The Fastest Way to Run a Sub-3 Hour Marathon (Start Here) - Lee Grantham

Aug 13, 2025

Intro

This is a quick summary of The Fastest Way to Run a Sub-3 Hour Marathon (Start Here) from Lee Grantham. 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

Speed first: To break 3 hours you must become a faster 5 km and 10 km runner; aim for about 3:45 min/km (≈6 min/mi) pace.
Target paces: 5 km in ~18:45, 10 km in ~37‑38 min. These times translate to a marathon pace of ~4:15 min/km.
Progressive training: Start where you are, keep weekly consistency, and balance hard interval days with easy runs and proper taper.
Heart‑rate monitoring: Use HR during intervals (peak and recovery) to gauge effort and ensure sustainability.
Weekly balance: Avoid over‑reaching; if you’re still recovering on long‑run day, dial back the interval intensity.

Workout Example

Session 1 – 1 km repeats

Warm‑up 10‑15 min easy running.
6 × 1 km at 3:45 min/km with 60 s jog/recovery between reps.
Cool‑down 10 min easy.

Session 2 – 400 m repeats

Warm‑up 10‑15 min.
15 × 400 m at 3:30 min/km (≈15 s faster than target) with 60 s recovery.
Cool‑down 10 min.

Session 3 – 1600 m repeats

Warm‑up 10‑15 min.
3 × 1600 m at 3:45 min/km (or a touch slower if needed) with 60 s recovery.
Cool‑down 10 min.

Progression Run (6 km)

2 km @ 4:10 min/km → 2 km @ 4:00 min/km → 2 km @ 3:50 min/km (or aim for 3:45 min/km on the final 2 km).

Adjust all paces to match your current fitness; the Pacing app makes it easy to swap in your own pace numbers.

Closing Note

Give these sessions a try, track your heart‑rate and how you feel, and gradually tighten the paces. With consistent work you’ll move from a 5 K‑focused runner to a sub‑3‑hour marathoner. Customize the intervals to your own speeds in the Pacing app and enjoy the progress – you’ve got this!