Run · Monday, 24 August 2026 · Week 1, Durability Base
Run, 8.1 miles
31 weeks to MDS
My write-up for this run isn't up yet. Everything the watch recorded is below.
- Distance
- 8.1 mi
- 13 km
- Moving time
- 1h 44m
- started 19:46
- Average pace
- 12:49
- per mile
- Heart rate
- 123
- average · max 147
- Climb
- 643 ft
- 196 m
- Conditions
- –
- 61% humidity
The planned easy 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 123 bpm, with 22% 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 -0.2%. Under 5% is what I call held. That band is a coaching convention, not a validated threshold.
Late on, pace quickened 3.2% and heart rate rose 3%.
Confidence: low (the final third contained substantially more climbing; the hill correction changed this reading by about 11 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 2.6%. 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 | 11:56 | 120 | 92 ft |
| 2 | 13:12 | 126 | 128 ft |
| 3 | 12:58 | 122 | 39 ft |
| 4 | 12:32 | 122 | 59 ft |
| 5 | 13:59 | 122 | 115 ft |
| 6 | 12:20 | 120 | 0 ft |
| 7 | 13:18 | 126 | 128 ft |
| 8 | 12:41 | 126 | 82 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.