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VO2max and High Altitude

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6/10-6/14/06

A forumite, jjcate (Jeff), posted a question concerning the effect of VO2max on racing at altitude. He had recently run a 10k race at 5300’ altitude in which he expected to run in the 44-45 minute range. However, he surprised himself and won the race in a time of 42:00. He posted an inquiry on the Running Times forum concerning whether recent VO2max training might have been a significant factor in his “break through” performance. The following is his post and a dialog he and I had over the ensuing two days, plus additional comments posted by another forumite, ExPhysRunner, a couple of days later.

 

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6/10/06

 

I'm still trying to interpret what to make of my unexpected time at the Idyllwild 10K last week... not so much the victory, as much as running faster than I thought I was capable on hills at 5300'. I'm wondering if I did well because I've been doing workouts that really strengthen my Max VO2 (specifically 800m reps). The altitude didn't seem to affect me at all, even though I live and run at 1500'.

If this is true (that the Max VO2 workouts) are going to make me a better runner in the thinner air, I want to make sure I prioritize them (along with the long run) for my run at the Crater Lake Marathon (6000'-7900') this August.

 

Jeff

 

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6/11/06

 

Interesting question, Jeff.

First, let me say that I have zero experience running at altitude. I did some training and ran one 10k race in Riyadh, Saudi Arabia while visiting there for a few weeks in the middle of a marathon program. But that was only at 2100' and the experts say that altitude up to 1200m (about 4000') has essentially no effect on running. I know that I felt no difference running in Riyadh vs. at home in Maryland. ExPhysRunner, who lives and trains at altitude and makes his living in the field of exercise physiology, is much better qualified to answer your question than I am, and maybe he will chime in. But, I will take a shot at it.

Let's start by looking at a few facts concerning your situation. The only reference I have available to attempt to judge your current 10k potential, in order to relate it to your Idyllwild time, is your performance at St. George last fall where you ran 3:11:50. According to Merv's calculator, that equates to a 41:06 10k. Glover's race equivalency chart indicates 40:48. McMillan's calculator yields 40:53.

Although the Idyllwild 10k is run at 5300', St. George is also run at altitude.....starting at 5200' with the first half run at 4500' or higher. The elevation drops hugely in the second half. But, as you know, that can be a challenge in itself. On average, St. George has a somewhat lower altitude than Idyllwild, but by only about 800' (250m) and most of the course is at altitudes high enough (above 1200m) to affect performance.

However, St. George is a point-to-point course with a significant elevation descent. That makes it less than ideal as a basis for predicting a 10k time run on a loop course with a very tough elevation climb spanning more than a third of the course, such as the Idyllwild course. I would expect that a time run at Idyllwild to be somewhat slower than a St. George "prediction". The question is how much slower? More than the approximately 1-minute slower than St. George predicts? Maybe....maybe not.

It certainly depends on your relative 10k conditioning at Idyllwild vs. marathon conditioning at St. George. I know that you have been training hard and should be very well conditioned now. It's true that your excellent Idyllwild race came at the end of a very hard week. But, that just might indicate that, as the calculators imply, you might have been capable of running an even better time than you did if you had the luxury of a 2-3 day taper.....you really don't need much more than that for a 10k.

There is another variable that might also be a factor in why your Idyllwild time was only a minute slower than the St. George prediction. Running at altitude affects marathon performances as much as 50% more than 10k performances. The longer the time required to complete a race, the greater the percentage deviation from a sea level performance.

Both Daniels and Noakes include graphs in their books that depict the percentage of performance reduction at various altitudes as a function of race time. At 1600 m (about the average elevation of Idyllwild) performance is reduced by 3% for a 40-minute race. At 1350m (about the average elevation of St. George) performance is reduced by 4.25%for a 3-hour race. That's a difference of 1.25% between the two distances. Adjust your St. George time by 1.25% to 3:09:25 and you get a 10k prediction of 40:30. That would make your Idyllwild performance 1:30 minutes slower than a St. George prediction.

I would not credit a focus on VO2max specifically for your "surprising" performance at Idyllwild. I would credit the totality of your training program. You clearly are in better condition than you were three years ago and should have run Idyllwild faster than the 44:39 you ran then.

Basically, I think you are in better condition than you give yourself credit for and can look forward to some excellent racing for the rest of this year....both at altitude and at sea level

Concerning the Crater Lake Marathon, Daniels’ and Noakes’ graphs indicate a 6% performance reduction at 2000m (6562') and 8% at 2500m (8202') for a 3-hour race, relative to sea level. You probably should factor in about a 7% average reduction.

