Long run · Sunday, 11 October 2026 · Week 7, Durability Base
Sixteen miles hold together despite a late fade on paper
24 weeks to MDS
Sixteen miles in humid conditions, the long run for week seven done exactly as planned. The pace quickened over the distance, 13:18 early to 12:48 late, heart rate rising from 121 to 127 across the same stretch. Eight per cent of the run sat above the cap, but the average landed six under it.
I tagged the run as faded late, and it felt that way by the end, but the watch tells a steadier story. Comparing how efficient the running was early versus late, speed per heartbeat dropped by 1.8 per cent, well inside the band I call held, and pace against heart rate barely drifted between the two halves. One long run like this is not much to go on. I will watch whether the gap between how it felt and what the watch shows closes as the weeks add up.
From my training journal
Easy effort · Faded late
- Distance
- 16 mi
- 25.8 km
- Moving time
- 3h 40m
- started 07:18
- Average pace
- 13:42
- per mile
- Heart rate
- 125
- average · max 153
- Climb
- 1037 ft
- 316 m
- Conditions
- 8°C
- 90% humidity · wind 7 km/h
Planned long run, full distance.
Heart rate against my cap
My easy running has a heart rate ceiling of 131 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.
Under the cap. Average 125 bpm, with 8% of the run above 131.
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 1.8%. Under 5% is what I call held. That band is a coaching convention, not a validated threshold.
Late on, pace quickened 0% 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 0.3%. 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 | 13:18 | 121 | 108 ft |
| 2 | 13:28 | 121 | 26 ft |
| 3 | 14:53 | 126 | 82 ft |
| 4 | 14:24 | 125 | 89 ft |
| 5 | 13:57 | 127 | 85 ft |
| 6 | 12:56 | 122 | 13 ft |
| 7 | 13:57 | 123 | 112 ft |
| 8 | 13:45 | 121 | 72 ft |
| 9 | 12:57 | 126 | 33 ft |
| 10 | 14:41 | 126 | 135 ft |
| 11 | 14:26 | 121 | 85 ft |
| 12 | 13:11 | 128 | 23 ft |
| 13 | 13:37 | 127 | 59 ft |
| 14 | 13:53 | 125 | 66 ft |
| 15 | 13:23 | 129 | 33 ft |
| 16 | 12:48 | 127 | 7 ft |
Heart rate in orange is above the 131 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.