For a real-time assessment of your current ability to perform, look at your performance condition. During the first 6 to 20 minutes of your run, this metric analyzes pace, heart rate and heart rate variability. The resulting number is a real-time assessment of the deviation from your baseline VO2 max, with each point on the scale representing about 1% of your VO2 max. The higher the number, the higher you can expect to perform. Keep in mind that your results may vary a bit during your first few runs with a new device, since it’s still learning your fitness level. This will stabilize, and then checking your performance condition will become a reliable day-to-day indicator of your capability.