You will do this test on an exercise bike with sensors wired to your chest. (NOTE: for men whose chests are hairy, we may need to remove a small amount of chest hair to properly attach the sensors). You will also wear a mouth mask that contains sensors for the breathing gas analysis as well as a cuff around your upper arm to monitor your blood pressure. The test starts with you pedaling the bike at a low resistance. Gradually the resistance increases. The intention is that you make the maximum physical effort for as long as possible. You and your heart registration will be constantly monitored. Once you reach your maximum, the test will end and you can stop pedaling. We will continue to measure your heart rate for a few more minutes to track your recovery. The total test time including instruction takes approximately 20 minutes.