Whoop 4 Review – Everything You Need To Know Before Buying The New Whoop Strap

If you are wondering “Is the Whoop Worth It?” or “What Does Whoop Track?”, this is where you get your money’s worth out of the Whoop 4.0. The Whoop 4.0 features some unrivalled data collection and display using some really cool and user friendly data sets like the Strain Coach, Sleep Coach and Recovery.

The Whoop also uses other great features like the Whoop Journal and Smart Alarms to increase the effectiveness and actionable functions of using the Whoop. With it’s intelligent features, the Whoop can tell you how hard to train, when to rest, when to go to sleep and wake up, give insight into habits, foods and supplements that are good or bad for you and essentially how to optimise your life.

Strain Coach

On of my favourite features of the Whoop 4.0 is the Strain Coach. The strain coach really takes the guess work out of how hard you can go in training and gives you a good idea of when you need to back off the training intensity and your ability to perform.

As I went through my 30 days of using the Whoop for this Whoop review, one of the features I wanted to get a good handle on was the Strain Coach. Despite the temptation to always just give 100% in a given workout or activity, the Strain Coach is an effective way to actually encourage you to listen to your body.

For example, I went through a super emotionally taxing time where my Whoop recorded a strain of 14.9 and a peak HR of 200, this was sitting in a car driving! Usually, I would have dismissed this as something that would not effect my stress or strain levels and am still primed to train. What the Strain Coach is great at, is removing this guess work and showing the true daily impact of every little moment over the course of the day whether it is activity strain, work stress, emotional stress, effects of food, drink and alcohol and other stressors that you might not think have an impact on you.

The Strain Coach can be turned on or off, and basically gives you a dial reading with a number indicating how much strain or effort you are primed to deliver in a given day, based on your recovery score.

With the Whoop 4.0 a haptic vibration alarm will give a couple of vibrations on the device when you have hit your recommended strain score for the day, one of the very few intrusive features of the Whoop.

Why is the strain coach useful? The Whoop Strain Coach, gives you a target for output based on your recovery from you previous days sleep score and all other recovery metrics like HR, HRV, Skin temperature and respiratory rate. By sticking to your Strain coach indicator, you can stay within reasonable requirements for sleep so as to not incur heavy sleep debt and continued poor recovery levels. 

Sleep Coach

Whoop steers you away from the one-size-fits all approach of simply assuming you need 8 hours of sleep. For many people, 8 hours is sufficient sleep for an effective recovery and to operate at their peak. Your sleep needs are largely dependant on your levels of exertion, stress, illness, injury and other factors, so 8 hours is not always on the money.

Whoop 4.0 is fantastic at giving you unique insights into your body and your own sleep needs based on how well you have been sleeping and how strenuous your day has been. The sleep coach is one of my favourite parts of having the Whoop and is a piece of data that really keeps me excited to use the Whoop.

Whoop establishes your baseline sleep after a couple of nights using the Whoop strap. Then, once you have a full 30 days of use, it compares your sleep statistics to your previous 30 days. With your baseline in mind, the Whoop takes your sleep debt, any naps you have taken and your recent activity or ‘strain’ and calculates your sleep needs.

This is a really good feature that we love as it takes away the guess work out of how much sleep you think you need and removes the standard way of thinking that 8 hours sleep is the golden number regardless of your individual daily outlook for stress and movement. With the sleep need, you can then set your alarm based on these sleep needs, to a specific sleep goal, or to an exact time.

The Sleep Coach gives you a suggested bed time and suggested wake time to achieve your sleep goals or if you need to wake up at an exact time it will estimate how much of your sleep need you will likely meet.

Whoop Sleep Metrics

The Whoop is one of the best sleep trackers we have tried, without a doubt. The Whoop uses a common 4 stages of sleep to portray data and breaks your sleep up into Awake, Light, Deep Sleep and REM Sleep.

