Jonah Rosner is an applied sport scientist who spent 10 years working with athletes and teams from all major American professional team sports, particularly the National Football League.

He's a certified running coach and strength and conditioning specialist and he previously partnered with Nike to run the Nike Running Performance Lab in New York City. You can sign up for his Marathon Science newsletter here.

Jonah was also the sport scientist on hand during a fitness retreat I attended last year where I had my VO2 Max measured. Jonah administered the test, which you can watch on Strength Running's YouTube channel.

In this conversation, we myth-bust around the hottest topics in running:

Heat training
How to develop better running economy
Heart rate Zones
Why beginners shouldn't worry about Zone 2
Overpronation
Electrolytes and sodium consumption

If you like this episode, be sure to listen to Facts vs. Fads: Dr. Nick Tiller on Nasal Strips, Organics, Cupping, Detox Diets, & More.

Thank you Previnex!

After resisting most supplements for the better part of my life, I'm cautiously changing my tune. I'm now a Masters runner and in my personal life, I'm optimizing for longevity. I want to be my healthiest self for as long as possible and I'm excited to partner with Previnex to make that happen.

Previnex uses the most bioavailable, clinically tested ingredients, the optimal form and dose of each ingredient, pharmaceutical grade manufacturing, testing of raw ingredients and finished products. For every purchase you make, they also donate vitamins to kids in need.

Their new Muscle Health Plus is something I'm now taking. Turning 40 – and having a thin frame – has made me realize that I need to prioritize lean muscle mass to stay healthy and age well. Muscle Health Plus has creatine, essential and branched chain amino acids, and it's designed in a way to maximize protein synthesis and the absorption of amino acids.

Muscle Health Plus will help you prevent muscle damage, which is particularly important for aging runners who want to protect themselves from muscle loss and recover faster after hard workouts. As is true for all of their products, Previnex adheres to the highest of standards: their ingredients are clinically proven to do what they say they're going to do.

They're now offering international shipping so if you live in the UK, Canada, Australia, or anywhere around the world, you can try Previnex as well.

Previnex offers a 30-day money back guarantee. If you don't feel the benefits of their product, you get your money back no questions asked. With their focus on quality and customer satisfaction, I hope you'll try it!

Use code jason15 for 15% off your first order at Previnex!

Thank you LMNT!

A big thanks to LMNT for their support of this episode! They make electrolyte drinks for athletes and low-carb folks with no sugar, artificial ingredients, or colors. They are offering a free gift with your purchase at LMNT. And this does NOT have to be your first purchase. You'll get a sample pack with every flavor so you can try them all before deciding what you like best.

And BIG news! Their newest flavor is now permanently available : LEMONADE SALT!

LMNT's products have some of the highest sodium concentrations that you can find. Anybody who runs a lot knows that sodium, as well as other electrolytes like magnesium and potassium, are essential to our performance and how we feel throughout the day.

If you're not familiar, LMNT is my favorite way to hydrate. They make electrolytes for athletes and low-carb folks with no Sugar, artificial ingredients, or colors. I'm now in the habit of giving away boxes of LMNT at group runs around Denver and Boulder and everyone loves this stuff.

Boost your performance and your recovery with LMNT. They're the exclusive hydration partner to Team USA Weightlifting and quite a few professional baseball, hockey, and basketball teams are on regular subscriptions. So check out LMNT to get a free sampler pack and get your hydration optimized for the upcoming season.

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