There are a lot of things you should track as you age as a runner: your mileage, your heart rate, and your sleep quality to name a few. But are you paying attention to your VO₂ max?

Scientifically speaking, VO₂ max is the maximum amount of oxygen your body can take in and use, and it’s a marker of your cardiovascular fitness level.

🏃🏻‍♀️For everything you need to know about this trendy and telling metric, check out The Runner’s World Guide to VO2 Max .

For a variety of reasons, however, VO₂ max naturally decreases as you get older.

We recently took a deeper look at why this happens and why a regular running schedule is a great way for you to offset this decline. One thing you’ll find fascinating is the range of poor to excellent VO₂ max for men and women from their late 20s to their late 60s.…