The neighbor
Over the winter my neighbor’s running started looking strange. He was not really running. He was shuffling, dragging his feet, sometimes dropping into a walk. From the outside it looked like he was injured, or burned out, or had given up. I asked what was up. He said he had done a treadmill fitness test and was now training off the plan they gave him. I filed that away as interesting, in a slightly skeptical way.
I had been considering a test for a while. Not to fix anything. To confirm. My Garmin said my VO2max peaked at 51 last summer and slid to 47 over winter. The plan was simple: rebuild form, get the watch back to 50+, then walk into the lab, get told “great numbers,” and walk out feeling correct. The order mattered. I wanted to be tested at my best, for my ego.
What this plan tells you, in retrospect, is how I had been training for three years. Every run was pointed at a number on a watch. Every easy run drifted up to about 155 bpm because that is where the watch’s VO2max estimator likes you to live. I was grinding for one-point gains. A unit on the watch felt like a small victory. I had the absurd idea that getting from 47 to 50 was the meaningful project of my running life.
Then the shuffler beat me. On a regular training run, not a race, he posted a 5k time better than my personal best. Both his record and mine, in the same session. We used to be roughly equal. So I went and got tested. Earlier than planned. Worse-prepared than planned.
The test
Treadmill, breathing mask, heart-rate strap, blood draw at every stage for lactate. Each stage had to be completed: 3 minutes at 6 km/h, then 8, 10, 12. From 14 km/h the stages dropped to 2 minutes. To “count” a stage you needed at least 1.5 minutes at the new speed.
6 km/h, walking. 8 km/h, still walking. 10 km/h, finally running. 12 km/h, running, fine. 14 km/h, running, no longer fine. 16 km/h, lungs and legs both lodged formal complaints, but I finished.
Then they wanted to push me to 18. I said stop.
This turned out to be a mistake. The protocol holds the new level for 1.5 minutes minimum, and I was certain I could not survive 1.5 minutes at 18. What I learned afterward: even 10 to 30 seconds at 18 would have produced more data, because VO2max was still climbing. The cap I hit was not a physiological cap. It was the cap on my willingness to suffer at that exact moment.
This is a small lesson in itself. In a test designed to find your ceiling, declining to find it is not modesty.
Shock one: the engine
VO2max came in at 65.9 ml/kg/min on the report, and they used 84 kg as my weight. Actual weight that morning was 82. Recalculate: roughly 67.5.
For context: Garmin had me at 47.
That is not a small delta. On YouTube, when people film themselves doing the same kind of lab test, the typical correction relative to a watch estimate is something like minus two. The lab usually pulls the watch down a little. Mine went the other way. Plus twenty.
I sat with that for a while. For three years I had been grinding for single-point gains on a watch that was, apparently, off by twenty in the wrong direction. The version of me that was going to wait until the watch said 50 to go in for a test would have waited a long time. That version of me was also building the wrong story about himself: that he had a modest engine and needed to fight for every adaptation. None of that was true.
This part of the result was, oddly, building. Not because I felt proud of the number. I have done nothing to earn it. What it changed was the frame: the engine is not the limiting factor. It has not been for a long time. Whatever has been holding the running back, it is somewhere else in the system.
Shock two: the chassis
Then came the part of the report that I am still chewing on.
The numbers, side by side:
| km/h | HR (bpm) | Lactate (mmol/l) |
|---|---|---|
| 6 | 138 (LT) | |
| 8 | 158 | 2.7 |
| 10 | 172 | 3.8 |
| 12 | 182 (AT) | 4.5 |
| 14 | 191 | |
| 16 | 199 (max) | 10.2 |
What this says:
- The aerobic threshold (LT) sits at 138 bpm and 6 km/h. The pure aerobic zone, the one fueled mostly by fat, the one where economy is built, tops out at walking pace.
- During the entire test I never worked in that zone. I walked through it because the test started above it.
- The anaerobic threshold (AT) is at 182 bpm and 12 km/h. Above that I am burning glycogen and stacking lactate.
- The lactate curve is flat through the mixed zone, then snaps vertical late and ugly: 4.5 to 10.2 between 12 and 16 km/h. Weak buffering.
- Recovery looked clean on paper (3 minutes), but the lab flagged it as a sign that current training volume and intensity are mismatched. Signs of overreach.
In a sentence: I have a generously-sized engine bolted onto almost no aerobic chassis. Catastrophe.
This is the part that should not have been possible. I have run 3 to 4 times a week, plus two strength sessions, for three years. I have not skipped a week. I have completed structured 5k programs from Garmin at 100% realisation. After reading Daniels and McMillan I was about to start something more sophisticated. By any reasonable definition I have been a consistent, even slightly compulsive, recreational runner.
