In this episode of the Primal Shift Podcast, I sit down with CAROL Bike CEO Ulrich Dempfle to discuss the science and benefits behind Reduced Exertion High-Intensity Interval Training (REHIT), a fitness modality developed to provide the most effective workout in the shortest possible amount of time.  For example, the CAROL Bike gives you a full cardio workout in just eight minutes, focusing on two strategically-timed 20-second sprints. Dempfle explains how this is possible, detailing the science behind how REHIT induces glycogen mobilization and the release of key molecules that signal the body to build more mitochondria, thereby increasing aerobic capacity and overall fitness. We also talk about Dempfle’s journey from working in the German automotive industry to healthcare, where he recognized the critical role of exercise in the prevention of injury and disease, as well as the challenge of getting people to commit to regular workouts. Whether or not you decide to give CAROL a try, this episode provides a valuable introduction to the science and application of REHIT, with tips on how to leverage this ultra-efficient training strategy to optimize your health and wellness. In this episode: 00:00 - Intro 02:16 - Benefits of Short, Intense Workouts 04:18 - The Difference Between REHIT and HIIT 07:24 - Ulrich Dempfle’s Background and Journey 09:05 - Addressing Time Constraints In Exercise 12:00 - The CAROL Bike’s Effect on Your Body 17:52 - Psychological Aspects of Intense Workouts 23:50 - Optimal Frequency for REHIT Workouts 26:20 - Combining CAROL with Other Fitness Routines 30:00 - Additional Benefits and Metabolic Health 35:30 - Comparison With Other Exercise Equipment  39:40 - Addressing Advanced Biohacking Techniques  44:10 - Summary of Key Points and Benefits  47:00 - Final Thoughts and Wrap-up Don't forget to subscribe for more insightful conversations with experts in health, fitness, and beyond.  #PrimalShiftPodcast #UlrichDempfle #REHITWorkout #CAROLBike   Learn more: I’ve been a big fan of the CAROL Bike for a number of years, and explain how I use it in this review. You can also see me in action on the bike in this video review. I also recorded a video in which I compare CAROL with traditional spinning and air bikes such as the Peloton, Assault and Rogue Echo. Plus, be sure to watch this video of me and my friend competing against each other on CAROL Bike. Thank you to this episode’s sponsor, OneSkin!  OneSkin’s lineup of topical skin health products leverage the power of the company’s proprietary OS-01 peptide to remove dead skin cells, improve collagen production, increase skin hydration and more. Check out my before and after photos in my OneSkin review and visit OneSkin here. About Ulrich Dempfle: Dempfle is the CEO and co-founder of CAROL Bike. After graduating in mechanical engineering from Germany’s leading tech university, he worked with some of Europe’s top automobile manufacturers. From there he moved to London, where he pioneered the use of AI for operational efficiency within UK health services. After watching a BBC documentary on Reduced Exertion HIIT (REHIT), Ulrich realized its potential to be the most effective cardio workout. The problem? REHIT was only possible in a lab setting. So Ulrich co-founded CAROL and worked with the world’s leading exercise researchers to take REHIT out of the lab. 40 prototypes later, the world’s only REHIT exercise bike was launched. Email: ulrich.dempfle@carolbike.com Website: https://carolbike.com/ Twitter Link: https://twitter.com/thecarolbike Instagram Link: https://www.instagram.com/thecarolbike/ Facebook Link: https://www.facebook.com/thecarolbike Youtube Link: https://www.facebook.com/thecarolbike   More From Michael Kummer: Website: https://michaelkummer.com YouTube: https://youtube.com/@MichaelKummer Instagram: https://instagram.com/mkummer82 Facebook: https://www.facebook.com/realmichaelkummer