most data-orientated triathletes would expect to be able to define their own training zones. Against that WHOOP might, in part, argue that such training zones are static and are inaccurate as they do not reflect changes to your resting HR. Which IS a good point?

Indeed on this point WHOOP specifically asked before publication that I include the fact that they initially determine HR zones based on clustering algorithms (which include age) and that their algorithms refine the data over time, with usage.

WHOOP Review – APP Trends/Summaries

Trends are not shown on the app as such (see the online dashboard part of the WHOOP review). However there is a limited, but useful, calendar view where each type of measurement is shown, colour-coded, for each day of the month.

The most interesting view, from my perspective, was the ‘Readiness’ view. In the examples shown below, I am following the same training structure each week with Monday as a rest day and Tuesday PLUS one weekend day as hard days.

Clearly, the images below show that on most Wednesdays I had a low readiness (red). Tuesdays was always a fairly long run and a hard evening swim. Perhaps suggesting that I should either: train easier on Tuesdays (probably not, as I performed well in the swim); or that I should take it easier than what I did in Wednesday’s Brick training where I did often feel tired; or to improve recovery by actually following what the sleep coach suggested I should have done and got at least one hour more sleep on Tuesday night! Probably the latter!

Regardless of whether or not I made the correct training decision, WHOOP’s views of my training and of my recovery seemed to quantify how I felt.

WHOOP Review – Online Dashboard

There is also some additional, albeit limited, trending functionality online. The colour-coded red/yellow/green recovery line is plotted against the blue-only strain/load line. Maybe I should have been performing high load workouts on days of green recovery?…maybe. Conversely, my load/strain should have been low on the days of the 5 red dots. They weren’t.

Maybe I made some bad decisions? It is sometimes easier to rigidly follow a plan. Doing less training feels intuitively wrong.

But we probably know in our hearts that it is better to sometimes ease off. WHOOP gives you that information. Ignore it or follow it. It’s your call.


I consider myself to be reasonably aware of my sleep quality and very aware of my training load. I’ve used several disparate tools to measure those over the years.

So, I wasn’t really expecting to learn too much.

However WHOOP’s recommendations for the amount of sleep I needed were eye-opening. Routinely I was 2 hours short of my recommended sleep each night. I have managed to get that down to one hour and I even scored a 100% sleep on one night (just one!). But I then do feel better for that extra sleep. Kinda stating the obvious. But so obvious I haven’t done it for years.

The other main insight comes with alcohol consumption. There have been a few occasions when I have consumed relatively small amounts of alcohol but then the next day the recovery shown on WHOOP is very small. Again it’s stating the obvious that Olympic athletes are not prescribed alcohol during training for a reason. It’s not great for athletic performance. Seeing that with your own data can be a game-changer.



So all that looks great. But how accurate is it? Indeed what is accuracy in this context?

PLEASE!!: I have to point out that I am not claiming any kind of scientific accuracy in my ‘tests’.

I have over 50 sessions’ worth of data with WHOOP alongside ‘something else’ and have taken them into account when producing this WHOOP Review. Many of my training sessions had similar results and I chose a few, below, that seemed representative of different types of training and asked WHOOP for the HR data. It was very time-consuming to put all this together but I think the results are worth it.

I’ve endeavoured to cover the normal range of my exercise-based heart rates; that’s from 120-170bpm or thereabouts. I’ve done that over the three triathlon sports and, where possible, I’ve tried to compare to two other devices one being an alternative source of optically derived HR. For the higher levels of exertion in intervals, I’ve also included different types of recovery activity (standing vs. jogging vs. Z2).

WHOOP was kind enough to send me CSV files of the raw data and Matthias Krallmann, publisher of what I consider to be the ‘gold standard’ of sports file data conversions helped to get the data into FIT format that I then performed comparison using SportTracks desktop (data conversion with the Fit File Repair Tool).

Here’s the first example comprising: Scosche (optical armband) paired with the Lezyne; Suunto SPARTAN and Suunto chest strap; and the Polar M200 with inbuilt optical HR. For this ‘test’ the WHOOP was also worn on the upper arm like the Scosche (it’s an easier place to get better readings than the wrist).

Two things to ignore: Firstly I wore the WHOOP to run to the starting point of my test, that’s the bump at the start. Secondly, the Polar tails off at 1 hour 20, that’s just because I fiddled with it.

Clearly, visually, there is a great deal of tracking between the four lots of data for the test period between 20:00 and 1:45:00

The following chart is for a more demanding session with a mile of fairly hard effort leading into 3x 1 minute fast with different kinds of recoveries. WHOOP didn’t track quite so well here. We’ll come back to the interpretation later.