One last comment. Noakes says that the reduction in VO2max that occurs at altitudes above 1200m is most prominent beginning the second day after arriving at altitude. He says the sea-level athlete (below 1200m) should compete either immediately upon arriving at altitude (drive to altitude on race morning) or 3 or more weeks after arriving at altitude. He also says the worst time to race at altitude is within 3-6 days after arriving at altitude.


Jim2

 

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6/12/06

 

All the information you provide is very, very helpful, but two items especially were items I had not considered...

1) the fact that thinner air affects longer distance races more than shorter distance races. That had not crossed my mind. The information you provide from Daniels and Noakes is very helpful. I think you're right about an average 7% reduction in expected performance. My marathon performance at Crater Lake will be more affected by the thin air than my Idyllwild 10K (even if they were at the same altitudes).

2) when I arrive at altitude. Unfortunately, I'm going to end up doing it the wrong way according to your information. I'll arrive on a Friday morning, race on Saturday morning and then fly home on Sunday evening. So I'll end up racing the second day I'm there. I didn't really have a lot of other options on how to schedule this trip. I'll be going by myself and it's hard to squeeze this trip in with a family and a full-time job. (Basically, I'm just using the plane ticket I didn't get to use to go to Boston before it expires, but I love doing the tough scenic marathons so that's why I picked this one.) Fortunately, I'm not concerned about a PR or winning the race, but I do want to give this race my best performance possible.

The reason I wondered about the Max VO2 was because I was wondering if I focused on this, if my body's increased ability to process O2 would help me in the thinner air.

BTW, I didn't know that about ExPhysRunner. Thanks for mentioning him as a reference for these types of questions.

Thanks again for a very helpful and detailed response. As always, I can tell you put a lot of time, thought, and research into your response. I really appreciate that. BTW, this information will be helpful for me beyond this Crater Lake Marathon as well. I'm hoping to run the Leadville Trail Marathon a year from now (I'd do it this July if I could fit into my schedule). That's the highest (cumulative) elevation marathon in the country. Even though the high point is 13,180' (about 1000' lower than Pikes Peak), the entire course never goes below 10,000'. Now for that one, hopefully, I can spend a couple of weeks at my in-laws in Fraser, Colorado (9500') acclimating at the end of my taper.

BTW, on another matter, when I think about my PR's for shorter distances (5K, 10K) vs. longer distances (half marathon, 30K, marathon), my longer distance PR's seems soft (or not as fast) as what should be expected by my shorter distance races. This was true in my late 20s and now in my late 30s. I've often wondered if this is because I have a higher max HR. I don't wear a HR monitor anymore, but when I was 28 and 29 I did. A few times then, I saw my HR hit 203 (when it should have maxed out at 192 or 191 based on 220-age). I easily went over 191 when I would run any number of repeats (whether 400m or 800m) or even at the end of a hard tempo run. Since it seems I have a higher max HR (which acc. to Pfitz is genetically determined and can't be altered by training), that would seem to benefit me more in shorter distance races than longer distances (or maybe I'm wrong). I'd be curious your thoughts on this matter.

 

Jeff

 

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6/12/06

 

Once you have trained (including speedwork) consistently for a year (even less for many runners), VO2max should be maxed. Then, as long as your continuing training program is balanced (and yours appears to be well balanced), you will maintain VO2max, and you can't drive it any higher by focusing on more VO2max interval workouts. The only way increased emphasis on intervals will improve VO2max is if you have let your VO2max degrade by ignoring intervals and short distance racing for an extended period of time.

Although you can not increase VO2max beyond your genetic limit, you can improve vVO2max....the velocity (pace) at which you reach VO2max. That occurs as you become a fitter and more economical runner through continued training.

Whatever your VO2max is, it will be reduced at altitude, and your training can't alter the reduction. It just determines the level of VO2max that you take to altitude.

The reduction in performance at altitude is due to the decrease in VO2max. The air is less dense, but that isn't the main cause of VO2max reduction. It's due to the decrease in atmospheric pressure. More oxygen is taken into the lungs than can be transferred to the blood whether at sea level or at altitude. (Except at very high altitudes.) However, decreased atmospheric pressure reduces the amount of oxygen that becomes attached to hemoglobin in the blood. Hemoglobin is the vehicle that transports the oxygen to muscles. With less oxygen attached to hemoglobin, then less is delivered to muscles, which impairs performance.

