This test can be used for all populations, such as average adults, athletes and older adults. For average adults and athletes, this test is meant to estimate VO2max, or maximum oxygen uptake. This is the amount of oxygen in milliliters your body can use per kilogram of body weight per minute. Results of VO2 max are expressed as mL/kg/min. The Bruce protocol is a stress test for older population to assess their risk for cardiovascular disease or abnormalities. Older adults use an EKG with nodes placed on their chest so a professional clinician can monitor heart patterns.