Cycling poses issues around filtering out the ‘noise’ caused by movements of both the wrist in different riding positions as well as vibrations from the road surface. WHOOP and Polar both suffered here for short bursts but over 3 hours of Z2/Z3 yet both broadly tracked the Suunto. You can consider the Suunto to be ‘correct’.

Swimming is not supported by many of the optical HR sensors. Indeed up until 2017, Garmin did not enable optical HR for swimming on any device. I’ve found that Polar’s M200 or M600 either perform very well in water OR have a ‘bad day’, The following image is a good day for the M200 as I tracked through varying intensities and cadences of front crawl for 20 minutes or so. The green line is the WHOOP this time and, again, assume the Suunto is correct.



Further test using the app for indoor cycling: I used the WHOOP app to get a feel for the ‘live’ HR and how it visually compared to the instant HR from my Garmin. There were some notable, short spikes with the WHOOP. Generally, it seemed ‘about right’.

Whoop Review ACCURACY – what does accurate mean?

I showed another set of my data to WHOOP and their feedback on the variation to the WHOOP data was that it was: “it’s consistent enough throughout such that our Strain and rest of the system will be able to identify the important physiological aspects of the workout.” Source: JC, WHOOP.

Edit: along with dcrainmaker and others I have looked at the broadcast accuracy of the HR from the Whoop Strap 3.0

My ‘take’ in this WHOOP Review is that: they believe they are getting the ‘time-in-zone’ correct enough to meaningfully record strain/training load.

Our sceptical view might be: “Well they would say that, wouldn’t they?” Let’s look at that too…

ACCURACY – A ‘truer’ measure?

TRIMP is a heart rate measure of your training load and is a well-established principle in endurance sports (link to It quantifies the effect of the time spent in each training zone, giving a higher weighting to time spent in a higher zone.

So here is what SportTracks calculated the training load to be. The load is based on TRIMP. These are the TRIMP scores from some of the examples shown above and they are HIGHLY SIMILAR – any variation of a couple of TRIMP points is NOT material.

That looks reasonable to me.

If you bought WHOOP and solely wanted to use it as an instantaneous source of HR for your sport then there are definitely LOTS of better solutions out that for that purpose. You probably already have one with the word Garmin written on it!

I am the first to admit my tests are rudimentary and non-scientific. If you wanted to conduct a scientific experiment to validate WHOOP then my suggestion would be to try to validate the ‘overall usefulness’ through a measure of training load/strain like TRIMP.

Initially, I was concerned about some of WHOOP’s HR spikes when viewed live. However, after looking at the training load calculations, such as those shown above, my view changed to becoming generally happy with what WHOOP does on the STRAIN side of its calculations.


Really we are trying to measure the accuracy of RECOVERY not sleep.

First of all, put aside your Fitbits and your Garmin wrist bands. They either measure motion or simple HR and try to infer a LOT from those simple measurements. Most of them probably infer an AWFUL lot.

A simple HRrest/HRmin in the morning might generally have some value in indicating recovery. Might. Let’s leave it at that.

Here is two nights’ worth of my sleep with a simple HR chart plotted for each night comparing EMFIT to WHOOP. I’m certainly NOT implying EMFIT is the gold standard for medical-grade night-HR accuracy.

The general HR trend for both nights with the two devices seems similar enough.

BUT that is nothing to do with HRV.

I buy into the broad argument that a rising trend in RMSSD throughout the night indicates a positive recovery/adaptation. RMSSD is calculated from the beat-to-beat variation of your HR ie HRV/IB/RR – whatever you want to call it.

The key thing that WHOOP has that your Garmin lacks is that it can measure your HRV at night from your wrist without the need for a chest strap.

I can’t sleep with a chest strap and years ago I used to use a 3-minute waking HRV measurement in the morning from a chest strap. this takes up a lot of time over the year and I eventually moved to QS EMFIT which involves a sensitive metal strip underneath a mattress to measure all-night HRV.

EMFIT produces an rMSSD calculation of my night’s HRV data. It then plots a line of best fit. voila. It should then look something like this:

12 March 2017-A good night’s sleep with QS.EMFIT


WHOOP did provide me with beat-by-beat data to perform my own RMSSD calculations but I was unable to import it.

So I am somewhat of a dead-end for that line of investigation for the time being. Sorry.

What I do have, however, are these two overviews of trending RMSSD in February – one from EMFIT and one from WHOOP. EMFIT has a very slick interface and feels more accurate and there is more depth on analysis of the data.