And the test says: no aerobic base.
How? Because every easy run was pointed at the watch. Every easy run drifted up to 155 bpm because that is where the watch rewards you. For three years I was almost exclusively training in the mixed and anaerobic zones, Zone 3 and 4, and calling it base. The “easy” runs were never easy. The system never got the conditions it needed to build aerobic capacity. The neighbor, who started doing real Zone 2 after his test, has been quietly building the chassis I never had. That is what the shuffling was. That is why he is faster now.
The single most uncomfortable line in the report is the one that flags recovery time as a sign of overreach. My system has been running on a chronic stress signal for years and I had no idea, because the watch said the numbers were fine.
One footnote on the LT number itself. 6 km/h at 138 bpm is shockingly low. In the field, on a normal day, I can hold something like 8 km/h at 135 to 138. That gap is wide enough to ask honest questions about. Maybe the test caught me on a bad day: short sleep, stress before the mask, a coffee too many. Maybe treadmill running pulls heart rate up relative to outdoor running for me. Maybe the strap and the lab gear simply disagree by a few beats. None of that rescues the underlying picture, though. Even if the real-world LT sits closer to 8 km/h, that is still a slow jog, and I have spent three years calling 10 to 11 km/h “easy.” The diagnosis does not move. It just gets one degree less brutal.
A second confirmation
A few months ago, for unrelated reasons, I had run a deep hormonal panel. The picture there was already clear: HPA axis dysregulation. Free testosterone and SHBG suppressed, DHEA-S below range, adrenals tapped. The other axes (thyroid, estradiol, prolactin, morning cortisol) clean. At the time I noted it, looked into it, and could not connect it to anything specific. Recent follow-up bloods echo the same pattern; DHEA-S is climbing slowly but still under range.
After the treadmill test, the connection is obvious. Three years of “easy” running at 155 bpm, four times a week, plus strength, with not a single deload week. The endocrine picture and the lactate curve are the same story told twice. Two symptoms of one process: chronic, low-grade overreach with no rebuilding window.
This is the kind of thing that does not show up in any one data stream cleanly. The watch never flagged it. The blood work flagged it, but in language I could not decode without a frame. The treadmill test made the system’s complaint legible.
What the plan looks like now
The instruction set from the lab is blunt and structured:
- Aerobic, 2 to 3x per week. HR below 138 bpm, 60 to 70 minutes. This is going to feel insulting and slow. That is the point.
- AT intervals, 1x per week. Mostly time below the threshold, short doses at it. Not hero sessions.
- Lactate-tolerance intervals, 1x per week. Work-to-rest ratio matters: rest equal to or shorter than work, so the buffer system is forced to adapt. Hills or stairs make it sharper.
- Strength endurance and power, 1x per week.
- Specialist work, 1x per week. Race-specific pace and conditions.
Eight-week periodization blocks: three weeks of work, one week deload, then the next mesocycle starts each threshold zone about 5 bpm higher. Retest at the end. The watch zones for now:
- Zone 1: 131 and below
- Zone 2: 132 to 138
- Zone 3: 139 to 166
- Zone 4: 167 to 182
- Zone 5: 183 and above
I look at Zone 2 (132 to 138) and immediately want to argue with it. That is exactly the response that produced this problem in the first place.
What I am taking from this
Four things I want to remember.
One. The test I was trying to postpone for ego reasons was the test I needed when I needed it. If I had waited until the watch said 50, I would have spent another six months building the wrong thing on the wrong base. The right time to be measured is before you are “ready,” not after. Confirmation testing is theater. Diagnostic testing is information.
Two. A high VO2max without an aerobic base is not a flex. It is a warning. It means the engine has capacity the rest of the system cannot use, which is exactly why my economy was bad, my lactate spiked, and my curve was ugly. Capacity without economy is horsepower without a transmission. The Garmin number was flattering the wrong thing, and underestimating the real engine by twenty points while doing it.
Three. Three years of “consistency” is not the same as three years of correct stimulus. I was consistent at hammering one zone. The watch was consistent at rewarding it. Multiplying years onto the wrong input does not get you closer to the right output. It gets you a chronic stress signal in your blood and a flat curve on a treadmill, side by side.
Four. When something in your environment stops computing, your slower neighbor suddenly running away from you, that is data. The right response is not to grind harder on what you were already doing. It is to find out what they know that you do not.
The retest is in eight weeks. The goal is not a higher VO2max number. The engine is, frankly, the thing I least need to work on. The goal is a slower lactate curve, a wider mixed zone, thresholds shifted right. A chassis under the engine. And, with any luck, an HPA axis that has remembered what rest looks like.
Not more force. Better structure.