[header] How to measure vo2 max [title] Determine your resting heart rate. [step] Many fitness trackers and watches come with a heart rate monitor. If you have one of these, record your heart rate while at rest (sitting down, doing little-to-no physical activity). 
The best time to measure your resting heart rate is in the morning before you get out of bed. [substeps] To determine your heart rate without a monitor, place two fingers against the artery on the side of your neck, just under your jaw.