VO2Max Test #4
My head has been spinning since I got this test done and not just because it was a near maximal effort :-) . This was my fourth VO2Max test over the years. I first found this special kind of pain back in 2014 and it was fascinating. The conversation with the faculty member from a local college that administers the test is worth the cost alone. I learn more from him every time we talk. This time around my motivation to get tested again was that my legs seem to fatigue differently. I don't get the same weak feeling I used to have with a hard effort. I've had 3 runs this month where I was able to sustain high heart rates longer than expected. I didn't know if something would show up in the test, but I figured it would be worth a try.
For those that don't know, a VO2Max test is ideally done in a lab where you will run (or bike) with a facemask attached to a computer. As the test progresses, the speed and intensity is regularly increase until you give up. I've never made it past the 3 minute segment of running 7.5mph on a treadmill at 10% incline. The computer reads how much oxygen you inhale and how much carbon dioxide you exhale continuously until you give up. These measurements can be used to determine a few different things.
- At a given effort,
- How much energy is coming from fat?
- How much energy is coming from carbohydrates?
- Ventilatory Threshold Heart Rate
- Roughly equivalent to Anaerobic Threshold
- Max HR
- But only if you are willing to push hard enough, long enough. I didn't.
- Max Oxygen Volume per minute
- Again, but only if you are willing to really suffer
All of the above information can be really useful to craft an effective training plan, but that isn't the question I was trying to answer. I really just wanted to see how my body compares with prior years and to try and get a peek under the hood to see how/what/why I'm able to sustain harder efforts for longer durations.
In this year's test I lasted the longest, had the highest absolute oxygen volume and my second highest VO2Max value. However, the Respiratory Exchange Ratio was the piece of data that would be the most fascinating. When the RER value is 0.70 you are essentially burning only fat for fuel. When the RER value gets to 1.00 then you are essentially using only carbohydrates for fuel. Why does this matter? The biological waste products of burning carbohydrates for fuel need to be cleared from our blood stream. When the effort gets hard enough, our bodies will not be able to clear these waste products as fast as they are produced. When this happens, the bear has jumped on your back and you won't be able to run much faster or for much longer. Dammit bear. Ideally, a VO2Max test would end after reaching an RER greater than 1.00. How can that be possible? It is a side effect of the body producing sodium bicarbonate to buffer the waste products that are generated when carbohydrates are turned into energy (ATP). I don't have a great history of sticking with the test to get to this point. The tube that connects the face mask to the computer prevents me from being able to completely empty my lungs when sh!t gets real in the latter part of the test. Eventually, after a minute or so of not exhaling completely it starts to feel like an asthma attack. I've never had an actual asthma attack while getting one of these tests, but it does make me want to stop.
Ok, with all of that background out of the way...Why was the RER the most interesting data from the test? In the latest test I lasted almost 1 minute longer than my best result from 2014. When the 2020 test ended I was at a lower value for RER (0.97 vs 0.99). So what? Well, those numbers are close together but if you look at the chart below and visualize a trend line it is pretty clear that I still might have had quite a bit of additional time before I would have gotten to the 2014 number. I lasted about 8% longer but have been left wondering just how much longer I could have gone. In all honesty, I fell into an expectations trap. I thought this test would go well and had set myself a goal to last 1 minute longer than my best test, thinking that would be enough time to get all of the data. I was wrong.
Additionally, and this is probably the most important point about the RER data, the red 2014 line is pretty consistently above the blue 2020 for the entire set of 2014 data. There are only a couple of reasons that this would happen that I know of. One possibility is that my body has become better adapted at burning fat for fuel. The other possibility is that my body has gotten better at handling anaerobic waste products. Handling anaerobic waste products better could be that I am better at producing sodium bicarbonate to buffer the waste or even that I've become more readily able to actually metabolize these waste products to create energy (ATP) as a third fuel in addition to fat and carbohydrates.
NOTE: The 2014 data was graphed from 30 second samples. The 2020 data was from 10 second samples. This is why the 2014 data looks smoother and the 2020 data more jagged.
