Durabilityby Darren Ware
← The training log

Run · Monday, 31 August 2026 · Week 2, Durability Base

Run, 5 miles

30 weeks to MDS

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

From my training journal

“Hurt my lower left back at the weeks and now taking some days off”

Hard effort

Distance
5 mi
8.1 km
Moving time
1h 08m
started 07:19
Average pace
13:33
per mile
Heart rate
122
average · max 140
Climb
315 ft
96 m
Conditions
13°C
93% humidity · wind 12 km/h

The planned run, done as planned.

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.

80% at or under 12620% above

Over the cap. Average 122 bpm, with 20% 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
113:58121121 ft
212:4612020 ft
314:35124112 ft
413:2512346 ft
513:1712213 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.