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 athletic performance and should increase as your level of fitness improves. The fēnix^® Chronos device requires wrist-based heart rate or a compatible chest heart rate monitor to display your VO2 max. estimate. The device has separate VO2 max. estimates for running and cycling. You must run either outside with GPS or ride with a compatible power meter at a moderate level of intensity for several minutes to get an accurate VO2 max. estimate.

Your VO2 max. estimate appears as a number and position on the color gauge.

VO2 max. data and 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.