Altitude Training and Testing

I’ve frequently done a period of altitude training at Mammoth Lakes before competitions at altitude such as before the Sattley time trial championship, master track nationals at Colorado Springs or road master nationals at Bend OR. This year I decided to be more systematic about trying to identify the benefits, or lack thereof, of the altitude training. Also I’ve previously done three weeks or less of altitude training but bumped that to a full month this time based on reports in the technical literature that there’s a worthwhile gain in performance in going from three weeks at altitude to four weeks. This document is a detailed report of what I did.

My basic plan was to monitor as many parameters as I could before, during and after the altitude training. The following tests were included in my plan.

  • VO2max testing
  • Sea level before altitude
  • Immediately after arrival at altitude
  • Shortly before leaving altitude
  • Sea level after altitude
  • Max effort 3-minute test on time trial bike
  • Sea level before altitude
  • Weekly tests at altitude (4)
  • Sea level after altitude
  • Blood test
  • CBC blood test before altitude
  • CBC blood test immediately after return to sea level
  • Monitor basic parameters daily
  • Weight
  • Blood pressure
  • Morning resting heart rate
  • Oxygen saturation

There are two types of performance testing – laboratory based and field tests. Both types are useful and I wanted to include both for my study though both my coach Dan Smith and I consider the field tests more meaningful since they are more representative of what you can do on your bike on the road.

The table below shows the course of activity during this training and testing period. It’s color coded to show elevation levels for the various activities. The date cells are coded for sleeping altitude.

The workouts at Bishop were actually done about twelve miles north of Bishop at an area known as Round Valley at elevation 4550 feet. The reason for doing workouts there is based on the training principle of “sleep high, train low”. Coach Dan has me do all my more intense interval work at a lower elevation where it’s possible to work at a higher intensity than at the higher Mammoth altitude. Also it’s good preparation for my competition at the Sattley Time Trial Championship which is at 4900 feet elevation with only 350 feet elevation difference. The roads at Round Valley are mostly flat, of good surface and with light traffic. For those familiar with the Everest Challenge stage race, these roads are part of Day 1 of the EC race.

Days where there is no indicated workout were endurance and climbing rides done near Mammoth at altitudes between 6800-7600 feet.

There were 30 nights spent at 8000-foot altitude at Mammoth and 2 nights at 6000-foot altitude in Truckee prior to the time trial championship at Sattley.

The photo is of me and AV teammates Ivan Tarasov and Alexandra Yakovleva riding in the Round Valley area. Alexandra will be competing in the June Lakes Triathlon in July. She and Ivan stayed with us for a few days at our rented condo which gave her a chance to reconnoiter the bike and run courses of the triathlon. The mountain in the background is Mt. Tom, just part of what makes this area such a beautiful place to ride.


VO2max Testing

If you’re not familiar with how a VO2max test is done in the lab you’re in luck to have avoided the experience. They can be quite unpleasant, to put it mildly. The tests are done on a treadmill for runners or on a stationary bike. In my case both of the sea level tests were done at Stanford University using my own CompuTrainer and road bike that I took with me to the test. After a warmup period on the bike a large mouthpiece is inserted which is connected by plastic tubes that go into a metabolic cart where your oxygen and carbon dioxide are measured. Your nose is clamped shut with a pinch clamp so all breathing is done through your mouth. Here’s a generic picture of a cyclist being tested.

The test begins at a moderate power setting and then the resistance of the trainer is ramped up in fixed steps at regular intervals. For my sea level tests the resistance was increased by 30 watts every three minutes. You “simply” keep pedaling the bike to failure (you can’t pedal any longer and have to stop). Cadence is self selected but expected to be maintained fairly constant during the test. My cadence was 91 RPM.

The tests at altitude were done at the Sports Medicine Center at the Mammoth Lakes Hospital at elevation 7800 feet. They were very similar, using their own CompuTrainer and my road bike with the power steps also being 30 watts. The interval duration was two minutes, making for a quicker but no less painful test.

The key measurement obtained during the test is the maximum amount of oxygen that you can utilize at any point during the test which, as expected, occurs very near the end of the test. This quantity is expressed in liters per minute (l/min). In reporting the result of the test the most common number that you see in the literature is when the maximum consumption is normalized by dividing by the body weight in kilograms and using milliliters instead of liters, coming up with a number like 48.3 ml/kg/min. The reason for dividing by body weight is to make readings more comparable between larger and smaller riders. However for the tests such as I was doing it makes more sense to use a single body weight so the results aren’t affected by small weight variations over the span of a few days which are most likely nothing more than slight hydration differences. My actual weight was taken each test day but I’ve used the average of those four weighings as my body weight in calculating my VO2max values in ml/kg/min.

