Long run · Thursday, 27 August 2026 · Week 1, Durability Base
Long run, 16 miles
31 weeks to MDS
My write-up for this run isn't up yet. Everything the watch recorded is below.
- Distance
- 16 mi
- 25.7 km
- Moving time
- 3h 46m
- started 17:08
- Average pace
- 14:11
- per mile
- Heart rate
- 123
- average · max 144
- Climb
- 1043 ft
- 318 m
- Conditions
- –
- 88% humidity
An extra run, not on the plan.
Heart rate against my cap
My easy running has a heart rate ceiling of 126 bpm. It keeps the effort aerobic while my legs, tendons and joints catch up with the mileage. A run counts as over the cap when the average is more than 2 beats over it, or more than a fifth of the time sits above it.
Over the cap. Average 123 bpm, with 25% of the run above 126. The fix is to slow down, walk the steeper bits if I need to, and let it settle.
How well the running held up
I compare how efficiently I was running early in the run (speed for each heartbeat, corrected for hills) with the late part. The drop was 7.5%. Over 5% is what I call a late fade. That band is a coaching convention, not a validated threshold.
A sustained drop began around 2h 24m into the run.
Late on, pace slowed 5.9% and heart rate rose 1.8%.
First half against second half
Comparing pace against heart rate in the first half with the second, the gap was 6.2%. Under 5% is the convention I coach to: it suggests the aerobic side coped with the length of the run. It says nothing about why.
Mile by mile
| Mile | Pace | Avg HR | Climb |
|---|---|---|---|
| 1 | 13:12 | 117 | 95 ft |
| 2 | 13:03 | 121 | 13 ft |
| 3 | 15:27 | 120 | 128 ft |
| 4 | 14:22 | 120 | 82 ft |
| 5 | 13:36 | 123 | 52 ft |
| 6 | 13:06 | 124 | 13 ft |
| 7 | 14:52 | 120 | 121 ft |
| 8 | 14:29 | 123 | 46 ft |
| 9 | 13:33 | 123 | 52 ft |
| 10 | 15:13 | 125 | 135 ft |
| 11 | 14:26 | 126 | 82 ft |
| 12 | 14:11 | 123 | 20 ft |
| 13 | 14:13 | 124 | 33 ft |
| 14 | 14:46 | 126 | 79 ft |
| 15 | 14:26 | 125 | 20 ft |
| 0.95 | 14:06 | 127 | 13 ft |
Heart rate in orange is above the 126 bpm cap.
Figures from my watch via Intervals.icu, read by the Ultra Event Training app. Heart rate from a watch is a proxy for effort, not a lab measure. The efficiency figures compare speed per heartbeat early and late in a run with a hill correction; they show what changed, not the cause.