Running Index is an estimation of your maximal oxygen uptake (VO2max) in running – a score that helps you see how efficient your running training is and how you can improve your maximal aerobic running performance.
Running Index helps you understand how efficient your running training really is. When you follow it over time you’ll see how your running performance develops.
You get a Running Index score after every run. It gives you an estimate of your maximal aerobic running performance.
Follow your Running Index report in Polar Flow. When your aerobic capacity and running economy improve your running index goes up.
Running Index is a good predictor of race performance in endurance running. Your Running Index report in Polar Flow will show you an estimation of your finish time on different running distances.
You can also use Running Index to compare your aerobic fitness level to people of the same age and gender.
Running Index is based on the linear relationship between heart rate and oxygen uptake – when you run faster, your muscles need more oxygen to produce energy, so your your heart needs to pump blood faster and your heart rate goes up.
Your Running Index score is calculated automatically after every run. We use your heart rate and pace during your run and your resting heart rate and maximal heart rate values to estimate your maximal aerobic running speed on a level ground. This speed estimate is then converted to an estimate of running VO2max, in other words your Running Index score.