The test I expected to understand
Eight weeks after the first treadmill test, I went back for the retest.
The first test had been a shock. It showed a VO2max far higher than Garmin had ever estimated, and at the same time almost no real aerobic base. Huge engine, poor chassis. The prescription was obvious, even if emotionally annoying: slow down, build the base, stop turning every easy run into a secret threshold session.
So I did the work.
From November to March I had done no real quality training. Then, after the first test, I spent the next block trying to follow the new structure. More controlled base, some mixed work, some intervals, a more conscious attempt to train the system instead of just chasing numbers.
I expected the retest to be simple.
VO2max up. Thresholds shifted. Lactate curve cleaner. A neat little redemption story.
That is not what happened.
The confusing result
The second test reported VO2max at 61.7 ml/kg/min.
The first test had reported 65.9 ml/kg/min, but that number was calculated using 84 kg. My actual weight that morning was closer to 82 kg. With the original absolute VO2 of 5536 ml/min, the corrected relative number is closer to 67.5 ml/kg/min.
So the real comparison was not 65.9 to 61.7.
It was closer to:
67.5 to 61.7.
That is a large drop.
On paper, that should have been depressing. Five months earlier, after doing no quality work at all, I had produced my highest lab VO2max. Now, after structured training, quality work, intervals, and a serious attempt to improve, the headline number dropped.
The obvious emotional interpretation was: what the hell?
The more useful interpretation was: the headline number was not the whole test.
Because the same report also showed something else.
VO2 at AT improved from 48.3 to 55.2 ml/kg/min. AT speed moved from 12 km/h to 14 km/h. Heart rate at most comparable speeds was lower than in the first test. Lactate at 12 km/h was much lower than before.
So the ceiling looked lower, but the usable system looked better.
That is not a clean story. But biology has never promised clean stories. It mostly promises expensive ambiguity.
The number that fell and the system that improved
This is the part I had to sit with.
VO2max fell.
But the ability to use oxygen near threshold improved.
That matters.
For running, especially for a 5k recreational runner trying to build real performance, the question is not only how large the engine is. It is how much of that engine can be used while the rest of the system remains stable.
The second test suggested that I may not have reached the same maximal oxygen uptake because the limiter was not purely cardiovascular.
At 18 km/h, I lasted about 40 seconds. Heart rate reached around 194-195, lower than the previous peak around 199. But the reason I stopped was not breathing. It was not the heart. It was the legs.
At that speed, my running form started to fall apart. I felt I was losing control of the legs. Not tired in the poetic sense. More like the operating system was no longer syncing properly with the hardware.
The person running the test also noticed the same thing: too much energy leaking from the mechanics. The legs were not translating the engine into motion efficiently.
That is useful information.
A VO2max test assumes that the athlete can continue long enough to hit the true oxygen ceiling. But if the test stops because the legs, mechanics, or local muscle endurance fail first, the measured VO2peak may underestimate the central capacity.
That does not mean the number is fake.
It means the limiter moved.
The lactate curve that annoyed me
The strangest part was the beginning of the lactate curve.
At low speeds, the numbers were high:
- 8 km/h: 3.8 mmol/L
- 10 km/h: 3.5 mmol/L
- 12 km/h: 3.2 mmol/L
- 14 km/h: 4.5 mmol/L
- final lactate: 14.9 mmol/L
That curve is ugly and strange because lactate first falls instead of rising.
The lab interpretation was that lactate can be elevated at the start of exercise and then fall as the aerobic system switches on more effectively. That makes physiological sense. The body can clear lactate while workload is still moderate.
But practically, I still had a problem with it.
In real outdoor running, I can run around 6:40/km at roughly 135 bpm. The treadmill test showed 150 bpm at 8 km/h, which is 7:30/km. That does not match my field reality at all.
Maybe the treadmill changes my mechanics. Maybe the mask, lab setting, stress, and lack of natural cooling raise heart rate. Maybe the one minute of skipping rope before the test contaminated the early lactate readings. Maybe all of the above.
The lesson is not that the test was useless.
The lesson is that laboratory data and field data must argue with each other.
