Tread Lightly Running Science Podcast

You likely have heard both sides of the debate, as one side argues that sodium supplementation is overrated, while the other side shills sports drinks with a full gram of sodium. In this episode, we dive into the research to present you with a nuanced, science-backed discussion on the widely varying sodium needs of runners. You will learn how to determine your sweat rate and sodium needs, if sodium will prevent muscle cramps, and more.

Thank you to our sponsors:
✨ Tailwind: Complete sport nutrition made simple, including hydration mixes, high-carb sport drinks, endurance fuel, and recovery mixes. Use code TREADLIGHTLY20 at https://tailwindnutrition.com/TREADLIGHTLY for 20% off your first purchase.

In this episode, you’ll learn:
✅ Sweat rate vs sweat concentration
✅ The role that sodium plays in hydration, carbohydrate absorption, and more
✅ If sodium supplementation prevents muscle cramps
✅ How to know if sweat testing is appropriate or not
✅ The signs and symptoms of too much and too little sodium
✅ If sodium pre-loading works before a race
✅ Ideal sources for sodium supplementation during runs
✅ Why too low sodium can be dangerous
Tread Lightly Running is hosted and researched by Amanda Brooks and Laura Norris, MSc. Production, show notes, and graphics by Laura Norris.

References
🔬PMID: 42190283
🔬PMID: 40089940
🔬PMID: 41561158
🔬 https://link.springer.com/article/10.1186/s44410-025-00011-9
🔬 PMID: 36431252

If you enjoyed this episode, you may like:
🎧 What Your Running Gel Label Actually Means with Kylee Van Horn (8 Aug 2025)
🎧 The Science of the Long Run (17 July 2026)

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/

The long run is a staple of training plans from the 5K to ultra - but why? In this episode, we discuss the science of long runs, including the physiological adaptations, progressions, specificity and more. Plus, we answer your questions about why sleep is difficult after a long run, if walk breaks are okay, and if you treadmill long runs at a lower heart rate are better than outdoors.

Thank you to our sponsors:
✨ Mizuno: Shop Mizuno’s newest bouncy supertrainer: https://runtothefinish.com/neovista3/

In this episode, you’ll learn:
✅ Why long runs are beneficial
✅ If fueling your long runs compromises adaptations
✅ How to progress your long runs
✅ How often you should do long runs at goal race pace
✅ Cardiac drift, cadence, and other things to pay attention to on long runs
✅ Terrain specificity during long runs
If you enjoyed this episode, you may like:
🎧 Gut Training for Runners with Claire Shorenstein, CSSD, MS (10 July 2026)
🎧 Base Building Blueprint to Set Yourself Up for a Year of Running Success (2 Jan 2026)
🎧 Half Marathon Taper: It’s Not Just Less Running (27 March 2026)

References
🔬PMID: 38389144
🔬PMID: 36173597
🔬PMID: 40878015
🔬 PMID: 40623829
Tread Lightly Running is hosted and researched by Amanda Brooks and Laura Norris, MSc. Production, show notes, 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/

Most runners have experienced sloshy stomach, nausea, urgency, or other GI issues during a race or run. However, GI problems do not have to be a part of running! We discuss gut training with board-certified sports dietitian Claire Shorenstein. You will learn protocols for gut training, if gut training reverses during your taper, and how to pick the fuel that sits best with you.

Thank you to our sponsors:
✨ Tailwind: Complete sport nutrition made simple, including hydration mixes, high-carb sport drinks, endurance fuel, and recovery mixes. Use code TREADLIGHTLY20 at https://tailwindnutrition.com/TREADLIGHTLY for 20% off your first purchase.

