Cover art for podcast The Human Upgrade with Dave Asprey—formerly Bulletproof Radio

The Human Upgrade with Dave Asprey—formerly Bulletproof Radio

937 EpisodesProduced by Dave AspreyWebsite

For a decade, Dave Asprey, “the father of biohacking,” elevated what you knew about the capabilities of your mind and body across a thousand episodes of Bulletproof Radio. Now, he’s evolving it even further in his plan to upgrade humanity. You’re invited to expand your knowledge, explore your own pe… read more


Shorten Your Cardio Time Even More with REHIT – Ulrich Dempfle with Dave Asprey : 834

Cardio sometimes gets a bad rap; people either do too much or too little.  

You’ve likely heard of HIIT (High Intensity Interval Training). In this episode of Bulletproof Radio, you’ll learn about the benefits of REHIT (Reduced Exertion High Intensity Interval Training) to improve cardiovascular fitness. 

Ulrich Dempfle, co-founder of CAROL, joins me on the show to talk about REHIT and the science behind how you can get fit in less than 9 minutes. Yes, really.

The CAROL bike is founded on REHIT principles and gets right to the sweet spot for your health and fitness with added AI programming. 

Decades of progressive research going back to the 1970s looked at high intensity training. New studies specifically show that by riding a CAROL bike you can:

-improve your fitness by 12 percent in 8 weeks, measured by V02max. This adds two years of healthy lifespan!

-lower your risk of Type II Diabetes by 60% in 8 weeks

-burn twice as many calories minute-per-minute compared to traditional exercise. And keep burning calories for several hours after your ride.

“Anything that's longer than 20 seconds and anything that's longer than two times of 20 seconds is not maximum intensity because you couldn't do maximum intensity for these sustained periods,” Ulrich says. “So, your slope and the change in intensity is just much lower on these traditional forms of HIIT.”

The idea for the stationary CAROL bike came alive in 2012 during work on chronic disease management programs for people with diabetes. Not surprisingly, researchers found it challenging to get people to exercise. The main excuse for most people was lack of time and frustration about slow results.

CAROL solves that. The bike’s core ride lasts 8 minutes and 40 seconds. It’s a gentle-paced ride with two 20-second sprints. On the sprints, you go all out as hard as you can. 

But this isn’t just a conversation about riding a bike. We cover the science of how rapid glycogen depletion triggers the release and activation of certain signaling molecules (AMPk and PGC-1a), which triggers mitochondrial biogenesis. And why maximum intensity sprints ‘saturate’ the signaling response mechanism.

“When you do those sprints, you increase the energy demand in your body very suddenly, about 100 times higher compared to rest,” Ulrich says.” With this spike in energy demand, the muscle just cannot use its usual source of fuel, which is either fat or sugar that it takes from the bloodstream”. 

“Instead, it would have to burn what's called muscular glycogen, so that is a storage form of sugar that is stored in the muscle itself. That's the emergency reserve. With the exercise, we force the muscle to tap into those energy reserves, and that kicks off a cascade of molecular changes, of triggers, where certain signaling molecules are released that basically tell the body to get fitter and stronger.”

Enjoy! And get more resources at Dave.Asprey/podcasts.

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