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[2021] Biostrap EVO Review vs Whoop Band 4

Biostrap Review
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Biostrap EVO Review, Gen 2

I was convinced to write a Biostrap EVO Review by a STRAVA 3rd party App developer who was integrating Biostrap’s data into some complex performance algorithms for In his considered and technical opinion, Biostrap was ‘Very Cool‘. I don’t always take ‘Very Cool’ as a recommendation but MW@STRIVE knows his stuff so I decided to invest some time in a review to check out what Biostrap EVO is all about. I was impressed.

Biostrap EVO Review Updated: 24 November 2021

First up – we are NOT talking about a cheap $30 step tracker. Biostrap is in a WHOLE different ballpark to those basic products.

Let’s start with a brief summary and following that is the detailed review. If you just came here for the 10% discount and a free 6-month subscription to the premium Biostrap services then use code THE5KRUNNER at checkout to get 10% and use this link to get the free subscription period.

In Brief
Biostrap Review

Product Name: Biostrap EVO

Product Description: Activity Tracking Solution With Several add-on feature packages and sensors

Brand: Biostrap

  • Features - 95%
  • Price - 75%
  • Apparent Accuracy - 90%
  • Battery Life - 80%
  • App & Hardware Design - 80%

Wrist-based DEEP Activity Tracker

Biostrap EVO offers a cheaper and more realistic alternative to the popular and trendy WHOOP Strap 4.0 but with EVEN MORE features. What sets Biostrap EVO apart from all other products in this review are the detailed analyses for sleep; HRV & SpO2 sensing; strength & conditioning learned activities; footpod for unique sleep insights (and running/cycling stats); team & family data sharing; and the report facilities to help monitor some chronic medical conditions.


  • Great app experience
  • Recovery – Readiness score similar to Whoop and other HRV apps
  • Impressive breadth & Depth of Insights given
  • Biggest 10% Biostrap discount and free subscriptions with code THE5KRUNNER
  • Sound workout tracking – a great S&C option
  • HR, HRV, Breathing and SpO2 all-day tracking
  • Sleep & Pulse reports are designed to be printed out to show your doctor
  • Aeroplane mode recently added, can be used anytime
  • Family/Team sharing functionality
  • Sensible price


  • Aesthetic Design
  • Battery life is alright but only up to 3 days
  • Extra pods add accuracy but the fact they are separate is necessary but annoying at the same time
  • Android sync times
  • Body temperature sensor would have been nice

What Is Biostrap?

Biostrap EVO is a detailed sleep monitor, activity tracker, running analysis tool and meditation guide all rolled into one. It becomes a little complicated when explaining all the available hardware add-on options and software add-ons, yet the basic Biostrap is simply a wrist-worn heart rate monitor. Even that description somewhat fails to explain some of the unusual and cool stuff offered by Biostrap. Let’s start off with the red light sensor on the strap that measures BLOOD Oxygen (SpO2) this feeds into some pseudo-medical uses that I’ll cover later and also let’s point out the HRV analyses at resting levels of HR that are also included. IE there is potentially LOTS of cool stuff.

Perhaps this chart will give you a flavour of some of what’s on offer.

Q: Who Might Buy Biostrap EVO?

A: Lots of people. In a way, Biostrap EVO will appeal to even more market segments than Biostrap currently target. But currently, Biostrap targets these types of consumer

Polar A360, Biostrap, TomTom Touch

Biostrap EVO reminds me of WHOOP, which some of my regular readers might know about. Biostrap EVO does NOT YET do the ‘recovery’ piece as well as WHOOP (Review) but instead delivers extra SLEEP insights along the lines of ORA RING and MUCH MORE besides SLEEP.

Anyway, there’s a LOT to say so let’s continue from here in a more structured way. You can skip forward to the sections that most interest you.

Biostrap EVO Review Product Options

The physical products and accessories are

The MARKETPLACE section of the app allows you to upgrade the app with additional functionality. These additional areas of functionality are bought on a per month subscription basis and more could be available in the future.

