Ironman Training Diary - May 18, 2026

Saturday morning one of our children had an early soccer game so I was unable to attend the usual group run. This was probably a good thing because following the advice of Apollo, I wanted to substantially reduce my average running pace and that wouldn’t have happened with the group. However, I wound up beating myself up anyway because at the beginning of the 9am game my occasional training partner, nemesis, and fellow soccer Dad Charlie challenged me to a pushup contest. Over the course of the two morning games I wound up doing 370 pushups. That sounds like a lot until I tell you Charlie wound up doing 625. Damn you Charlie <shakes fist>!!!

After the games we returned home and I inhaled three large pieces of Costco pizza, put on my new Polar HR chest strap, and headed out for the scheduled 80 minute run. Actually, that’s simplifying things a bit; I went around in circles for 20 minutes trying to figure out how to sync the strap to the horrible Polar Flow app. I just don’t understand why these companies put so much effort into building great hardware and then are like fuck it when it comes to the software.

I bought the Polar because a friend of mine mentioned the Garmin might be inaccurately recording HR, something that was coincidentally mentioned in the distance training book I’m reading. So I figured I’d wear both and see how closely they corresponded. Comically as soon as I started the run activity on my Garmin it asked me if I wanted to connect to the chest monitor. In my angst to get going (weather wasn’t great Saturday), I pressed yes and now I don’t know whether the Garmin just let the Polar take over HR measurement activities lol. The apps are in fact showing two different numbers (Polar Flow shows 159bpm HR avg whereas the Garmin shows 161bpm), but if they did indeed measure independently then why did my Garmin ask me to connect the Polar?

Sooner or later somebody is going to tell me the Polar HR is inaccurately tracking something or other, then I’ll have to buy another device and strap it on somewhere. My neck maybe?

Something that catches my eye regarding the below May 9 vs May 16 run comparisons is the -7 average HR variation. I was running a lot harder throughout the May 9 run, however we did walk for 9 minutes which undoubtedly skewed the numbers. Furthermore, did the three giant pieces of Costco pizza result in a higher average HR? I need to look this up.

Anyway, on to the numbers…

Here is Apollo’s run analysis:

🤖 Apollo (AI) analysis

Mile splits

Mile	Pace
1	13:18
2	12:30
3	12:45
4	12:14
5	12:34
6	13:43

HR drift profile

Quarter	Avg HR
0–20 min	149
20–40 min	163
40–60 min	166
60–80 min	162
First 10 min	141
Last 10 min	158

Compare to May 9 — same distance

	May 9	May 16	Δ
Distance	6.01 mi	6.09 mi	~same
Duration	63 min	80 min	+17 min
Avg pace	10:32/mi	13:09/mi	−2:37
Avg HR	168	161	−7 bpm
Z5 time	23 min	0 min	−23 min
Walk breaks	9:13	0	none

Same distance, lower HR, no walking, deliberately slower. This is exactly the protocol I was hoping you’d commit to. You ran 27% longer in duration and your heart still worked less hard. That’s aerobic base economy showing the first real signs of building.

Add to that:

Pacing discipline: miles 1–5 in a tight band (12:14–13:18). You held the slow pace through the middle of the run instead of letting it creep up.
HR drift is shrinking the right way. Yes, you still drifted from 141 → 158 over the hour (+17 bpm). But on May 9 you drifted from ~150 to over 180 and had to walk. Tonight you absorbed an 80-minute aerobic load without breaking.

Things worth watching

Cadence dropped to 149 spm (vs. your usual 158–159). At slower paces some cadence drop is normal, but 149 is on the low side — risk of overstriding and tendon stress. Try mentally cueing “quicker, lighter steps” without speeding up. Aim for 155+ even at this slow pace.
Max HR 173. That’s actually 3 bpm above the age-estimated HRmax (170) your zones are calibrated against — meaning your true HRmax is probably 175–180, which would push all your zone boundaries up. Bottom line: the 81% “Z4” time is partly an artifact of conservative zone estimates. Your work tonight was likely closer to high Z3 / low Z4 by accurate zones — still not pure Z2 base, but better than the raw number suggests.
VO2 max still 39.0. Don’t expect movement yet — this protocol takes 3–4 weeks before the number shifts. You’ve been at it for one. Patience.

The big picture

Tonight you ran the kind of workout that builds Ironman engines. 80 minutes of sustained aerobic effort, no breaks, no ego pace, controlled HR. Stack 8–10 more of these over the next month and your VO2 max will move. Two long runs of this shape per week (Sat + Sun, or split) is the staple endurance athletes build their seasons on.

This is the version of “easy” the textbook means. Keep doing this.

I just wanted to note that on the May 9 run I didn’t actually have to walk; my running partner that day needed a break so I walked too. Even so, point taken.

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