Cycle Physical Fitness Evaluation: Aerobic Capacity 2 times
First up is the usual needle stick to insert a catheter for blood draws, and then the scientists put electrodes all over my chest and abdomen, hooking up lines to their various equipment.  I laid down on a padded table for a 5-minute quiet period, so they could get a recumbent BP, tape a sensor to my forehead and affix a NIRS (near infrared spectroscopy) pad to my left thigh.

During exertion, the NIRS sensors deliver cool light to the skin, which penetrates muscles and is then reflected back to the sensor to analyze the amount of oxygen in the bloodstream.
They carefully fitted a headband attached to a snorkel-like mouthpiece on my head, then nose clips.  I was practically bionic at that point!  While cycling, I breathe only out of my mouth into a flexible hose and exhalations are measured in volume as well as analyzed to determine caloric consumption, or your “metabolic rate.”
The Drill: You start cycling until you work up to 75 RPM at no resistance.  No problem.  After 3 minutes, they up the resistance a few notches… not enough to feel it in the muscles, but a little harrier than the bike-resistance levels on a Precor in the average gym.  After another 3 minutes, resistance goes up again, and then you start to feel it in the calves and quads… they warn you when it’s time that you’ll feel an increase, so that you can maintain the 75 RPMs.  And so it continues, until you cannot go any further. 
While being strung up like a marionette and trying to maintain this activity level, Michael took a blood draw around the 8-minute mark, Rosario conducted live echocardiography, every few minutes Mark told me to relax my left arm so he could take a blood pressure reading, and Kurt would grab my finger and do a quick pinprick to get a sample for measuring blood lactate.  Chaos!
The resistance kicked up again, at which point it starts to be a strain to have all this going on around your body AND trying to breathe AND trying to keep your burning legs pumping.  When the lungs begin to burn and it’s difficult to continue, you slow into a cool-down phase where they continue collecting expired ventilation, and collect one last blood draw.  BP monitoring also continues, and after 5 minutes you get off the bike, have some water, etc.
There is always a doctor there who is trained in “Advanced Cardiac Life Support,” just in case anything goes wrong.  They ask questions about symptoms, any pain, etc. as they continue to monitor breathing.  They examine the summaries to see peak heart rate, peak blood pressure, etc.  Then you feel like death for a few minutes... but about a half hour later you feel great!