I’m reviewing the whole lot but please be aware that the apps require an additional, ongoing cost and that the ELITE RUNNER package is only just being released now.

Unboxing and Contents

With the Total Health Set, you get an induction charger for the included pod and wristband. The wristband itself has a total of three interchangeable straps that are also included whereas the footpod comes with a clip to fasten on to your laces. The ankle strap (not included in this Biostrap EVO Review version) would be used for the footpod during sleep to track your leg movements and possibly also when cycling.

Cradle, included, but not shown

There’s bits of paper and a USB cable…you know, the usual drill.

Wearability & Usability

In general, I like the wrist band format however I’m not so keen on the straps that Biostrap provide. They can be tricky to get sufficiently tight and my preference would be for a strap akin to a traditional strap on a wristwatch. That said, the Biostrap is light and easily worn without having to worry about it or particularly be aware of it.

The physical dimensions of the product seem standard for this format of a fitness wearable. However, I would point out that the Biostrap is over 10mm deep and when I was wearing it in winter sports usage UNDERNEATH FULL-LENGTH ARM WARMERS, I experienced a little discomfort as it was pushed into my skin but, for the rest of the time, wearability was great.

Biostrap Footpod compared to Garmin equivalent

The footpod comes with a nicely fitting cradle which attaches to running shoes easily and securely. However, it is supposed to also provide cycling cadence and yet the cradle would not span the velcro straps of ANY of my cycling shoes.

The footpod is super-light and I would guess that if you wore it with an ankle strap at night you would not notice it.

Other than that I would have liked a battery that lasted longer than two days but if it DID last three days I guess I’d want more than that.

The app is great overall and intuitive to use. I tended to use the Android version and was generally impressed with what was presented – I’ll cover that in more detail in a minute but the only general negative experience I had with the app was that it was relatively slow to pair and sync data. In Biostrap’s defence, maybe they collect too much data 😉 and there is an option to reduce some elements of the data collected.

SetUp and Constraints

Setting everything up is ‘normal’ and just like creating an account on many other apps. Physically pairing the footpod and wrist band to the app is accomplished from within the app and no other configuration is required. It’s just pair-and-go.

There is one thing that is very important to mention here. And it’s super important.

Biostrap also gives you the option to pair to a heart rate monitor. “WHAT?!?”, you say. “Why on earth would it do that when it is already a heart rate monitor?”

This might seem crazy…but really, it’s not. Trust me. It’s almost a stroke of genius.

You can read very many sports watch reviews on this site or perhaps check some of the forums. You will see a common thread that a significant number of people do not get accurate heart rate readings from wrist-based sensors WHILST EXERCISING RIGOROUSLY. Put another way if Biostrap used their optical sensor for sports it will likely produce incorrect data just like EVERYONE ELSE’s wrist-based optical HR (at least it would for some people). These errors are partly linked to the technology but mostly it’s just that some people have the wrong type of physiology such as hairy, dark skin or poor circulation and that the wrist is an AWFUL place to measure heart rate optically. It’s technically VERY difficult. Anyway, Biostrap recognises this and give you the option to use a chest-HRM or upper arm HRM…I used the Polar OH1 but only whilst exercising. Using a HRM for sports gives the Biostrap app accurate HR for its in-sport calculations (I’d recommend you do that).

Biostrap Specifications

Some points:

Biostrap – Sensor & General Connectivity

Science, Accuracy & Product Claims

Biostrap produce validation studies which are linked to here on

If you are contemplating buying Biostrap because of atrial fibrillation (AF) then you might want to see if those studies are OK for your precise needs. I am NOT making any medical-grade claims for Biostrap but Biostrap do publish comments from Doctors in the USA who recommend their product to patients.

