VO2 Max Explained: The Fitness Score That Predicts How Long You'll Live (And How to Raise It)
By Great Fitness and Health | October 2026 | Reading time: about 12 minutes A few years ago, a colleague of mine, a man in his early forties who walked his dog daily and described himself as "reasonably active," went for a routine fitness assessment at his gym. He expected a pat on the back. Instead, the trainer showed him a number: his estimated cardio fitness was in the bottom group for his age. He laughed it off at first. Then he asked a question many of us eventually ask: "Does that number actually matter?" It does. In fact, a growing body of research suggests that this one number, called VO2 max , may be one of the strongest predictors of how long and how well you will live. It is more informative than many of the things we obsess over, like the number on the bathroom scale. The good news is that VO2 max is not fixed. You can raise it at almost any age, and you do not need a laboratory, a marathon plan or an expensive gadget to do it. In this guide, w...