VO2 Max: A 14-year retrospective

Scott Semple

Jun 3, 2019 • 4 min read

In 2005, I went with three friends to get our first VO2 max tests. I didn’t know what the results meant. But fourteen years later, that first test is a good benchmark, and I can make some unfortunate conclusions. When compared to two more tests that bracket six years of heavy skimo training, it’s clear that I was very undertrained in my 30s.

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 changed by <1%;
My absolute VO2 max declined by 11% and then increased by 4.6%. It’s now 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.

A chart showing the changes in thresholds after 14 years and across three VO2 max tests — I had VO2 max tests done in 2005, 2013, and 2019. Before 2005, I was doing a lot of regular but unstructured ice and alpine climbing. Between 2005 and 2010, I was running a wholesale business and sport climbing. Between 2010 and 2013, I did nothing, working for a software company and sitting all day. Between 2013 and 2019, I studied endurance training and competed in skimo racing. In 2019, I attended the ISMF World Championships as a member of the Canadian National Team.

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, I was even busier. 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 which allowed for a lot more intensity. I suspect that the biggest increase in my threshold paces happened that year.

A chart of annual training volume in hours and elevation gain — Annual training volume: The years noted represent the competitive season. For training, those years started in the preceding April and ending in March of the year listed. My annual training was philosophically correct, but unfortunately inconsistent. The last three years were the most productive with a noticeable volume increase for 2019. My volume peaked at 736 hours and just under 229,000 vertical meters.

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.

What now?

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 won’t decay, but my potential will. I have, at best, another five years where I might make gains. Then an age-related decline in endurance is almost certain.

I’m sure the gains that I could make now 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 climbing. However, I couldn’t ask for three more conflicting sports… Maybe an impossible balancing act will be the next challenge.