In this episode, you’ll learn:
✅ What gut training actually is
✅ An effective gut-training protocol for runners
✅ How your daily diet impacts gut training
✅ Understanding carbohydrate sources and gut transports
✅ How chewing is part of gut training
✅ If gut training detrains during a taper or off-season
✅ How to improve gut tolerance when racing in the heat
✅ If you need to train your gut for hydration

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

Connect with our guest:
Claire Shorenstein, MS, CSSD is a board-certified sports dietitian. She is an accomplished ultra-marathoner and Boston Marathon finisher as well as certified running coach. She works 1:1 with endurance runners to help them achieve their nutrition and performance goals.
You can connect with Claire:
🌐 https://www.eatforendurance.com/
📲 https://www.instagram.com/eatforendurance/
🎙️Eat for Endurance Podcast

If you enjoyed this episode, you may like:
🎧 What You Really Need to Know About Fueling Your Runs (28 Nov 2025)
🎧 A Science-Backed Guide to Hydration for Runners (15 Nov 2024)
🎧 What to Eat Before a Race, from the 5K to Marathon (24 April 2026)

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/

Are you noticing that you are tired all the time and cannot seem to hit your paces in training? Those are not symptoms to ignore. Sometimes, these are signs of low ferritin levels that warrant bloodwork and a doctor visit. In this episode, we examine the research on low ferritin and running, including the causes, how to treat, and how to prevent low ferritin.

Thank you to our sponsors:
✨ Mizuno: Shop Mizuno’s newest bouncy supertrainer: https://runtothefinish.com/neovista3/

In this episode, you’ll learn:
✅ Why general population reference ranges for iron are not appropriate for endurance athletes
✅ Why iron and ferritin levels matter so much for runners
✅ Signs and symptoms of low ferritin levels in runners
✅ Why runners are so prone to low ferritin levels
✅ How long it takes for iron levels to increase
✅ What impacts your iron intake and absorption

References
🔬PMID: 35565873
🔬PMID: 38407751
🔬PMID: 31413088
🔬 https://lpi.oregonstate.edu/mic/minerals/iron#toc-nutrient-interactions
🔬 PMID: 36728680
🔬PMID: 25247929
🔬https://link.springer.com/article/10.1007/s40279-024-01992-8
🔬\https://cdnsciencepub.com/doi/abs/10.1139/apnm-2012-0361#.WYClN9PyvBJ
🔬 PMID: 28452395
🔬 PMID: 37895389
🔬 https://ashpublications.org/blood/article/140/Supplement 1/11074/488529/Prevalence-of-Iron-Deficiency-in-Endurance-Runners

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

Repeatedly missing your running goals is a frustrating experience, especially if you are training hard for a race. In this episode, we discuss what causes a half marathon plateau and solutions to break through to the next performance level. You will learn how to know if you need more speed, goal pace training, endurance, or strength when training for a half marathon. Even if your races have not plateaued, the advice in this episode will help you keep progressing in your half marathon times.

Thank you to our sponsors:
✨Title Nine: Comfortable sports bras that actually fit, from a women-owned company. Use code RUNTOTHEFINISH for free shipping at https://runtothefinish.com/title-nine/
✨ Tailwind: Complete sport nutrition made simple, including hydration mixes, high-carb sport drinks, endurance fuel, and recovery mixes. Use code TREADLIGHTLY20 at https://tailwindnutrition.com/TREADLIGHTLY for 20% off your first purchase.

In this episode, you’ll learn about:
✅ What defines and causes a performance plateau
✅ Recovery variables that could cause a plateau
✅ Why more is not always the solution to a performance plateau
✅ If speed, endurance, or another variable is your limitation
✅ Why overdoing half marathon pace could plateau you

If You Enjoyed this Episode, You May Like:
🎧 Does Zone 2 Actually Matter for Runners? (6 June 2025)
🎧 VO2Max Workouts, Threshold Runs, and More: Understanding the Different Type of Running Workouts (12 April 2024)
🎧 Why 80/20 Does Not Work for Every Runner with Jonah Rosner (12 December 2025)
🎧 Fatigue Resistance: How to Not Slow Down at the End of Your Race (18 April 2025)

References
🔬PMID: 32421886
🔬PMID: 41765005
🔬PMID: 40740427

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