Before you begin the VO2 Max test, you place a mask over your nose and mouth and strap on a heart rate monitor. "It’s going to start reading your heart rate,” explains Dr. Darren Mitchell who runs the VO2 Max tests at South Reno Athletic Club’s Metabolic Center. Once the machine is calibrated, you begin the test by walking on a treadmill at a very slow pace. "It seems pretty easy at this point, doesn't it?” Dr. Mitchell asks. “Yeah, I'm enjoying it while it lasts.” As you walk, the machine monitors your inflow and outflow which will eventually determine how well your body uses oxygen during exercise.

"Now we're going to speed this up a bit." Once I started running at a comfortable pace, Dr. Mitchell changed the incline to raise my intensity, all the while watching my oxygen and carbon dioxide levels. "By how much those levels change - it determines what you're actually burning." Between fat, carbohydrates and, in some cases, muscle; what we want to avoid burning for fuel. Along with rating your cardiovascular fitness, Dr. Mitchell explains the VO2 Max test also determines your body's aerobic and anaerobic thresholds. While exercising, if you keep your heart rate below your aerobic threshold, experts say you burn more fat than you would training at a higher heart rate. This means consistently working out harder isn't always better. "That's the misconception a lot of people have – if I push myself really, really hard, I'm going to burn a lot of fat. You're not."

After about 10 minutes running uphill, Dr. Mitchell can tell I’m almost out of gas. On the monitor, he watches for the point that my oxygen and carbon dioxide level lines meet; it means my body is now consuming less oxygen than I need to keep going at this pace. "I'm sure you're hitting the wall about now." He was right!

Seconds later the test is over and the results are in. "Anything over 40 is superior,” explains Dr. Mitchell, “And you were a 45.8. So you did a great job!” I also have training numbers to help me workout in my fat-burning zone as opposed to my anaerobic heart rate zone.

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