Biostrap measures SpO2. This is the %age of oxygenated blood you have. Mine is usually 99/100% and sometimes as low as 97%. If yours is below 95% I would go and see a doctor if I were you. SpO2 is NOT muscle oxygen and is not an especially useful measure for athletes when exercising. It might be worth watching if you are at altitude thus, mostly, SpO2 monitoring is going to be of interest to people with medical conditions.

Some of Biostrap’s validation studies also point to the measurement of Heart Rate Variability (HRV) – which you might also see referred to alongside these terms IB, RR, RMSSD. HRV, in my opinion, is a good measure of combined physical and mental stress. Biostrap’s measurement of HRV can only be accurate at resting levels and the best time to take these readings manually is when you wake up and when you go to bed. Biostrap also takes these readings periodically throughout the day.

In my opinion, HRV should be of interest to everyone, including athletes and its only main downside is that it cannot distinguish between physical stress (eg from exercise) and mental stress (eg from your boss). It is NOT snake oil, there is proper science here and HRV is definitely worth a google if you want to learn more about it.

Variation in your heart’s waveform can indicate when a breath is taken, hence HRV can be used to accurately determine your respiratory rate… #Cool!

Note: I normally endeavour to try to validate the manufacturer data. I’ve not been able to do that with Biostrap. Most of the data is not that hard to capture correctly, it’s more what Biostrap do with the data that adds value to the offering.

Biostrap EVO Review – App & Dashboard

The dashboard is the main place for all of your Biostrap data. For each day you can see high-level metrics for 8 key measures like this…

Like most dashboards, this gives a good overview to quickly and visually see if there is anything untoward going on with your physiology and then you can drill down into the detail.

Let’s look at those aspects of physiology in more detail and how they are presented in the app.

Note: The dashboard aesthetics will be changing soon

Biostrap App – Steps

This section has the usual kind of details, with steps ranging from a summary throughout the day (including running) through to monthly/yearly trends. I’ve shown the daily trends throughout a recent week, below.


Biostrap App – Sleep

Biostrap AUTO-detects sleep and you can also manually start your sleep time, I tended to do the latter.

The app gets SIGNIFICANTLY more interesting on the sleep piece which has some impressive insights. This is one long screen which you scroll through and I’ve shown images from a progressive scrolling, below

The overall sleep score seemed to me to be a reasonably good indicator that tallied with my feeling of how good a night’s sleep I had. In the example shown I scored 97% and had an excellent night’s sleep, typically I would say I sleep relatively poorly and the scores are often much lower. FYI: As a comparison, another SLEEP tool I use called EMFIT scored the same night at 84% but the two systems use different scoring algorithms.

There is a daily survey for you to answer the question “How are you feeling?” and then your responses are tagged and shown against each night’s history. This is just for the record and cannot be analysed in any other way AFAIK.

The first element of sleep data we come to is the SLEEP STAGES. I’ve again compared Biostrap’s SLEEP STAGE data to that from EMFIT for the same night. I’m not saying that either of them is right or wrong. They have similarities but are notably different. eg The overall time in each stage for Biostrap is

Looking at the details of the sleep stages over the entire night when compared to EMFIT you can spot similarities in the night’s pattern.

I have looked at several consumer-SLEEP STAGE tools and they seem to ALL disagree with each other. Putting that unfortunate truth to one side, I would still say it would be reasonable for you to look at the sleep stage data from one particular tool over time and see how your sleep stages trend and react to other factors. But I would NOT take ANY vendor’s sleep stage information to discuss with your doctor.

On the other hand, the rest of the Biostrap’s SLEEP data is probably reliable. For the night in question, Biostrap has my resting heart rate (HRrest) peaking at 67bpm and falling to 48bpm.

HRrest and SpO2

Withings, Fitbit, and others, including Biostrap, have SpO2 sensors in their wrist-based devices to measure blood oxygen saturation (SpO2). Low SpO2 can be associated with chronic obstructive pulmonary disease (COPD), asthma, pneumonia, anaemia, heart attack or heart failure and congenital heart defects. Please do not infer that you have any of these conditions from a low SpO2 reading. The value of monitoring SpO2 may come as part of casual, post-diagnosis monitoring of less serious conditions.

