VO2 max. is the maximum volume of oxygen (in milliliters) you can consume per minute per kilogram of body weight at your maximum performance. In simple terms, VO2 max. is an indication of cardiovascular strength and should increase as your level of fitness improves. The D2™ Air X10 watch requires wrist-based heart rate or a compatible chest heart rate monitor to display your VO2 max. estimate.

On the watch, your VO2 max. estimate appears as a number and description. On your Garmin Connect™ account, you can view additional details about your VO2 max. estimate.

VO2 max. data is provided by Firstbeat Analytics™. VO2 max. analysis is provided with permission from The Cooper Institute^®. For more information, see the appendix (VO2 Max. Standard Ratings), and go to www.CooperInstitute.org.