What is Zone 3 Really Doing to Your Running Fitness? [Remastered]

Will running in the “grey zone” cause you to flounder - or appropriately dosed amounts let your fitness flourish? This remastered episode, originally from January 2024, provides a nuanced discussion on how moderate intensity running can be beneficial in the correct doses - but why you don’t want to train every day in this zone.

✨Join us on Patreon.com/treadlightlyrunning or subscribe on Apple Podcasts starting in December, when we’ll be releasing special subscriber-only content!

In this episode, you’ll learn:

✅ What is the grey zone in running?

✅ The benefits and detriments of running in the grey zone

✅ How to use the talk test

✅ When to use zone 3 training

✅ Should you do all of your long runs at marathon pace?

✅ What is polarized training (hard days hard, easy days easy)

✅ Marathon pace/zone 3 workouts

✅ Zone 2 vs zone running when you are a beginner runner

If you enjoyed this episode, you may also like

🎧 Why 80/20 Doesn’t Work For Every Runner (12 Dec 2025)

🎧 Why You Need All Training Zones to Improve a a Runner (29 Aug 2025)

🎧 Does Zone 2 Actually Matter for Runners? (6 June 2025)

References:

🔬 PMID: 33344993

🔬 PMID: 36900796

🔬PMID: 35661059

🔬PMID: 26578968

🔬Skiba, Scientific Training For Endurance Athletes

⁠https://www.frontiersin.org/articles/10.3389/fspor.2019.00070/full⁠

Tread Lightly Running is hosted and researched by Amanda Brooks and Laura Norris, MSc. Production and graphics by Laura Norris.

Let’s stay connected:

➡️ Tread Lightly Running Podcast on Instagram: https://www.instagram.com/treadlightlyrunning/

➡️ Laura Norris Running on Instagram: https://www.instagram.com/lauranorrisrunning/

➡️ Subscribe for weekly evidence-based newsletters, straight to your inbox, on https://lauranorrisrunning.substack.com/

➡️ Run to the Finish on Instagram: https://www.instagram.com/runtothefinish/?hl=en

➡️ Thousands of running gear reviews and training guides: https://runtothefinish.com/