A few comments about these results. When I did my first test at altitude I told the tester, Tim Tollefson, that my sea level test had been 51.3. He said that people typically test 8 to 11% lower at Mammoth’s elevation. Before I even started the test he predicted that I’d test at about 45 ml/kg/min. As you can see his estimate was right on the money.

My absolute improvement after four weeks of training at altitude was fairly small, only 0.9% at altitude and 1.6% when I came back to sea level. That was perhaps a little disappointing to me but it’s worth noting that I was already highly trained when I went to altitude and it’s known to be difficult to increase VO2max from an already high level.

For some indication of what a high level I was already starting from I include two different tables of ranges of VO2max for people of different ages. The tables include data only up to age 69 in one case and 65+ in the other whereas I’m racing age 74. Obviously these tables aren’t oriented to VO2max values for elite athletes but my VO2max of 51.3 ranks “High” (top group) for age 30+ on one chart and “Excellent” (top group) for age 36+ on the other.

The Mammoth Sports Medicine center also does lactate threshold testing. I didn’t do that test but they did take a lactate reading before each of my tests and again within a minute after the test was over. Those values are tabulated below. The post-test lactate values of 15 millimoles per deciliter indicate how deeply you’ve gone anaerobic by the end of the test.

3-Minute Max Effort Tests

As I mentioned before both coach Dan and I consider field performance tests more informative than lab tests. I wanted to use a field test that could be done weekly that was demanding but not so demanding that it adversely affected my ability to carry out the regular workouts assigned by coach Dan. I settled on an all-out 3-minute effort as being long enough to test my endurance and also to measure my top end power but not so long that there would be a lot of carryover fatigue. Also my racing emphasis this year and next will be on the track and, more specifically, on the 2K individual pursuit. In competition that takes me just under three minutes to complete so the 3-minute max effort test is also good training for the pursuit.

I did my first sea level 3-minute test on my time trial bike on Alpine Road on a section having a 2% grade just before leaving for altitude. My typical pattern for these tests was, from a rolling start, to do about the first 30 seconds standing in a fairly high gear, settle into the aerobars and a lower gear and then, maybe, stand again in a higher gear for the last 15-20 seconds if I had enough energy left to do so.

For the tests to be comparable to one another it was important that they be true maximum efforts. That’s not so easy to do when you’re just doing the test by yourself with no external motivation (no teammates, no cheering crowd!) but I found that I was able to do it, especially the tests near Bishop. I was so wasted at the end of three minutes that I was absolutely, desperately, gasping for breath. On a 6-20 point RPE scale (Rating of Perceived Exertion) these efforts rated a 20.

The next four tests were done at 4550-foot elevation near Bishop. The section of road that I used was smooth asphalt with a 1% grade. The sixth and final test, after getting back to sea level, was again done on Alpine Road, identical to the first test. The table below summarizes the results of these six tests.

The column “Altitude Adjustment” needs some explanation. It’s well know that the power in watts that one is able to produce on the bike is reduced as you go to higher altitude. There are some formulae in the technical literature to estimate the amount of power reduction as altitude increases from sea level. I’ve selected two of these formulae and averaged their results to give an estimate of power reduction at 4550-foot elevation. That number turned out to be 4.71%. Thus the column “Equiv. Watts Sea Level” is obtained by dividing the measured watts by the adjustment factor = 1.0000 – 0.0471 = 0.9529.

The two formulae that I used are:

Peronnet - Canadian J of Sport Science 14(2):93-98, June 1989

y = -0.003*x*x*x + 0.0081*x*x – 0.0381*x + 1.0 (Cubic polynomial)

Bassett – Medicine and Science in Sports and Exercise 31:1665-76, 1999

y = (-1.12*x*x – 1.90*x + 99.9)/100 (Quadratic polynomial)

In these formulae x is the altitude in kilometers and y is the adjustment factor. As a decent rule of thumb the Peronnet formula says that power is reduced by close to 1% for each additional 1000 feet of elevation gain.

It was experimental error on my part to use my road bike for the first 3-minute test at altitude. The road bike handling is different enough from my time trial bike that the results between the two bikes are not directly comparable so I’ve ignored the result of that first test.

The next three tests show a nice progression of the power that I was able to produce. My adjusted power after 9 days at altitude was exactly equal to my baseline sea level power. After 18 days at altitude my adjusted power was 4.2% above my baseline sea level power. After 29 days at altitude my adjusted power was up 8.8% compared to baseline. When I repeated the sea level test my power was up an absolute 27 watts or 9.0% compared to baseline. It’s gratifying that the last test at altitude and the repeat test at sea level gave such closely comparable results (8.8% and 9.0% increase in power).