You are far from alone concerning "soft" longer distance times vs. those of shorter distances. Many runners find that race calculators predict faster marathon times than they actually run. Some claim that the calculators are wrong. And they are right, in a way. Today's calculators are based on algorithms that are as much as 30-years old and that assume highly trained marathoners (read "high mileage"). Generally, they seem to be most accurate for those who run 70+ miles/week and less accurate for those running less mileage. If you are interested, I wrote a very long post on this subject three years ago titled "Predicting A Marathon Time" that is archived on my Running Page at http://mysite.verizon.net/jim2wr/.

I don't know that an unusually high HR would translate to better short distance performance vs. longer distances. It might be an indication of an exceptionally high VO2max, which, like HRmax, is also genetically determined. In fact, they are linked. The higher the HR, the more oxygen can be transported to muscles since the heart is able to pump a greater volume of blood/minute. But max is still max....whatever that is for you.

I think that a high HRmax and VO2max would affect all race distances proportionally, since race intensity for a particular distance is generally a percentage of VO2max. Maybe your obviously good performances at altitude at both marathon and 10k distances are indications of that.

I think the main physiological factor that affects marathon performance vs. that predicted by shorter distance races (especially a 10k) is running economy. Improving running economy will also benefit performances at all distances. However, the longer the distance, the greater the impact of improved running economy because of fatigue and fuel utilization rate factors that come into play more at the longer distances. Being able to run longer at a given pace or faster at a given intensity level on less fuel and with less fatigue is certainly more important in a marathon than in a 10k.

Runners with relatively low VO2max, compared to their peers, have been known to excel at long distances (such as the marathon) vs. short distances because of superior running economy. Generally, the more economical the runner, the better the correlation between predicted and actual marathon times, regardless of VO2max.

In fact, highly efficient runners can perform even better than a predicted time. One example is Alberto Salazar. His marathon PR of 2:08:13 is 2 1/2 minutes (2%) faster than predicted by his 8k American record of 22:04, which still stands today more than 20 years after he set it. And Salazar's VO2max measured relatively low for an elite runner....lower than that of Gary Tuttle, Craig Virgin, Bill Rogers, and Don Kardong, none of whom were able to run a marathon as fast as Salazar.

Salazar, Frank Shorter and Derek Clayton....all champion marathoners....were well known for their superior running economy. And all three excelled at the marathon distance over peers who had significantly higher VO2max.

I think that improving running economy brings marathon performances more in line with the predictions of shorter races, regardless of HRmax and VO2max. The ways to improve running economy are increased training mileage, weight training for improved muscular strength, and repetitions that are faster and shorter than VO2max intervals.


Jim2

 

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6/14/06

 

Sorry I am late in coming to the party. I have been busy and off this board for a while.

I cannot add much to Jim2's comments in terms of the physiology of altitude (at least nothing that really matters).

So consider these sort of random thoughts:

1) A given altitude will affect everyone differently so do not put a lot of weight into any % decrease. Also where that becomes an issue is going to vary. Some folks will not see a decrease in performance until they go much higher than another person. To take a famous example, a certain cyclist has been tested in Austin (200m?) and in Colorado Springs (1860m) and the decrease in VO2max was much smaller than predicted. Why? Who the hell knows! We are humans.

2) Perhaps 5300 feet is below your "impact threshold" where the decrease in PO2 is just not going to have as big an impact. Why? Again, who the hell knows!

3) Did you have low expectations so surpassing them was easy?

4) Maybe you were just in good shape so that the performances off of which you were predicting were soft?

5) As for VO2max workouts, if you were able to raise your VO2max (or vVO2max) then you are working from a higher ceiling. So rather than having a decrease of X% from 60 ml/kg/min, you were X% of 65ml/kg/min (or whatever it might be).

6) 5300 feet is not all that high in reality (I say from my desk that sits at about 6200 feet!). Again, it might just not be high enough to affect you as much as a higher altitude will or would affect another person.

7) I would not do anything drastically different in prepping for the marathon. VO2max is not going to be the deal breaker as much as it is at shorter distances. Also, if you are running well enough to win races then I am guessing you are pretty close to optimizing VO2max and spending extra time on those workouts might not be the best use of time.

8) Check the barometric pressure. It is the partial pressure of the O2 that matters and that is related to the total air pressure. So if a high pressure front moves through, it can really help you since the "effective" altitude is actually lower. The reverse is seen in acute mountain sickness where a low pressure front coming through means that the ski area ERs order extra O2 tanks as they are going to see more sick folks. It can make 11,000 feet be more like 12,500 feet (depending on the severity of the low pressure front). So in the marathon pray for a high pressure front!

 

ExPhysRunner