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Active Expert: Gale Bernhardt

5 Posts tagged with the altitude tag

For my cyclists that have power meters, I like to use a combination of heart rate and power numbers for some workouts. One reason I do this is to flush out fitness data that would otherwise be hidden. Let me give you an example.

If the assignment is to ride at Zone 2 heart rate (the biological response), the athlete does that workout without regard to power output or speed. This kind of workout has its place in training and I do use it.

If the assignment is to produce Zone 2 power, the athlete completes the workout and typically comments in the feedback section. A comment might be, “Heart rate high (or low) for Zone 2 power.”  Or they might comment, “Workout went well.” In any case I do get information from this workout – and the workout has its place in my mix of workouts.

Sometimes, I use a combination of heart rate and power so the athlete can drive the highest power possible on that day, while limiting the biological cost. Below is a sample workout for an athlete with a current Zone 2 top-end wattage of 135 and top-end Zone 2 heart rate of 136. I wanted an aerobic workout  that produced the highest possible power during specific intervals.


The workout

Do a 10-minute warm-up.

The entire workout is 4 repeats of the following:

5 minutes at ~135 watts (Keeping heart rate 136 or below. If you can push higher watts than 135 for a cost of 136 heart rate – do it.)

5 minutes at 120 watts or less (Zone 1 heart rate)

End with easy spinning at Zone 1 heart rate

One of my athletes (power and heart rate data used in the sample above) recently returned from a ski trip in Switzerland. He skied for six days at an altitude of 3000 to 4000 meters. He lives at sea level. Though he was only at altitude for a week, his results for the workout I describe above showed a marked change. He was able to push wattages much greater than 135 while keeping heart rate low. Important to note, his low heart rate felt low and the effort felt easy. (Sometimes athletes note that a low heart rate feels really hard – i.e. Zone 2 heart rate feels like Zone 3.)

You can see his graph below.

Power after altitude 2013_edited.jpg

(You can select the graph to make it larger.)

Did his time at altitude change his ability to push higher wattage for a low - aerobic - cost? Is this result just part of his increased fitness due to the training mix? (It’s important to note I’ve worked with this person for a few years.) Or, was this workout a performance fluke? (He was able to produce more wattage than what is normal, given this heart rate.)

The questions are reasonable and I’ll continue to monitor his performance to see if it is time to make an adjustment to training zones.

If you are a self-coached athlete, it is important to cross-reference training zone data from time to time to be sure you are getting the most benefit from the workouts. You can get some of this data from testing – but – I believe it is important to sample workout data as well.



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1,005 Views 0 Comments Permalink Tags: altitude, power, heart_rate

In the last blog I mentioned that I would cover why I was able to ride within my lactate threshold heart rate range for two hours and forty-five minutes. That’s not possible – is it?


Recapping some of the altitude specifics, the mainstay of my training over the summer was directed at doing mountain bike races between 8 and 11 hours long and at altitudes between 9,000 and 12,600 feet. I live atroughly 5,000 feet. The September race where I accumulated near three hours at lactate threshold intensity was at altitudes between 3,000 and 6,000 feet.


I’ve written a couple of two-part columns that will give you background of altitude affects on training and racing. The first one is “Altitude Training for Athletic Success” and the second one is “Acclimating to Altitude”. From the columns, a couple of key points:

  • Heart rate increases in response to higher altitudes – but you cannot maintain the same speed or power output for that given heart rate at increased altitude. This means that lactate threshold heart rate at increased altitude is lower than your home base.
  • For a given speed or power output at a lower-than-your-home-base altitude, the corresponding heart rate will be lower. (Assuming temperature and humidity conditions are similar.)


To know my actual heart rate training zones for all ofthe corresponding altitudes where I raced this summer, I would need to do a test at each location. Since that is logistically not possible for me, I use the same data collection zones for all altitudes and adjust accordingly – I raced according to my rating of perceived exertion (RPE) for the lower altitude event. This means the data for my race at a lower altitude is not really all within an accurate lactate threshold zone. So no, I didn’t spend near three hours at lactate threshold.


Also recall within the altitude columns that you can produce higher speeds and more power output at lower altitudes. (The reason why the Olympians living in Colorado Springs train with supplemental oxygen sources for sea level racing.)


Sans actual power data, I believe I did not have the training to tolerate the power outputs I was generating at the lower altitude race.  If the neuromuscular and metabolic systems have not been trained for the speed and power outputs (duration and intensity) possible at lower altitudes, then I believe there is a possibility of cramping.



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685 Views 0 Comments Permalink Tags: training, altitude, racing, power, heart_rate, acclimitization, lactate_threhold

Several years ago a buddy and I decided to train for a trail run. As I mentioned in yesterday’s blog, we live at roughly 5,000 feet and the trail run would be at elevations between 4,000 and 8,500 feet. As we began training in the mountains at higher elevations, we both noticed a marked shortness of breath. We believed it was the altitude affecting us.


As we continued training, we both noticed that it seemed that the altitude was bothering us less and less – even though we had just a few hours of exposure each week. Because most literature supports a “stay at altitude for three weeks” format of altitude acclimatization, I wondered if anyone had looked at intermittent exposure.


I contacted Dr. Randy Wilber, head physiologist for the U.S.Olympic Training Center and asked if he had seen anything on intermittent exposure. He said he hadn’t. I asked his opinion on the experience we had with our once-per-week format and he said that though there’s no evidence, he had to believe that some expose is better than none and does offer some form of adaptation.


When I was training for the trail run, I had no way to easily measure whether my weekly exposure was beneficial or not.