It’s of interest to point out that though one loses power at increasing altitude, the thinner air is easier to punch through (lower air resistance). These two opposing effects work against each other and it’s not obvious a priori which effect is greater. Does the lower power slow you down more than the thinner air helps you? Or vice versa? The answer is that the thinner air increases your speed more than the lower power reduces your speed up to a surprisingly high altitude. The graph below shows this effect. The altitude of maximum benefit is an amazing 13,000 feet. This partially explains why most American time trial records have been set at altitude at Moriarty, New Mexico and at Sattley with Sattley at 4900 feet and Moriarty at about 6200 feet. This also applies to track records with the velodrome at Colorado Springs at 6100 feet. This effect is not a small one, being about 5% at Sattley and 9% at the velodrome in La Paz, Bolivia.

Note that the above effect applies to riding on level terrain at altitude. For climbing the loss of power at altitude hurts you more than the thinner air helps you. This is just because at the much lower climbing speeds aerodynamics isn’t as important as power.Blood tests

My health care plan is with Kaiser so I had my pre and post altitude blood tests done there. The CBC test (Complete Blood Count) includes most of the blood parameters that I associate with athletic performance. The table below gives all the pre and post altitude values with percentage change between the two. WBC is White Blood Cell count, RBC is Red Blood Cell count and MCV is Mean Corpuscular Volume. Note though that RBC is expressed as million cells per microliter. This is a per unit volume measure and is the concentration of RBCs, not the total number of RBCs.

As is usually the case the hematocrit value is three times the hemoglobin value. None of the changes are dramatic. There’s a 2.2% increase in hemoglobin and hematocrit. The result that initially puzzled me the most was the decrease in red blood cells. That’s the parameter that I thought might increase the most. However what might be the case is that my blood plasma volume increased (possibly substantially?) by a greater amount than the red blood cells increased, resulting in a decreased concentration of red blood cells but not an actual reduction in their total number.

A couple recent technical papers on altitude training use as their key blood parameter a value that I’ve not seen before in the technical literature. They monitor total hemoglobin mass. I didn’t realize that it was possible to measure that but it makes sense to me that it’s a good parameter to use in an altitude study.

The technique for measuring hemoglobin mass is unusual. The test subject re-breathes a low concentration of carbon monoxide gas (CO). Of course breathing carbon monoxide can be fatal! Such a low concentration is used in the test that it’s not dangerous. The CO binds with the hemoglobin. A blood sample is then drawn and measured. The total hemoglobin mass can be determined from the amount of bound hemoglobin. Later I reference two recent papers that utilized this technique in their altitude training experiment. Of course I had no access to such a sophisticated measurement in my study.

The nice thing about measuring total hemoglobin mass is that it inherently includes the effect of increased plasma volume – a key parameter that my limited blood data has no way to address.
Basic Parameters

I monitored daily my weight, morning heart rate, blood pressure and oxygen saturation. The weight, HR and BP didn’t vary much over the period of this study. Averages and standard deviations are tabulated below.

Oxygen saturation is a little more interesting. This measurement is done with a pulse oximeter. I bought one of these inexpensive devices on a Groupon deal. You insert your index finger and it measures your heart rate and the percentage of oxygen saturation in your blood. The values that I got varied only slightly at a fixed altitude and are tabulated below with a picture of the device. The reduced oxygen saturation at altitude plays a role in the reduced power that you experience there.

Summary and Conclusions

How can one draw any conclusions from a study with just one test subject? A common and legitimate criticism of many of the published technical studies of athletic performance is the small sample number of test subjects used in the study. On top of that, when reading these studies, even ones with a reasonable number of subjects, the question in your mind is immediately “Do these results apply to me as an individual?”. It’s seldom possible to perform on yourself the experiment described in the study.

I don’t claim to draw any general conclusion at all from this study but some of the results are at least consistent with similar studies done about the effect of altitude training.

There was an article in the September 2011 issue of Velo magazine on preparing for racing at altitude. The author, Adam St. Pierre, said “In an ideal world you would arrive 28 or more days prior to the event. This would give your body ample time to acclimate (you would receive hematological and non-hematological adaptations). Three weeks is good too, but the increase in red blood cells will be about half of what you’d experience in four weeks.”

This claim piqued my interest and I inquired of the author the source of the 3-versus-4 week benefit. He responded as follows.

“That figure was presented by Dr. Jim Stray-Gunderson at an American College of Sports Medicine Conference in June 2011. In three weeks of altitude exposure, athletes saw a 4% increase in RBCs. An additional week brought on an 8% increase. Dr. Stray-Gunderson has worked with the Norwegian and US XC ski teams in their use of altitude camps to enhance performance. I believe this data was his unpublished observations working with those athletes. I’m sorry that I can’t site a specific research study for you, but Dr. S-G is a very credible source.”