I like the clarity of Biostrap’s graphs and the following one covering nightly DISTURBANCES is also great. I was only wearing the wrist band to get these movements but had I worn the foot pod with an ankle strap it would have given me a similar, additional chart. This leg movement data is unique and I have not seen it available in any other consumer-level tool. Leg and arm movements can be associated with poor sleep and conditions such as nocturnal myoclonus.

Another thing worth pointing out is that the previous charts line up disturbances and biometrics underneath the sleep stages, so you can visually see at which sleep stage the events are happening. There are also some summary numbers at the end of the app’s nightly SLEEP section.

Sleep stage data is also shown trended over time as are sleep score, SpO2, calories and breaths/min… #Cool

Another cool feature is that Biostrap will email you a sleep report in pdf format. I suspect the purpose of this is to share with your medical professional.

Part of the Sleep report


Sleep Lab

Some of the Biostrap’s SLEEP functionality is via an additional paid-for module called SLEEP LAB

SLEEP LAB boosts Biostrap to produce one biometric scan every 2 minutes so producing more detailed data for heart rate, heart rate variability, oxygen saturation, and respiratory rate. It also adds in arm and leg movements (if each sensor is worn) and reports them as ‘disturbances’.

I tried to test out the SNORING feature by leaving my smartphone next to the bed and recording but I guess I am snore-free.

Biostrap is the only consumer-grade sleep tracker that looks at leg movements. Biostrap asked me to highlight that many of their users use Biostrap as a sleep disturbance screening tool to monitor Restless Leg, PLMD, and REM Sleep Behavior Disorder.

Biostrap App – Resting HR

Resting HR (HRrest) is always worth at least a casual glance even from more serious athletes. Your HRrest will trend lower if you are ‘fitter’ and might be above your baseline if you are fatigued.

We’ve already seen HRrest included in the overnight sleep piece of the Biostrap app. With the Resting Heart Rate section, there are 24×7 readings as well as day/week/month trends.


Biostrap App – Heart Rate Variability (HRV)

Link to: HRV Science

You might see the terms RR or IB which refer to the time between each of your heartbeats. Well. These time periods vary continuously depending on the state of your nervous systems. The more variability there is between heartbeats, then the BETTER it normally is. This variability is measured statistically using a technique called rMSSD but it’s probably best just to think about it as “high HRV is good” – a counterexample is the high HRV which could be associated with AF.

Some of the following charts show that my HRV is currently low and I put that down to some minor muscular/nervous issues that I have coupled with an unhealthy dose of ‘training too much’. A lowered HRV can be due to such factors but also such things as work-related stress. If you think the latter affects you then it could also be useful to monitor blood pressure – I do that occasionally and my BP has generally lowered over the last few years.

Biostrap does some nice presentations of your HRV data along the same lines as some of the other measures, like this…

One good thing to look out for is the short yellow line in the first of the images. This shows the rise in HRV as you sleep. It is thought that the body physically repairs itself overnight in non-REM sleep. I’ve already said that the sleep stage analyses by any app are not truly reliable and so you cannot really infer muscular adaptation from the time spent in the app’s definition of non-REM sleep. However, I WOULD say that HRV IS MOSTLY RELIABLE at showing, crudely, increased overnight fitness/adaptation. Thus the upward-pointing yellow line literally could show how much fitter I got overnight.

I spent MONTHS looking at my daily HRV changes several years ago and it can become distracting as well as interesting. I’ve since kicked that particular habit but one thing I did realise in hindsight was that I was focussing too much on what was happening overnight – one night it was good and the next night…not so good. But I lost sight of the trend. Looking back at my 2018 training for IMUK, I significantly and progressively ramped up my training load from January through to the Summer. At the time I never noticed that my average, weekly HRV very gradually and progressively fell. Even though I followed a taper, my HRV did NOT subsequently recover to the levels at the start of the year in time for the race. It seems logical to me that HRV should have returned to those levels, so maybe that could explain a sub-optimal performance?