However, I KNOW that on Wednesday morning of each week I was very tired from two multi-sports workouts each and every Tuesday. The red dots on the chart, below, from WHOOP, identify nearly all of these ‘tired’ Wednesdays. WHOOP also identify that Mondays were my day off in this time period, EMFIT does not measure strain/training load in any way. So whilst EMFIT might be a slicker interface, WHOOP does seem to correctly identify some key weekly moments in my training that push me somewhere close to ‘the edge’.

EMFIT – RMSSD Recovery – Proprietary Measure over Feb 2017
WHOOP – Coloured Dotted Plot IS Recovery


Pondering over WHOOP’s recovery stats I’m erring towards feeling that it’s ‘about right’.

RESEARCH: (Here) are some of WHOOP’s validations and white papers


Others could argue that better integration with the existing sports data sources like Garmin/Polar would be useful. I would disagree with that. WHOOP needs to keep its focus on doing what it does.

Others would argue that WHOOP should broadcast or make available HR data.


WHOOP is a uniquely successful product. No other product does quite the same thing in quite the same way at least that’s what I found from my research for this Whoop Review. Thus most of the alternatives to WHOOP are looking at some of the aspects that WHOOP covers from a different perspective or taking certain aspects and providing lots of detail (that most people are not too interested in).

  1. EMFIT – is an athlete-grade sleep tracker. It does not attempt to measure your strain and indeed can’t as you put it under your mattress!
  2. Biostrap – is perhaps the most similar to WHOOP. It presents greater details on SLEEP but is coming at the market more from the needs of someone who has a medically-related sleep issue and who REALLY wants to understand their sleep and sleep-movements.
  3. Garmin, etc – Sports watches from Garmin, Polar and Co will do a much better job of tracking in detail your sporting endeavours and they assess your readiness by modelling your ACTIVITY, perhaps only partly taking into account the recovery piece from your sleep. Invariably they have complex ecosystems and sometimes lack the ability to give clear guidance.

Whoop vs RING Products

A lot of people see Whoop and RING Products as alternatives but, to me, they sit in a totally different category despite some similarities. RING’s strengths is its detailed sleep analysis and guidance. RINGs are not as good as WHOOP on the ACTIVITY piece, Whoop does not provide the detailed SLEEP insights that you get from some RING products

Those are the headline differences but clearly also the format of RINGs compared to Whoop is different.

If you consider yourself to be an athlete then the Ring products are not adequate, as your only tech product, is not for you.

MISC points in the WHOOP Review

WHOOP is also available as a TEAM solution.


It’s a neat product concept. I wanted EXACTLY this product 5, or so, years ago. But it didn’t exist.

Now it does! It has no clear and direct competitors for a wrist-based measuring solution that offers athletes straightforward training guidance.

WHOOP bridges the gap that the likes of waking HRV products like ithlete and BioforceHRV; and non-intrusive HRV sleep monitors like Beddit and QS EMFIT, do not yet fill. In that WHOOP provides a combined picture of recovery and strain. Rather than just one side of the picture. AND WHOOP provides that insight through a non-intrusive wrist-wearable.

In my opinion WHOOP does seem to be guiding me in the right direction towards how hard/long I should be training and how long I should be sleeping.

The sensor readings do show incorrect HR spikes from time to time during the day. I attribute this to either me incorrectly wearing the device and/or how WHOOP handles motion artefacts such as a twisted wrist on a bike on a bumpy road.

I’ve looked at my trainingload calculations based on HR on a near-daily basis for almost 10 years. The spikes from WHOOP are rarely long enough to have affected the overall load calculation from what I can see. The resultant score or recommendation would likely be little-changed even with perfect data. As to whether or not the recommendation is scientifically ‘correct’ and well founded, then “I don’t know”.

Yet many of us have looked at HR spikes on our Garmin (and other) running watches with optical sensors and bemoaned their inaccuracy. I’d suggest that is a slightly different use-case. When you are running hard for a minute then you want an accurate figure for that minute. It DOES matter to you when you are training and WOULD make you do something different if you believed the data. That minute won’t make much of a difference to what WHOOP does. BUT that will be of no comfort for those amongst you who expect a 99.9% accurate product all the time. If that’s what you want then don’t buy the product.

If you want an easy-to-wear holistic solution for recovery/strain measurements and recommendations then I can see no single product offering a real alternative to WHOOP.



WHOOP have changed their pricing model and they now have a monthly charge. IT IS NOT POSSIBLE TO PURCHASE THE BAND, INSTEAD, YOU HAVE TO SIGN UP FOR THE SERVICE.

US$30/month, minimum 6 months that’s $180, less the 10% WHOOP discount & promo code from hereFree signup here! Join WHOOP

in the EU please use the slightly different code: the5krunner10eu




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