My Most Punishing Workout in Years – Half Marathon Training at 39 Years Old - Seth James DeMoor

Aug 13, 2025

Intro: This is a quick summary of My Most Punishing Workout in Years – Half Marathon Training at 39 Years Old from Seth James DeMoor. It’s a great watch — we’re breaking it down so you can try the workout today. Be sure to check out the full video for all the details.

Key Points:

The session is a classic track/oval interval: 10 × 1‑mile repeats with 2 minutes of easy jog or walk between each mile.
All miles are run at goal race pace – 5 min per mile (≈ 4:57 / km), the pace he targets for his upcoming half‑marathon.
The workout is done at 5,280 ft altitude in Colorado, adding extra cardiovascular stress.
Mental tips: start confident, stay disciplined on the pace, use the 2‑minute break for quick hydration and a mental reset, and accept the inevitable fade‑off in the later repeats.

Workout Example:

Warm‑up: 10‑15 min easy jog + a few strides

Main set (track/oval):
10 rounds of:
  • 1 mile @ 5 min/mi (≈ 4:57 / km) – aim to hold the pace as long as possible
  • 2 min easy jog or walk (recover, sip water, reset mentally)

Cool‑down: 5‑10 min easy jog + stretch

If you’re using the Pacing app, simply set the interval distance to 1 mile and the target pace to 5 min, then let the 2‑minute recovery timer handle the rest.

Closing Note: Give this tough but rewarding 10‑mile repeat session a go, tweak the pace to match your own race goal, and track the effort in the Pacing app. You’ll boost your half‑marathon speed and mental grit—so lace up and own the track! 🚀