One thing I learned really late into the game is that if you want to have results in the gym, the time outside the gym is just as important. Apart from nutrition which I mentioned in a previous post, recovery and workout planning is a key factor in order to achieve results.

When I stumbled over Whoop, the initial promise of strain and recovery monitoring immediately resonated with me. Here are my thoughts three months into training with Whoop.

Disclaimer: Whoop does not ship to Europe, so I had my unit delivered to a hotel where a friend of mine stayed. Other than that I had no issues with the functionality of the device outside of the USA.

Update: Whoop announced today (10/09/2018) it will start shipping internationally to the following countries: Belgium, Finland, Denmark, France, Germany, Ireland, Italy, Netherlands, Spain, UK.

What is Whoop

Whoop has a hardware and software component. A strap with advanced tracking capabilities and a software platform analyzing the data, providing you with insights on your strain, sleep, and recovery. Since early 2018 Whoop is a membership service which means you pay $30 per month with a minimum of 6 months, hardware included. After 6 months you pay monthly for access to the software platform. I think this “pay as you go” setup makes a lot of sense and shows a great deal of confidence from the company in their product.

The Whoop tracker

The tracker consists of two pieces. The actual hardware doing the HR readings and the strap.

Whoop strap

The default strap that comes within the box (Tecnica) is a black nylon strap with an interior lining of red silicon dots for added grip. A clasp mechanism secures the tracker on your wrist. The HR reader measures HR with HRV, temperature, and motion. These do sum up roughly to 100 metrics per second. These metrics are transferred via Bluetooth to the smartphone application. The strap itself does not do any data processing. All raw data is transferred to the application and from there to the Whoop servers in order to do the data processing. Since this is the raw HR data the data transfer itself takes quite some time and is quite data intensive.


Heart rate variability is a hot topic lately with the fitness community trying to get a hold on as many metrics as possible in order to quantify all aspects of training. Research seems to link HRV and the Autonomic Nervous System.

This means that by monitoring your HRV you can understand how your body handles stress and adjust training and recovery to aid your body in the process.

Unfortunately not all trackers or fitness watches are capable of reading or submitting HRV. Latest generation Smartwatches from Garmin and Co equipped with the latest generation of HR readers can read HRV and integrate the metric into something they usually call stress score or similar. But since this is quite sensor and therefore battery intensive they usually rely on small bursts of tracking.

HR readings on the wrist

The Whoop band is advertised as a wristband. During my first days of testing, I was seeing high strain values even on my resting days. Unfortunately, as it turns out the wrist is a poor location for taking HR metrics. Below you will see the HR tracking during a normal - no workout - day. The first picture shows my HR with the band worn of the wrist, while the picture below shows my metrics with the band on my biceps (upon a suggestion from @raspberryjuice).

HR reading on the wrist

HR reading on the biceps

While it took me some time to get used to it, the readings are much more accurate and stable, plus it turns out the biceps is a very convenient location to wear the strap. Even during basketball games, I can simply wrap the band in a sweatband. With any other HR tracker, being it a watch or a chest band you would risk either injuring someone else or yourself.

The one problem I ran into was that you cannot alter data transmitted to Whoop. Since the tracker is building up a 30-day profile of your metrics, the first days of wrong metrics skewed the overall values by a lot, so I had to wait for some days in order for the initial metrics to drop out of the 30-day window. I also had some anomalies on some other days when the tracker wasn’t properly placed while I played/fought with the boys. It would be nice if you could just annotate the time period and tell Whoop not to take this period into account.

One downside of wearing the band on the biceps occurs while swimming. The resistance of the water combined with the swinging arm motions twists the tracker of the biceps. So for swimming, the wrist location is as good as it gets for me.


As mentioned the tracker comes with the Tecnica band. Durability might be an issue since it shows some signs of wear 3 months in. You can buy other band options, plus a biceps band which is practically a longer Tecnica band from the Whoop website. Unfortunately, they seem to always have really low stock. The Tecnica bands are very often sold out. Durability for the Tecnica band might be an issue, especially after a long summer visiting the Greek islands.

Display and connectivity

Whoop is a fitness tracker. This means it is not a smartwatch or a platform. It is more of a sensor array which makes absolute sense to me. Do one thing and do one thing well. You place the tracker on your biceps and forget about it.

There is no display, no vibration alarm no notifications which I totally dig. An Apple Watch does these things better anyway.

You can double tap the strap in order to light up three small but very bright led lights on the side of the tracker. Each light represents a certain amount of leftover battery life. With the tracker always sampling your HR at the same frequency the battery life is quite linear for some added peace of mind. Other fitness watches up the power requirements during a workout (sampling, GPS etc) thus making it hard to predict if you are good to go or you need to charge up.

The double tapping gesture also lets the Bluetooth radio reconnect to your phone if your connection is lost. Overall connectivity to the phone was very good, with some very minor issues which could be easily resolved by double tapping the tracker or restarting the app.

Battery and charging

What I absolutely love is the charging mechanism. With your Whoop tracker, you get a tiny battery pack.

Strap and battery pack

The pack should roughly have enough charge to charge your strap 1.5 times. The pack itself can be charged via MicroUSB which is very convenient since I can have it constantly connected to my power bank and throw both into my backpack.

When you want to charge your strap you simply slide the small battery pack over the tracker.

