In 2005, three friends and I went to get our first VO2 max tests. Without any training knowledge, I didn’t know what the results meant. Fourteen years later, that first test is a good benchmark. I can make some unfortunate conclusions, especially when including two more tests that bracket a period of intense skimo training.
First, some geekery. As you can see from the chart below, between 2005 (at age 31), 2013 (at age 39), and 2019 (at age 45):
- My aerobic, anaerobic, and VO2 max threshold heart rates only changed by one or two beats;
- My absolute VO2 max declined by 11% and then increased by 4.6%. It’s still 7% below my 2005 value;
- My anaerobic threshold pace declined by 6.9% and then increased by 21%. My 2019 AnT pace is 12.4% above 2005; and
- My aerobic threshold pace declined by 9.3% and then rebounded by 27%. My 2019 AeT pace is 15.5% above 2005.
What do these tests mean?
While looking at the chart and thinking about my training history, I can make a few conclusions:
Changes in heart rate are low-hanging fruit
Despite several active years, my threshold heart rates haven’t changed. On my first VO2 test, my aerobic and anaerobic threshold heart rates were within 5% of each other. Today, they’re just under.
I suspect that changes in threshold heart rates are an early stage change. Typical of early stage changes, they may be quick, but not significant in the long-term. Any improvement likely happened between 1999 and 2005 when I was ice and alpine climbing.
I undertrained in my 30s
I had significant demands on my time in my thirties. I was running a business and starting a family. Sport climbing was the easiest thing to fit in. I never rock climbed better, but it didn’t do much for my aerobic fitness.
Between 2010 and 2013, we had our second child, and I started working for a software company. My schedule was flexible. I could work and stay home with our youngest son, but I didn’t do anything physical for three years.
Proper endurance training increases aerobic capacity
The increases in threshold paces came via a thorough education in endurance training. My friend Scott Johnston answered hundreds of questions and gave me lots of good advice. He told me what books to read. That knowledge was a huge help when setting up my training program.
In particular, I made several changes to my training program in 2018. That allowed for a much greater training volume and a lot more intensity. I suspect that the biggest increase in my threshold paces happened that year.
VO2 max isn’t a big factor in performance
Between 2013 and 2019, my threshold paces increased by significant amounts. My increase in VO2max was much less.
For a long time, physiologists have known that VO2max isn’t the best predictor of performance. But the popular press won’t give it up. It’s a sticky idea that’s easy to grasp. Much easier than the complexity of endurance training.
Not only did my VO2 not change that much, but it was never world-class to begin with.
…unless the relationship between VO2 max and threshold paces is non-linear
Could it be the case that a 1% increase in VO2 max equals a ~5% increase in anaerobic threshold and a ~6% increase in aerobic? If that relationship holds, then it would explain the pace changes that I’ve had in the last six years.
But… if I had trained in my 30s, and my VO2 max was 7% higher, would my anaerobic threshold pace have been 35% faster than it is today? And my aerobic threshold pace, 42% faster?
I have no idea, but I doubt it. Those increases seem too good to be true.
I’ve finished my short-course skimo experiment. It’s not something that I want to repeat, especially something like this past season. Staying fast over three months of races is exhausting. Not only physically; the mental fatigue is huge.
But loss aversion is a powerful force. I have a lot of training knowledge, and I’m 45. The knowledge shouldn’t decay, but my potential will. I have, at best, another five years where I can make gains. Then an age-related decline in endurance is almost certain.
I’m sure the gains that I could make are quite marginal. I doubt I could spend the next five years training and add another ~20+ percent to my threshold paces. If improvements occur, they’ll likely be in the low single digits.
Are marginal gains worth the significant training volume required? That’s the question that I need to answer.
More important than any increases in speed, I need to decide what to apply them to. Without an inspiring pursuit, I wouldn’t be able to sustain the motivation to make those gains.
Long-course skimo racing is appealing, as is cycling and getting back to rock climbing. However, I couldn’t ask for three more conflicting sports… Maybe an impossible balancing act will be the next challenge.