Hi, Team. Some great questions around VO2 max have surfaced from the community via Twitter, Facebook, and other channels. I’m going to add some insight and context around VO2 max, and how Microsoft Band and Microsoft Health work together to estimate it.
Anyone who’s ever had their VO2 max tested in a traditional lab setting can tell you that it’s not the most pleasurable experience. Not only is it expensive, it requires a technician, some fancy equipment, and a mask over your nose and mouth to capture your air exchange while running at your maximum effort. You can get an idea of the experience, and more information about it, by watching my colleague Clark go through the paces in this video.
Though the most accurate way to determine your VO2 max will always be in a lab setting, your Microsoft Band can estimate this value using your biometric data, speed, and heart rate each time you go for a run, whether it’s outside or in the gym.
But before we dive into exactly how that works, let’s cover exactly what VO2 max represents.
VO2 Max. What Is It?
Your VO2 max represents the maximum amount of oxygen (O2) you can consume and utilize during exercise at maximum effort, and is widely accepted as the gold standard for classifying your cardiovascular fitness level. If your band has estimated your VO2 max, you’ll see the value in your About Me page in the Microsoft Health web dashboard (you can see an example of my colleague Lindsey’s VO2 max in the image at the top of the page). If your VO2 max is displayed, the numeric value you see represents the estimated maximum amount of oxygen you can consume (in milliliters) for your bodyweight (in kilograms), during one minute of exercise (ml/kg/min).
Because this isn’t a commonly understood unit of measure, it’s much simpler to just remember: the higher your VO2 max, the higher your cardiovascular fitness.
How Does Microsoft Band Estimate My VO2 Max?
To estimate your VO2 max without measuring the actual exchange of air inhaled and exhaled during exercise, the key inputs necessary include your biometric information (height, weight, age, gender), running speed, and heart rate, which are evaluated when you use the Run Tile. Your band uses its built-in GPS to capture speed if it has been activated while running outdoors. If GPS is turned off, or if you’re running indoors, speed is evaluated using the accelerometer, measuring your stride length and rate, specific to your height. Your band’s continuous optical heart rate monitor keeps track of your heart rate.
There is a direct relationship between speed, heart rate, and oxygen consumption during your runs. As your speed increases, so too does your heart rate, and your rate of breathing increases to provide needed oxygen to your working muscles. A database of thousands of VO2 max performances with matching biometric data is then used to estimate your oxygen consumption.
I’m Flattered by My VO2 Max Estimate, But That Can’t Be Right. Can It?
The VO2 max displayed in your dashboard is only an estimation, but you’d be surprised by its accuracy. That said, there are some common scenarios that may result in an over- or under-estimation of your VO2 max.
Because the relationship between your running speed and heart rate are the key measures used to estimate your VO2 max, running uphill or downhill can alter your estimation for better or worse. When running uphill, your heart rate is typically higher and your speed is slower, indicating a lower fitness level that can result in an under-estimation of your VO2 max. On the flip side, running downhill is easier, meaning your heart rate is lower while you’re running at a faster speed, resulting in an over-estimation of your VO2 max.
How Can I Get the Most Accurate VO2 Max Estimate?
For the most accurate estimation of your VO2 max, here are a few tips:
- Try to find a consistently flat surface so the relationship between your speed and heart are truly indicative of your fitness level.
- Avoid stop-and-go running, as much as you can. A more continuous run will result in more reliable heart rate and speed data, which is used to estimate your VO2 max.
- You don’t have to run at max speed, but a strong effort (relative to your ability) can result in greater accuracy of your estimate.
- Microsoft Health requires a minimum of five runs before estimating your VO2 max. This allows for ample reliable data to be captured before calculating your estimate. If your estimated VO2 max does not appear in your web dashboard after five runs, more reliable data may be needed. Keep tracking those runs, following tips 1-3. You’ll get there!