Standards is a series explaining various tech protocols, looking at their practical implementation, and where we could find them in devices around us.

Fitness bands and watches have thrown around numbers at our faces and motivate us to be more healthy.

All these smart wearables have two primary measures: the number of steps taken and the number of active calories burnt in a day.

Apple pioneered the system to display three rings for calories, steps, and standing. It edges you to complete them out for the day to feel we’ve been active enough. Other smart band makers have also followed rings or a similar system for daily fitness goals.

Apple Watch design Series 1Apple Watch design Series 1

However, another fitness stat is gaining prominence in these wearable devices: VO2Max. It’s a metric that allows devices to calculate the intensity of your workout and cardiovascular strength.

What is VO2Max?

VO2Max stands for the maximum volume of O2 (oxygen) you can utilize during a workout. The measure’s unit is ml/kg/min, indicating that it takes into account the amount of oxygen in ml you can utilize per kg of body weight every minute. The score helps you improve your performance in activities that require better cardio fitness.

What’s it used for?

VO2Max is a measure of your cardiovascular fitness or endurance in simple words. It can give you a sense of how well you utilize oxygen while doing physically strenuous activity. The higher your VO2Max score, the more likely you can perform while playing sports, running, or cycling.

Unlike step counts and calories, VO2Max is not a universal score. It depends on your age, the work you’re putting in, and your activity over time.

Credit: Garmin/Cooper Institute
Vo2Max scores for males of different ages
Credit: Garmin/Cooper Institute
Vo2Max scores for females of different ages

How is it measured?

Typically VO2Max is measured for athletes in a specialized training facility where researchers and coaches measured their performance by placing various sensors on their bodies. One of the most important sensors is in a mask that measures gases that are being exhaled and using it to calculate oxygen consumption.

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Now, smartwatches don’t that many sensors attached to your body. So they have to rely on data from heart rate sensors. While some watches use photoplethysmography (PPG) — using flashing LEDs to measure blood flow and calculate heart rate — other modern smartwatches like the Apple Watch use ECG (Electrocardiograms) and PPG both for more accurate measurements.

Firstbeat analytics, a company which is now owned by smartwatch maker Garmin, is one of the leading companies to develop an algorithm to use data from heartrate sensors, accelerometers, and gyroscopes to measure VO2Max on wearable devices.

The company said that it also takes into account other factors such as the speed of your movement and, the inclination of your running, walking, or cycling activity to gauge how much work you’re putting in.

The firm claims that its algorithm is 95% accurate compared to the lab tests. You can learn more about how aerobic fitness related to VO2Max and how Firstbeat analytics converts it into a measurable algorithm in this white paper.

Where you could find it?

VO2Max is a common measure in many mainstream fitness trackers. The world’s most popular smartwatch, the Apple Watch, also lets you measure your cardio fitness. The score is not one of the main measures featured in three circles that are core toApple’s fitness ecosystem. But you can find the VO2Max score under Cardio Fitness in the Apple Health app.

Apple Watch VO2Max
Credit: Apple
Apple Watch VO2Max
Apple Watch VO2Max

Since acquiring Firstbeat analytics, Garmin has also made VO2Max an integral part of its fitness measurement system. Plus, it’s going to take into account other factors such as altitude and temperature to give you a more accurate score.

However, the measure is not just limited to high-end smart wearable devices. It’s also found in budget fitness watches such as the $136 Mi Watch revolve.

How to improve your VO2Max score?

Improving the VO2Max score requires continuous and regular activity. So, you can’t expect to work out a few days and slack off a few weeks to get an improved score.

Ideally, you want to do workouts that have a higher intensity of cardio activity to improve your VO2Max score while dedicating days for recovery. The idea is to maintain the intensity of the workout for a longer period of time.

The company is now also suggesting various workouts in its app to improve the score.

Rahul Shingrani, the founder of India-based startup Ten3T healthcare, said that VO2Max has typically been used to measure the fitness level of athletes and train them accordingly. But more people are finding new ways to focus on long term fitness after witnessing the pandemic:

VO2Max measured has shown up in mainstream smartwatches and fitness trackers such as the Apple Watch in last few years. Given people are more health-conscious after looking at the COVID-19 pandemic, VO2Max is one of the stats they could look at to improve their overall fitness.

Time to get your butt off the sofa.

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