The point remains that HRV is a great insight into what is happening in your body and there are very important short-term and long-term events to keep an eye on whether you are an athlete or just have an interest in your inner self.

Biostrap App – Time Out

Thank you for reading this far in this Biostrap EVO Review.

Most of the sections I have so far covered so far in the app are available elsewhere with other products (but a few are not).

However, Biostrap offers even more tracking and insight that does make it a unique overall offering. Let’s look now at some more of the cool stuff.

Biostrap App – Insights

I suspect this is one of those areas where Biostrap will continue to add new functionality. Nevertheless, I like what I can already see as the RADAR Chart in the following image nicely shows how your individual bio-characteristics compare to ‘norm’ from Biostrap’s population of users – from the chart, I clearly have an HRV/nervous/over-training problem (my HRV was typically >80ms a couple of years ago).

Biostrap App – Meditation

This is a paid-for feature.

“Meditation” is one of the activities and you manually start to record after choosing a suitable duration.

You choose the length of meditation and then, whilst meditating, Biostrap plays some meditative music (from and Biostrap then produces a ‘Zen Score’ incorporating the metrics recorded which can include SpO2, HRV, and respiratory rate. A meditation session is then treated as a workout and is included in the activity timeline and, once processed, you can see details like this…

(not my data)

Biostrap App Review – for Activities

You can record many activity types and later there is a post-workout view of your activity which can include a GPS plot if you were linked to the app whilst you exercised with GPS enabled on your phone. Other information like cadence, distance, time and average speed/pace is also shown.

The app+wristband+footpod is very much simply a recording device, there is no visual/audio feedback during your workout of the type you would see on a sports watch.

Perversely, you don’t need the strap for recording a run. I just went for a run using only the footpod, smartphone app and external HRM (Polar OH1)

Sports like swimming are also covered and, again, the post-workout view of the data is fairly sparse.

Don’t expect the ACTIVITY VIEW to match Fitbit, Apple, Garmin, Suunto, Polar and the like. It doesn’t. I’d say that Biostrap rightly does not need to show such detailed data here.

Biostrap App Review – for Strength & Conditioning

Using Biostrap’s footpod and wristband, the app can be trained to recognise what exercise you are performing. I’ve never come across another app that does this by also using a footpod.

You choose the exercises you might ever use from a library (you can create custom ones) and then you perform 12 reps against each exercise so that the app recognises the motion patterns you produce as you perform the rep. The exercises can easily be re-trained in the future but this only needs to be a one-off task.

The advantage of this approach is that you don’t have to tell the app what exercise you are performing you just crack on with the full session and let the app do the recording. Rest periods are prompted by the app and so are the weights used (later versions of iOS can take voice input, earlier versions of iOS take a manual input).


Biostrap App Review – for Teams

Read this section if you want to keep track of a friend as well…

This is another neat potentially neat feature and is referred to in the app as REMOTE MONITORING. It’s mostly intended for a coach to request the access from those he trains but the feature could work equally well with you seeing your friend or partner’s stats.

I particularly liked the inclusion of this feature as it would typically be provided in other products as a paid-for ‘pro’ feature and be geared towards sports teams/coaches but the consumer sharing of the data side of things is kinda STRAVA-esque…but with physiology data.

Once an existing Biostrap user has accepted to let you see their data via a request in the REMOTE MONITORING section of the app, then you can return to the dashboard and switch to see the other user’s dashboard. It’s pretty much the same dashboard components and detail that you see for your own data – as far as I could make out.

Biostrap App – Alerts & Notifications

I still live in 2003 and like to be sent alerts by email. But most of you will like Biostrap’s alerts and notifications that are instigated by the app and shown on the app. Often some interesting feedback pops up, like this, which is fairly self-explanatory.