When a test says 7:30/km costs 150 bpm, and real running says 6:40/km costs 135 bpm, I do not throw away the test. But I also do not throw away reality.
The Zone 2 argument
The new report gave Zone 2 as 140-149 bpm.
That bothered me.
After the first test, Zone 2 had been 132-138. I trained there and improved. At the same heart rate, my pace moved from around 7:00-7:10/km to about 6:40/km. That is a real aerobic adaptation.
So when the new report told me to run base at 140-149, my first response was resistance.
If lactate is already above 3 mmol/L at low speeds, should base training really sit near 145-149? Is that aerobic base or just another version of the grey zone?
I asked the lab. The answer was clear: zones are not based on lactate alone. They use the full physiological picture: gas exchange, heart rate, ventilation, VO2, VO2 at AT, and the full pattern of the test. The recommendation was to use the new zones, but start from the lower end if I had concerns.
That is where the useful compromise landed.
Not 132-138 as a religion.
Not 149 as a target.
For now, my working base zone is the lower part of the new Zone 2: around 140-142 average, with 145 as a brief ceiling, not a goal.
I tested it.
For one hour I held an average heart rate of 141. When the watch drifted to 144-146, I calmed down and slowed down. The run felt heavier than the old 132-138 runs, but not destructive.
More importantly, for the first time in months, I felt the legs working in the right way.
Not dragging. Not shuffling. Not just moving the body forward passively.
The calves were active. The stride had more drive. The body felt more vascularized afterward. My back felt better. I was not stiff.
That matters.
Because one of the reasons I started running in the first place was not a race time. It was that running makes the body feel alive, open, and supplied with blood. If a run leaves me crushed, it failed. If it leaves me loaded but loose, it worked.
What probably did not work
Looking back, I do not think the previous quality block gave me what I wanted.
The pyramid sessions went too high. The short intervals generated cost, but not much useful control. After the hard middle part, the last segment of the workout always collapsed. I could enter the high zone, but I could not clear it.
That matches the lab result.
The final lactate was high. The tolerance is there. I can suffer. I can enter the red area.
But that is not the same as being well-trained there.
The missing piece is not the ability to produce lactate. It is the ability to stay controlled near the lower end of threshold and recover while still running.
That points away from more brutal intervals.
It points toward stamina.
What this block is now
This next block is not a 5k-specific sharpening block.
It is a general preparation block with a stamina focus.
In McMillan language, this is stamina development: steady runs, tempo work, cruise intervals, tempo repeats. The bridge between endurance and speed.
In Daniels language, this is mostly E plus T, with a little R for mechanics. Easy running, controlled threshold work, and short fast strides with full recovery. Almost no I pace for now.
The goal is not to prove I can suffer.
The goal is to build the zone that did not move enough.
The 10 km/h area, around 170 bpm, barely changed between tests. The lower base improved. The AT point moved. But the practical low Zone 4 / stamina zone still looks underdeveloped.
So the work now is simple:
- base runs at 140-142 average
- one controlled stamina session per week
- no regular 180+ bpm work
- no heroic 45/45 intervals
- short strides for leg speed and mechanics
- deload every fourth week
The quality session will live mostly around the lower Zone 4, roughly 167-172 bpm. Not 183. Not “let us see if I survive.” More like:
- 4 x 5 minutes
- 5 x 4 minutes
- 3 x 8 minutes
Controlled. Repeatable. Finished with the feeling that one more rep would be possible.
That is the opposite of the sessions that made the last five minutes collapse.
What I am taking from this
The first test gave me the dramatic lesson: high VO2max, no base.
The second test gave me a more annoying lesson: adaptation is not linear, and the number I wanted to improve may not be the number that improved.
VO2max fell.
But the usable threshold system improved.
The legs failed before the heart.
The base improved at low heart rate, but the stamina zone still needs work.
And the lab zone may be useful, but it still has to be translated through field data and body feedback.
The mistake would be to choose one authority and obey it blindly.
The lab is not God. Garmin is not God. Feeling is not God either, although it occasionally makes a better argument than both.
The useful answer is triangulation.
The next eight to ten weeks are about building stamina without returning to the old habit of turning every session into a stress signal.
Not more violence.
Better pressure.