The Whoop also gives an indication of your wake events, sleep efficiency (sleep latency), and respiratory rate for showing sleep quality. This is all fantastic information as it is very difficult to know how well you actually sleep without wearing a tracking device apart from an overall ‘feeling’. If you are experiencing a lot of wake events (my average is 1.5 per hour), low sleep efficiency and a high respiratory rate, it may indicate that you have poor sleep hygiene, poor nutrition and need to change up some habits around sleep like having an earlier mealtime before bed or reducing caffeine consumption later in the day.

While we are not sleep experts, we do know that periods of wakefulness are normal, light sleep makes up the majority of your sleep cycle, deep sleep is the body repair and healing phase and rem is the mentally restorative and learning phase.

I love all of the sleep data that Whoop shows, as it gives you a breakdown in minutes of how much time each phase contributed to your overall sleep ‘session’. Interestingly, I can attest to the accuracy of the Whoop for the sleep efficiency metric as it was able to pick up times when I was in bed but on my phone for a period before actually shutting off, indicating a lower sleep efficiency percentage.

Buy the Whoop 4.0 online at Whoop

Whoop Journal 

The Whoop Journal is a surprisingly important feature of the Whoop 4.0 and is really only useful if you actually engage with it. The Whoop Journal allows you to discover the effects of certain habits, practices, foods and behaviours on your recovery, mood and sleep.

The Whoop journal is something I would strongly recommend inputting as much of your data into daily in order to get the most out of your Whoop device. Essentially, you can add in elements to your journal that are a regular or irregular occurrence in your daily life like caffeine, alcohol, meditation, anxiety and other practices and behaviours to see how they interact with each other.

For example, while you may think that coffee has very little effect on you if you consume it late in the day, close to sleep or generally heavy consumption, when you limit your consumption and record it in the Whoop journal you may find that your sleep, and therefore your recovery, improves out of sight.

The Whoop Journal can also take the guess work out of what sort of food choices are having a negative impact on your health. You can get insight into the best diet suited to you like paleo, vegan, plant-based, keto or Mediterranean diet and how these food choices contribute to better or worse scores. You can even track how medications and supplements like Melatonin, Creatine, Fish Oil, Magnesium, L-theanine and other popular health supplements or prescribed medications affect your sleep.

There are over 100 behaviours you can track using the Whoop Journal and you can choose to engage with it daily if you are trying to get super specific about elements of health and wellness you want to explore or you can dismiss this function and focus on the other important data. 

Whoop Recovery

The Whoop Recovery data set is perhaps the most useful part of the Whoop for athletes and those who are very interested in their recovery levels and when they should train or when to back off the intensity.

The Whoop collates all of the important bits of data collected from your sleep including your sleep performance to give you a highly personalised snapshot of your ability or readiness to perform.

In a nutshell, your Recovery Score reflects how well prepared your body is to take on added Strain from exercise, work, competition, or other stressors and is an indication of how close to homeostasis (your natural resting state) your body is. Your Recovery level will also give you an indication of how much sleep is required to meet recovery needs into the next day.

By paying attention to your Recovery score, you can then base your workouts including the effort, intensity, load and volume that you add into your sessions. Adhering to your recovery score recommendations by way of your Strain coach, makes it easier to calculate how primed you are to take on a training regime or when you require rest to avoid injury, overtraining and burnout which is so common among athletes. 

The Whoop Recovery function combines resting heart rate, heart rate variability, respiratory rate, sleep performance, blood oximetry and skin temperature on a given day and shows this with a coloured dial and percentage, broken down into red, yellow or green. Because everyone operates on a different scale depending on your current baseline levels, Whoop establishes this baseline by creating 4 days of data before giving recommendations.

Recovery is reported on a 0-100% scale and divided into three stages: 

Green = Sufficient Recovery. 67% or above. Once you start to nail the sleep requirements and add in practices like breathwork, ice baths, sauna therapy, and good supplementations and hydration protocols you will find yourself in the green and feeling on point to push the body, being primed to adapt to a larger training load.