As I mentioned in yesterday’s blog, I purchased a pulse oximeter in 2010. Since that time, I’ve taken samples of oxygen saturation (SPO2) at 5,000 feet and at 9,100 feet for myself. Know that this is a sample size of one and the experiment was far from controlled and scientific. That written, here’s what I’ve found:


  • SPO2 at home, 5,000 feet runs 98 most of the time
  • SPO2 at 9,100 feet runs 92 if I have not been at altitude for over four weeks
  • If I have 24 to 72 hours of exposure to 9,100 feet every three weeks, SPO2 runs at 96 (know that I sleep at 9,100 and exercise is most often at higher altitudes)
  • At the end of last summer, when altitude exposure at 9,100 was more frequent than every 21 days, my SPO2 would be between 97 and 98

In summary, for me, intermittent exposure to altitude does help SPO2 and I can feel the difference as well. It's an advantage for me. Though I didn’t collect as much data on pulse rate, I did see pulse rate drop on a track similar to the rise in SPO2. This is good - more oxygen saturation for less work for my heart. 


If you wonder what’s happening to your oxygen saturation when you travel to the mountains for fun, training or racing I suggest picking up a pulse oximeter and taking some measurements. You can get a quality device for around $50.


Let me know what you find ~

1,085 Views 0 Comments Permalink Tags: altitude, pulse_oximeter, acclimitization, acclimation, spo2, randy_wilber, olympic_training_center

For awhile, I’ve tried to determine if repeated short-term exposure to altitude can help with the acclimatization process. This curiosity is geared primarily for people living in a Front Range situation and then doing fun activities, training or racing in the mountains.


To help me determine if short-term exposure to altitude might help acclimatize people so that they can enjoy fun activities, training and racing at altitude, I picked up a pulse oximeter.  I mentioned the pulse oximeter in a 2010 blog. My personal interest in the numbers is for alpine skiing, Nordic skiing, trail running, road cycling, mountain biking and hiking.


A pulse oximeter is a non-invasive way to measure the amount of oxygen the blood is carrying. The number displayed is expressed as a percentage of the maximum amount the blood could carry at 100 percent. At sea level, typical saturation values are 97 to 99 percent in healthy people. At 5,000 feet it might drop to 95 percent and at around 10,000 feet it may dip to 90 percent. Somewhere around 10,000 feet there is a big change and oxygen saturation can drop to 80 percent or below.


Acclimatizing to various altitudes can help improve these numbers up to a point. Know there is individual variability in the acclimation process and there is even variability among native dwellers at any altitude, beginning at birth.


Children born at various altitudes have similar oxygen saturations during the first 24 to 48 hours of life and the values change within the first four months of life. For example, newborns in Denver, Colorado (5,280 feet, considered moderate altitude) have saturation levels of 85 to 97 percent while those born in Leadville, Colorado (10,152 feet, considered high altitude) are 85 to 93 percent.



Though the time periods noted in a medical column weren’t exactly the same, it is interesting to note that after four months, the Leadville infants were between 89 and 93 percent saturation during wakefulness. Healthy, awake infants under the age of two measured between 90 and 99 percent in Denver. So there was some shifting up, particularly on the low end.


You can pick up a pulse oximeter at many local pharmacies. A common use for these devices includes measuring oxygen saturation in people with compromised lung function. Pilots and mountain climbers also use the devices to determine when supplemental oxygen might be necessary to avoid fainting.


I’ve been playing with an oximeter to look at oxygen saturation at my house (roughly 5,000 ft. measured on my Garmin) and Frisco, Colorado (roughly 9,100 ft.) I did this because much of my fun, training and racing is done at altitudes of 7,500 ft. or more and I was curious if my oxygen saturation changed much between the Front Range and the Colorado mountains.


The next blog will be more about what I’ve noticed in my experiment of one.



2,060 Views 0 Comments Permalink Tags: denver, hiking, mountain_biking, altitude, colorado, skiing, trail_running, acclimatization, nordic_skiing, pulse_oximetry, frisco, blood_oxygen_saturation, alpine_skiing, road_cycling

This post is a place to share your personal findings on pulse oximetry data.


I'll gather up a bit more information to post in a week or so, but here is a start:


My home (~5000 ft. elevation) readings (about six days of data  readings) on oximetry ranges between 97-98% for me (96-97% for Del, my husband that does not have asthma and he is not an endurance critter). Arrival to  Frisco, Colorado I was 91-92% pre-asthma meds (Del@ 95%). Same day I was 95% post-asthma meds and post-skiing.


The next morning I was at 94% pre-asthma meds, 97% just 30-minutes post-asthma meds, 93% at 9:30 pm (about 12 hours after asthma meds). The third morning at Frisco, near 48 hours after being at altitude I was bouncing between 96-97% pre-asthma meds. The next two days at Frisco produced the similar results at 95-96%. Returning home, I was pretty consistently at 98% every morning for four mornings. Know that I've been at altitude about once every 21-28 days for the last year. I'm there an average of two days at a time. It would be interesting to see numbers for me about 1.5 years ago before the monthly altitude pops. June of 2009, I really felt the altitude with almost a year of non-exposure I was huffing and puffing going up two flights of stairs. Exercise intensity was quite compromised. 


For this schtick at altitude, Del remainded pretty consistent at 92-95% in Frisco, 95-96% at home. His reduction was less than mine. Asthma? Or just individual differences in tolerance?


Comments or data sharing are certainly welcome here ~

939 Views 1 Comments Permalink Tags: altitude, exercise, asthma, pulse_oximetry