Three led’s on the battery pack light up to show you that you have it correctly placed and the current status of the band’s battery.

While I was initially a bit skeptical about this external battery pack approach I have to say that this has turned out to be one of my most beloved features. The band continues to work with the pack on it. So you have no service interruption like you do when you have to remove your watch in order to charge it. The band and pack aren’t that bulky so I often charge the band during bedtime. Finally, the pack is small enough to carry it with you everywhere, so the effective (fully charged tracker + pack) battery life is roughly 5 days which is more than enough.

Using the tracker and the Application/Website

The Whoop tracker is constantly tracking the metrics. 24/7, full throttle. While this might go unnoticed as marketing talk it has some really interesting implication when you actually use the tracker.

With the default smartwatch or fitness tracker, you have to manually start a workout which will put the HR sensor usually in overdrive mode raising the sampling rate. If you forget to start the workout you are usually left either with incomplete data, while many platforms do not allow to add a workout later on. The Whoop tracker never leaves overdrive mode, so even if you do not start a workout you never lose any data.

Right now and since I hardly notice wearing the tracker I just walk into the gym and start my workout. If the tracker recognizes your HR as elevated it will start labeling the data as a workout. If the workout is low intensity (weightlifting hardly gets me into high HR) you can easily add the activity and label it via the application. If you don’t label the activity your metrics are still affected the same way, since HR is elevated and the strain score shows up correctly. So labeling is actually optional and more of an organizational feature.


Strain is a metric for the cardiovascular activity of your body on a scale from 0 to 21. It is based on your max HR and your all-day heart rate. All out workouts are 18 and above; strenuous workouts are typically 14-18; moderate workouts are typically 10-14; and everything below 10 represents degrees of light or minimal activity.

Day strain is the overall strain you are seeing by not only taking workouts into account, but also that stressful evening commute, or maybe that afternoon you tried to teach your kid to bike :)

My off days hover around a 6, while a solid one-hour basketball training will add a 12-14 strain to my overall day strain. Since strain is based on HR metrics one-hour doing weight training will not add another 12 to my overall strain. Instead, I get a 5.

Basketball and weightlifting workout

This is one area where HR metrics are a bit restrictive. Weightlifting does not raise your heart rate but is just as tiring or should I say straining as cardio. So does this mean Whoop is no good fit for non-cardio activities? Well not exactly, let’s look into recovery.


Your recovery score is calculated every morning after you wake up. It takes roughly 10 mins to get your recovery score. Recovery is based on resting heart rate, heart rate variability and length and quality of your sleep.

Daily recovery and weekly trends

Since all activities even low heart rate activities like weightlifting affect your body, recovery is a more complete metric of your last day.

Over the last 3 months I have found a strong correlation between my recovery score and how I generally feel after waking up. Even the occasionally troubled mind which will keep you awake at night is mirrored correctly by my recovery score. HRV seems to be the strongest factor since low HRV values, compared to your 30-day average, usually wreck your recovery.

The fact that recovery is available in the morning is logical but not very useful. I usually schedule my workout with my coach the day before training, so when I wake up with a low recovery I can’t simply avoid any strain. What I do is communicate my perceived and calculated recovery and hope @john_sour does adjust the workload :)

Sleep Coach

The third section of the mobile Whoop app is the sleep screen.

Sleep analysis

This section was my first revelation with Whoop. While I did use my Garmin Fenix 3HR in the past to monitor my sleep patterns, Whoop showed me the huge amount of sleep you loose, lying in bed but not really sleeping.

On average I am losing roughly 45mins from my time in bed, which means if I am gunning for a 7-hour sleep I should be almost 8 hours lying in bed!

I do not have any sleep conditions so I couldn’t gain any more insights from the sleep screen. Tracking of sleep happens automatically and the metrics are very accurate.

Keep in mind that the led lights on the tracker although very small are very very bright. I use them as a ambient light when waking up in the dark!

Weekly Performance Assessment

Some weeks ago Whoop added the Weekly Performance Assessment to the application. Every Monday morning you get a breakdown of the last week and a benchmark of one metric compared to a matching population segment.

The three section covered are:

  • Training Status: A diagram with your Strain distribution in order to gauge over/optimal/under-training
  • Sleep Consistency: For a birds-eye view of sleep patterns. The overall premise is that consistent sleep patterns help recovery.
  • Benchmark Comparison: For this week the benchmark was for calories burned.

Weekly P.A. Weekly P.A.


So what are my final thoughts on the Whoop tracker? At 30$ per month it isn’t the cheapest option, and after the first year the cost is nearing the cost of a very advanced smartwatch.

But this is where I think Whoop is different: Smartwatches are a mixture of possibilities and abilities but on the fitness tracking front I always found them lacking. Either the HR sensor or the battery life was subpar, or the software platforms associated with them had an all-around approach which made them average for everything.

Whoop is a very serious fitness device. You can wear it everywhere across a wide variety of workouts. Battery life linearity is very important, while the metrics and automatic workout recognition help me keep an eye on how I am doing. I will keep Whoop for tracking my personal wellbeing and fitness, while I will at some point switch to a smartwatch merely for notifications and time/alarm functionality.

By compromising on some things Whoop is able to excel at specific things, and this has always for me been a recipe for success.