Below is a graph of the respective HR data from the two tests. Now, the blue 2020 HR data is generally higher than the red 2014 data although as the test continues the gap gets narrower. I reached the Ventilatory Threshold (think Anaerobic Threshold) 20 seconds later and at a heart rate 6 bpm higher than in the 2014 test. This shows that I'm able to sustain higher heart rates for longer in endurance efforts, like a marathon, without getting into trouble. If I can stay healthy it will be very interesting to see what happens at the Boston Marathon this year as the data would indicate that I should now be able to race with an average HR of ~6 bpm higher and while that might not seem like a lot, that could easily translate into an average pace that is quite a bit faster. Exciting times!
Strength Training???
So, why can I go farther faster? I don't know, but the person who administered the test quickly focused in on the strength training that I've been doing. I really like this theory, but I still long for the missing pre-Chicago data so that it would be a more conclusive conclusion. His thinking was that strength training is an inherently anaerobic activity. I've added a lot of strength training with physical therapy, Body Pump and heavy lifting. Therefor, the strength training has helped me move the needle in a positive direction. I love this theory because it confirms that what I was trying to do worked out. I just hope it is true!In our conversation, we spent a lot of time talking about the different kinds of strength training that I'm doing and imagining how each might be impacting my abilities. One of the most interesting parts of this was his thoughts on Body Pump classes. Body Pump is a 1 hour class with weights that is very high reps. For example, when we are working biceps the lifts will vary but biceps are typically worked for 6 straight minutes. I typically finish a set like this feeling completely spent. His theory was that these classes are providing a stimulus that has helped my body improve at buffering anaerobic waste products. A particularly interesting part of his thoughts was that since anaerobic waste products are within the circulatory system and shared throughout the entire body that a training stimulus to muscles that are of limited use during running, like biceps, might still help me be able to run farther and faster. The thinking is that the anaerobic weight lifting stimulus to these secondary muscle groups could be a key component to why I seem to be well adapted to harder efforts. To his credit, he shared that he is aware of no academic study that has addressed this question so at this point it is just a thought, but a very intriguing one indeed.
Another focus of our conversation was on what I've been calling "heavy lifting". When I described the routine, which is typically dominated by 4x10 sets on 30 seconds rest he pushed back that this is not heavy lifting. His opinion was that doing sets of 10 repetitions would be more aptly described as endurance lifting and is likely leading to similar adaptations that were ascribed to Body Pump. He suggested that I should increase the weight and do at most 6 repetitions to maximize neuromuscular changes. Essentially, by lifting heavier (even with less reps) my body will change by creating new neurological connections and as a consequence I'll be more able to directly stimulate and synchronize more muscle fibers to engage in propelling me forward on the bike or on the run. I like his thinking, but the idea of lifting heavier weight for less reps makes me nervous. Ultimately, if I do take this suggestion it will likely be an additional periodization where maybe I continue to do 4x10 sets for three weeks and then switch to 3x6 sets for three weeks and then repeat.
Training Volume???
The reality is that I got faster before I ever started lifting weights. I like the analysis above and I believe that strength training is the most likely reason that I can sustain harder efforts for longer but there has to be more to the story. Coincident with getting faster at 70.3/26.2 this year my overall training volume went up substantially, I cleaned up my diet and I lost 30 pounds. While those PRs are now 3 months old, the two VO2Max tests that have been compared in this post both conveniently happened around the same time on the Calendar. The recent test was in late January. The 2014 test was in early February. So fortunately we can pretty easily compare the overall training volume for the 12 months prior to both tests
As you can see above the training volume in the last 12 months dwarfs the amount of training that happened prior to the baseline 2014 test. You can also see that the training volume was especially high in the months leading up to the big 70.3/26.2 PRs last fall.
Conclusion???
Overall, I think this test helps affirm the path that I am on. That path is one where I am focusing on high training volume that includes strength training during the first half of the 43 week training plan. Once the spring marathon season is complete I'll switch over to even higher training volume, especially on the bike, for much of the remainder of the plan. As the race date for the 444 gets closer volume will come down and intensity will increase judiciously in an attempt to get to the start line healthy and with peak fitness.