Yellow = Adequate Recovery. 34% – 66%. When I first started using the Whoop I was regularly sitting in the Yellow zone for recovery and this indicated to me that my current levels of perceived adequate sleep were off the mark. In the Yellow you are still able to adapt to high training load but might be compromised due to insufficient rest. This would indicate that you should limit super intense training. 

Red = Low Recovery. 33% or below. If I am in the red zone for recovery I generally take the day off training and adjust some habits like increasing hydration, increasing sleep and increasing meditation while reducing stress and partaking in active recovery practices like stretching, yoga walking to minimise strain. 

Whoop Health Monitor 

The Whoop 4.0 gives some other metrics laid out in a smaller bar on your daily summary page on the Whoop App. The five metrics in the Health Monitor sections include Respiratory Rate, Blood Oxygen, Resting Heart Rate, Heart Rate Variability and Skin Temperature.

All of these are super important metrics to know and are figures that really indicate how well recovered you are, what physical and mental state you are in and how well primed you are to perform.

Respiratory Rate

Your Respiratory rate is the amount of breaths you take per minute and is a general indicator of cardiovascular fitness. A normal range is between 12 and 20 breaths per minute for most people.

What the Whoop shows you when your breathing rate is out of whack is that your oxygen demands have changed and that you may require more rest or change in diet or daily habits. High respiratory rate or an increase from your baseline can indicate anything from an illness, anxiety and stress, poor environment like air quality, allergic reactions, dehydration and more. Decreases can indicate obstructive sleep apnoea, drug use, hyperthyroidism and more.

Engaging with the Whoop Journal, I found that when I increased by intake of gluten containing breads and pastas, my respiratory rate increased among other metrics.

Blood Oxygen

On the Whoop, your blood oxygen reading is given as a percentage like most devices. Blood oxygen is an important metric as it indicates how oxygenated your cells are and in turn how well your lungs, heart and circulatory system are working in synergy.

For most, the typical blood oxygen level is 95-100%. Anything below this would indicate a potentially serious issue and can show a pattern of poor chances of recovery if your 02 levels are low consistently.

Resting Heart Rate

Your resting heart rate is the number of times your heart beats per minute when you are at rest. The Resting Heart Rate (RHR) is a strong indicator of cardiovascular health and levels of recovery and stress.

Heart Rate Variability

Heart rate variability is literally the variance in time between the beats of your heart. The perception is that your heart beats on a regular interval in a given time period, but this is generally false. Your heart has slight variations in beats per minute that represent your heart rate variability. In short, the greater this variability, the more primed or ready your body is to perform and take on strain. If your HRV is low, it may indicate that you have had poor sleep, are in a state of stress, are consuming too much alcohol, have a poor diet and hydration, or are in a state of nervous system strain.

When I first started using the Whoop, my HRV was sitting at around 45. By following the strain coach and sleep coach to a reasonable proximity, I was able to increase my HRV by about 20 points within the space of a few weeks.

We have written about the importance of HRV in some of our other articles and use this recovery metric as one of the most important indicators of how well recovered we are. When HRV is low, add in extra sleep, more meditation, extra hydration and reduce alcohol consumption as an easy way to increase it. When HRV is high, know that you are primed to train hard, race, compete and give extra intensity in your workouts.

It is worth noting that generally, your HRV score will decrease on average as you age, and Whoop has an algorithm that factors these age and gender characteristics into the device. “The middle 50% of 20-25 year olds usually have an average HRV in the 55-105 range, while 60-65 year olds tend to be between 25-45.”

It is worth taking a look at the HRV graph displayed on the Whoop website to see where you should be aiming. As a 31 year old male, I am aiming for between about 50-80ms for my HRV.

Skin Temperature 

Skin temperature is an addition to the Whoop 4.0 that the Whoop 3.0 did not have.  

“Normal skin temperature for healthy adults ranges between 92.3 and 98.4 Fahrenheit or 33-37 Celsius, far lower than the 98.6 F average core temp. Changes in skin temperature may indicate potential illness or injuries.” 

Skin temperature is a big indicator of the state of the nervous system and the health of the body. Just think, when you have a fever or are sick you can express the poor state of the body with either a very hot skin temp or a very cold one, or even going from one to the other.  

