Long run · Sunday, 27 September 2026 · Week 5, Durability Base
Long run, 12.1 miles
26 weeks to MDS
My write-up for this run isn't up yet. Everything the watch recorded is below.
- Distance
- 12.1 mi
- 19.4 km
- Moving time
- 2h 41m
- started 15:11
- Average pace
- 13:22
- per mile
- Heart rate
- 127
- average · max 147
- Climb
- 817 ft
- 249 m
- Conditions
- 19°C
- 72% humidity · wind 23 km/h
The planned long run, a different distance from 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 127 bpm, with 54% 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 3.3%. Under 5% is what I call held. That band is a coaching convention, not a validated threshold.
A sustained drop began around 2h 09m into the run.
Late on, pace slowed 2.8% and heart rate rose 0.6%.
Confidence: medium (the hill correction changed this reading by about 7 points, and it is an estimate).
First half against second half
Comparing pace against heart rate in the first half with the second, the gap was 2.2%. 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 | 12:32 | 128 | 95 ft |
| 2 | 12:58 | 125 | 20 ft |
| 3 | 14:38 | 130 | 128 ft |
| 4 | 14:07 | 128 | 89 ft |
| 5 | 13:10 | 124 | 39 ft |
| 6 | 12:26 | 124 | 7 ft |
| 7 | 14:03 | 122 | 135 ft |
| 8 | 13:22 | 128 | 39 ft |
| 9 | 13:19 | 126 | 66 ft |
| 10 | 13:49 | 130 | 95 ft |
| 11 | 12:48 | 127 | 7 ft |
| 12 | 13:35 | 129 | 59 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.