I also used my iPad at the same time and that seemed to regularly have lots of notifications from the Biostrap app informing me that so-and-so an activity had finished processing. I’d probably turn that off but I’m sure some of you will like to be kept up-to-speed with what the app is doing.

Biostrap Vs Whoop

When considering Biostrap vs. WHOOP the price is one of the most important factors on people’s minds. With WHOOP’s recent pricing change to a subscription-only service, Whoop is clearly positioning itself as a more expensive premium service provider.

WHOOP (left) and Biostrap (Right)

Biostrap EVO lets you go for the base product (paid for) but then optionally to add on premium features. I prefer this pricing as it gives the consumer more leeway to tailor the product experience to what they actually need/want but also it allows the customer to opt-in or out of the premium features. With WHOOP it’s all or nothing.

WHOOP’s default strap was not universally liked but I got and used the HYDRO strap which I thought was pretty cool. The clasp mechanism of WHOOP was quite secure but after my review, I did read reports of other users breaking it. Either way, I still prefer the slightly larger, flatter WHOOP form factor and better-secured clasp mechanism to that of Biostrap.

WHOOP is also better at giving a simple ‘readiness’ guideline as a single number, although Biostrap has since added this.

But that’s the point where I start to digress away from WHOOP and to prefer the features found in my Biostrap EVO review unit.

Biostrap’s data set is pretty cool. It gives enough areas of relatively unusual data insights to keep certain people engaged with the app and it does that without becoming too data-techy – a criticism that could be thrown at the sleep tool EMFIT, for example.

I love Biostrap’s wealth of insights and features around the basic train & sleep stuff….meditation, deep sleep analysis, physiology data sharing.

WHOOP (left) and Biostrap (Right)

For some athletes, Biostrap has a distinct advantage over WHOOP in that it can get the CORRECT input data for activities from an external strap. I have to stress again how the accuracy of that part of the readiness/recovery jigsaw puzzle is important to then go on to infer the correct levels of strain/activity and subsequently the ‘correct’ recovery/readiness.

To sum up Biostrap Vs. WHOOP, neither particularly stand out as being great trackers of your sporty endeavours in terms of comparing to the insights you would get from, say, Garmin or Polar but Biostrap does offer something a little more special in how it can be trained to recognise and record your S&C activities.

Biostrap Evo Review Alternatives

My Biostrap EVO review unit was good and compared well with some of the competition if you want to research wider, try these

Biostrap Evo Review – Futures

Here is what Biostrap could add to increase the awesomeness rating of their product further

Biostrap EVO Review – Bugs

Any bugs that I find in my Biostrap EVO review unit could be fixed tomorrow. I see that the nature of a product review is to assess the ‘experience’ of the product and to test some of the vendor’s claims. So, a review  ‘experience’ is more to point out design faults rather than report bugs.

Biostrap EVO Review – Summary & Recommendations

Overall, the Biostrap is a solid RECOMMENDATION.

I can and have made several relatively minor criticisms in the review but the bottom line is that Biostrap DOES WHAT IT SAYS ON THE TIN. It does NOT make any outlandish claims and it works well. The only exception to that would be the SLEEP STAGE info which all vendors ‘estimate’.

The key strengths of Biostrap are that it provides a well-priced, unique and comprehensive package of insights & functionality, namely:

Deep Sleep Analysis – Meditation – SpO2 – Leg/Arm Movements – HRV – Trained Exercise Recognition – Team/Family Sharing – The list goes on…

It would seem that there are three broad consumer types that will benefit most from Biostrap and these are:

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Biostrap EVO Review – Price, Discounts & Availability

Biostrap is available directly from the manufacturer or EU distributor and you will not find any new ones either on Amazon or in retail stores. If you use the link below plus the coupon code “the5krunner” then you get a 10% discount…thank you.

USA Manufacturer Link: 10% discount with code “the5krunner”

USA Manufacturer Link: 10% discount with code “the5krunner”

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