Durabilityby Darren Ware
← The training log

Run · Saturday, 26 September 2026 · Week 5, Durability Base

Run, 5 miles

26 weeks to MDS

My write-up for this run isn't up yet. Everything the watch recorded is below.

Distance
5 mi
8.1 km
Moving time
1h 04m
started 10:59
Average pace
12:46
per mile
Heart rate
128
average · max 149
Climb
315 ft
96 m
Conditions
15°C
75% humidity · wind 13 km/h

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.

39% at or under 12661% above

Over the cap. Average 128 bpm, with 61% of the run above 126. The fix is to slow down, walk the steeper bits if I need to, and let it settle.

Mile by mile

MilePaceAvg HRClimb
112:41124121 ft
212:2212820 ft
313:49131121 ft
412:3613146 ft
512:3512713 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.