You skin is your largest organ and shows a lot about your current state, which is why the Whoop tracks it and includes readings on the Health Monitor section of the data. The Whoop uses your previous 90 days of data to establish a good skin temperature baseline as every one is slightly different. What can you do with skin temperature data from Whoop? Well, if you continue to register a high skin temperature, for example, even during cold nights, it may indicate that you are using too much heating and would benefit from turning on a fan, reducing blankets or removing sleep clothing like socks or pants.

I have found that sleeping nude significantly regulated my skin temperature and contributed to a better sleep score overall, as an example of what you can try to manipulate skin temperature while you sleep. Another way I impacted skin temperature in a positive way was by taking a sauna or using a sauna blanket close to bed time which has a great rebounding effect on your core body temperature, effectively lowering core body temperature post sauna which is an effective way to fall asleep faster and stay asleep.

Whoop Battery and Charging

One of the notable and unique features I am attracted to by the Whoop is its charging mechanism and battery design. Unlike many devices that include the battery integrated inside the device, the Whoop features a slide on battery pack that is charged separately to the device.

In separating the battery from the device, the Whoop hardware has a small battery inside the device but reduces the size and weight of the device by excluding a charging port from the Whoop and making it magnetic clip-on, clip-off charging. This also means that Whoop users can purchase additional battery packs and have a ready supply of charged batteries to clip onto the Whoop.

Once fully charged, I managed to get about 3 full days of use out of the Whoop with daily activity use including tracking runs on GPS and 24/7 wear which I found quite impressive.

The battery pack can be worn while using every feature of the Whoop and I found it not too bulky to sleep with even with the battery pack clipped on. The battery pack takes about 120-180 minutes to fully charge using the micro USB connection and the battery pack charges the Whoop from dead flat to full battery within about 2 hours. 

The Whoop 4.0 Battery pack only offers one full charge for the whoop but features an auto-off or on function to conserve charging if needed. The battery pack can be worn in the shower and is water resistant up to one metre for 2 hours. Personally I would avoid charging in the water as the battery pack isn’t fully waterproof and would prefer to let the Whoop go flat for a period of time instead of risking water borne charging damage, despite being covered by the lifetime warranty.

Whoop Warranty

I truly can get around products that include a lifetime warranty – Whoop is one of these brands. As the Whoop is designed to be worn 24/7, it has to be able to take a fair beating. The epic thing about Whoop is that they cover any issues and problems with the device, for life, so long as you have purchased your Whoop directly and still maintain an active membership with Whoop. 

To facilitate this, and to reduce waste, Whoop also refurbishes their hardware. What this means is that when you purchase a Whoop you may be buying a refurbished device. Don’t worry though, all refurbishments are certified and covered by the Whoop lifetime warranty and undergo testing and inspection within a quality inspection process, and includes a brand new band, buckle and clasp. 

The lifetime warranty for Whoop places it in a cut above many other Whoop alternatives like the Biostrap, Oura Ring, Fitbit, Garmin, SleepOn Ring and other sleep and fitness tracking devices. Yes, the Whoop membership style pricing that entails a continued payment for the use of the Whoop means you will have to pay more for the Whoop in the long run compared to other ‘pay once’ devices, but this membership covers your lifetime warranty also.

Whoop Body – Whoop Clothing Line 

Not everyone likes wearing the Whoop on the wrist. For people who don’t like wrist worn fitness and sleep tracking devices, the Whoop also has a range of clothing that allows you to use the Whoop without having it visible or on the wrist which can be uncomfortable for some users.  

The Whoop Body range or smart apparel compatible with the WHOOP 4.0, includes boxers, bralettes, leggings, performance tops, and more. The Whoop Body range gives you the ability to simply remove the hardware from the Whoop strap and insert it into the specially designed pouch on the garment. This means girls can insert the Whoop into a sports bra top or guys can slide the Whoop into the training shorts and get the same tracking capability via a different area of the body.

Who Is The Whoop 4.0 Good For?