The number every runner should know but doesn't

Huge thank you to Precision Fuel and Hydration for sponsoring this video. Head to their website to fill out the free questionnaire or book a sweat test at one of their labs: https://visit.pfandh.com/lovethegrind Most runners think about sweat as one data point. Drink more, job done. But it's actually two completely separate numbers and getting either one wrong is the reason you cramp up, fade in the heat or worse. I went to Precision Fuel and Hydration HQ in Dorset and did two full threshold sessions in the lab, one in normal conditions and one in a heat chamber cranked to 37 degrees, with lactate testing, sweat rate testing, and sodium concentration testing throughout. Other useful links from Precisions Knowledge Hub: Pre loading your hydration: https://www.precisionhydration.com/pe... How to estimate your sodium loss: https://www.precisionhydration.com/pe... Love the grind 🤍 Shop lululemon now ➡️ https://creatorlink.shop/3OEftaZ (Aff link) Shop all Precision Fuel & Hydration ➡️ https://visit.pfandh.com/PhilyB Shop Nomio ➡️ https://drinknomio.com/en-gb Sign up to the mailing list ➡️ https://philybowden.com/pages/newslet... Head over to my Instagram @philybowden for more daily updates and training insights! WANT TO SUPPORT MY CHANNEL? To support my running career, the channel and creation of these videos - Check out my Patreon that's linked below, with different levels of support on offer and you can gain access to extra exclusive content!   / philybowden   Check out my FREE Training plans: https://philybowden.com/pages/trainin... Phily’s Favourite - Here are a few things I use everyday that I love: *Just to be transparent these are all affiliate links My Watch: https://amzn.to/4bgFHJk My Sunglasses: https://rstyle.me/+-jsYsfkgoJDyZPjPvz... Wundertrain jacket: https://creatorlink.shop/4qNbMgI Scuba jogger: https://creatorlink.shop/4aH4DbH Scuba hoodie: https://creatorlink.shop/46gTlcM Align high rise short: https://creatorlink.shop/4tHHgYh Follow me here: Instagram:   / philybowden   Strava:   / strava   Want to work with me: [email protected] Follow Daniel: Instagram: https://instagram.com/daniel_moves_?i... Need any videos edited?! Daniel (My husband and the editor of my videos) has got you covered! Drop him a line at: [email protected] Instagram: https://www.instagram.com/dangerlimee... Website: https://www.dangerlime.com/ Check out my coaching website: https://www.philybowden.com What's in this video ⬇️ 0:00 – Why sweat matters for runners 0:59 – What We're Testing Today and Why 1:32 – The Missing Piece of My Marathon Prep 3:22 – A Tour of thePrecision Fuel and Hydration HQ 4:38 – Session One: 9 Miles of Threshold in the Lab 6:24 – Lactate Testing Explained 6:57 – Sweat Rate vs Sodium Loss: What's the Difference? 8:14 – Session One Done: The Results 8:35 – Newlyweds Salty Edition: The Sodium Test 9:24 – How the Sodium Test Actually Works 9:49 – My Sodium Results: What They Mean 11:40 – What to Do With Your Number on Race Day 13:34 – How to Test Your Sweat Rate at Home 14:36 – Session Two: The Heat Chamber 15:51 – Running at 37 Degrees: What Happened 17:10 – Why You Must Adjust Pace in the Heat 19:23 – Comparing AM and PM Sweat Rates 21:31 – Pulling It All Together: My Numbers 22:54 – What I'm Most Excited About Next 23:33 – How to Get Your Own Data #hydration #sweattest #marathontraining #philybowden #precisionfuelandhydration #runningscience #electrolytes #heattraining #marathonfueling #runningperformance