Hour Record‎ > ‎

Physiological Testing


The first step of our partnership with GU was to get some physiological testing done.  We went to U.C. Davis Sports Medicine Center  in Sacramento where we were given an electrocardiogram, a DEXA/DXA scan and performed a stationary bicycle test to find our metabolic efficiency and lactate threshold.

From the EKG we learned that my heart was in fact, still beating, I have a low pulse and that I probably wouldn’t die during the bike test.  Basically I figure that they are rightly covering their bases before the stressful bike test.

 Body Scanning

The DEXA scan was more interesting.   I learned that I have slightly low bone density.  Not bad, but not optimal.  Ironically I fared better than Dan who is younger and regularly lifts weights.  Though it’s entirely possible that much of my bone mass is in my skull as many others have inferred…  The scan also told me how much lean vs. fat mass I had in each limb, my torso and my head.  My right arm and left leg are leaner than their counterparts.  I learned that is pretty standard for somebody who is right handed.  But the important thing we learned (besides the bone density) is how many calories I need per day.

My Resting Metabolic Rate is 1,909 kcal per day

My Daily Caloric Needs (based on light activity) is 2,290 kcal per day.

Oh, and I need to lose a few pounds.  This I knew already.

Cycling Lactate and Energy Utilization

 For the bike test they put our time trial bikes on a computrainer in ergometer mode.  We were fitted with masks so that they could analyze our exhaled gases.  The mask was somewhat uncomfortable in that exhaling was harder work than without.  I had to concentrate just a bit to make sure I exhaled hard enough to empty my lungs for the next breath.  They started me at 130 watts and increased the power by 35 watts every 4 minutes.  Leading up to the end of the 4 minute period I was asked my Perceived Exertion on a scale of 1 to 10, then they’d bump up the power and squeeze a little blood out of my ear lobe to test the lactate level.  They called it after 4 minutes at 347 watts.  I was ready to do one more 35 step, but that wasn’t necessary for the purposes of that test.  I felt strangely disappointed.  Like I got cheated. 

The big take away from that test is that I am a sugar burner.  Big time.  One of the data points you get from this test is your “Crossover Point” where you are burning 50% carbs and 50% fat.  I did not have one.  Even at 130 watts I was burning more carbohydrates than fat. 

I wonder if this explains why I have to work fairly hard to stay lean as my tendency is to burn glycogen and not my fat stores.

My ventilatory and lactate (4 mMol) thresholds matched up fairly well at 310 and 318 watts.  Those are both really low compared to reality though, or at least what I consider “threshold”.  I use the power that I can sustain for 1 hour as my threshold power (or Functional Threshold Power, FTP).  Based on those numbers my threshold training zone would be 300-320 watts.  In reality though I can generally do 350-380 watts for an hour depending on fitness.  My takeaway is that I can reasonably sustain more than 4 mMol of lactate.

 Next step?  Blood testing and nutrition advice.