<p>You’ve probably heard of HIIT—but have you heard of “REHIT?”  This isn’t just another workout trend...it’s a new science-backed way to train with <strong>maximum efficiency and zero wasted time</strong>. If you’re still jogging, you’re wasting hours for minimal results. </p><p>In this episode of <em>The Human Upgrade</em>, Dave Asprey sits down with <strong>Ulrich Dempfle</strong>, German-trained engineer and co-founder of <strong>CAROL Bike</strong>, to dismantle outdated cardio advice and introduce the 5-minute protocol that’s obliterating fitness myths. </p><p><br></p><p>Forget the treadmill grind. <strong>REHIT (Reduced Exertion High-Intensity Training) exercising</strong> delivers: </p><p>• 12% VO₂ max increase </p><p>• 6x the fitness gains of daily jogging </p><p>• 62% drop in diabetes risk </p><p>• 5x more BDNF for brain power </p><p>—all with just 8 minutes of effort per week. </p><p><br></p><p>But what is it? Ulrich unpacks the hard data, crushes the Zone 2 obsession, and shows exactly how a brand-new way of exercising is giving explosive results—no matter your age or fitness level. </p><p><br></p><p><strong>What You’ll Learn in This Episode:</strong> </p><p>• Why Zone 2 cardio is outdated advice for most people </p><p>• The science of REHIT and how 2 sprints beat 2-hour workouts </p><p>• The shocking data on VO₂ max, insulin sensitivity, and lifespan </p><p>• How CAROL uses AI to personalize exercise for <em>any</em> age or ability </p><p>• Why most people fail at fitness—and how to fix it </p><p>• The real role of lactate, BDNF, and HRV in recovery and resilience </p><p>• How perimenopausal women benefit more from REHIT than HIIT or jogging </p><p>• Why adherence—not intensity—is the #1 predictor of results </p><p>• What to do when you’re traveling or don’t have access to the tech </p><p><br></p><p><strong>Resources:</strong>  </p><p>• <strong>Dave Asprey’s New Book - <em>Heavily Meditated</em>:</strong> <a href="https://daveasprey.com/heavily-meditated/" rel="noopener noreferrer" target="_blank">https://daveasprey.com/heavily-meditated/</a> </p><p>• <strong>CAROL Bike Website and use code ‘DAVE’ for a discount –  </strong><a href="https://carolbike.com/" rel="noopener noreferrer" target="_blank">https://carolbike.com/</a> </p><p>• <strong>CAROL Bike Instagram - </strong><a href="https://www.instagram.com/thecarolbike/?hl=en" rel="noopener noreferrer" target="_blank">https://www.instagram.com/thecarolbike/?hl=en</a> </p><p>• <strong>2025 Biohacking Conference</strong>: <a href="https://biohackingconference.com/2025" rel="noopener noreferrer" target="_blank">https://biohackingconference.com/2025</a> </p><p>• <strong>Danger Coffee</strong>: <a href="https://dangercoffee.com/" rel="noopener noreferrer" target="_blank">https://dangercoffee.com</a> </p><p>• <strong>Dave Asprey’s Website</strong>: <a href="https://daveasprey.com/" rel="noopener noreferrer" target="_blank">https://daveasprey.com</a> </p><p>• <strong>Dave Asprey’s Linktree</strong>: <a href="https://linktr.ee/daveasprey" rel="noopener noreferrer" target="_blank">https://linktr.ee/daveasprey</a> </p><p>• <strong>Upgrade Collective – Join The Human Upgrade Podcast Live</strong>: <a href="https://www.ourupgradecollective.com/" rel="noopener noreferrer" target="_blank">https://www.ourupgradecollective.com</a> </p><p>• <strong>Own an Upgrade Labs</strong>: <a href="https://ownanupgradelabs.com/" rel="noopener noreferrer" target="_blank">https://ownanupgradelabs.com</a> </p><p>• <strong>Upgrade Labs</strong>: <a href="https://upgradelabs.com/" rel="noopener noreferrer" target="_blank">https://upgradelabs.com</a> </p><p>• <strong>40 Years of Zen – Neurofeedback Training for Advanced Cognitive Enhancement</strong>: <a href="https://40yearsofzen.com/" rel="noopener noreferrer" target="_blank">https://40yearsofzen.com</a> </p><p><br></p><p><strong>Timestamps:</strong> </p><p>• <strong>00:00</strong> Introduction to REHIT Training </p><p>• <strong>00:24</strong> Meet Ulrich Dempfle: The Mind Behind CAROL Bike </p><p>• <strong>00:51</strong> The Science and Benefits of REHIT </p><p>• <strong>01:44</strong> Comparing Traditional Cardio to REHIT </p><p>• <strong>02:32</strong> Dave Asprey’s Personal Fitness Journey </p><p>• <strong>03:43</strong> The Efficiency of REHIT Training </p><p>• <strong>05:03</strong> Practical Applications and Accessibility of REHIT </p><p>• <strong>08:22</strong> Addressing Common Concerns and Misconceptions </p><p>• <strong>11:25</strong> The Future of Fitness: REHIT and Beyond </p><p>• <strong>18:29</strong> Scientific Validation and Real-World Results </p><p>• <strong>31:53</strong> Clinical Trials and Tech Integration </p><p>• <strong>32:06</strong> Upgrade Labs and CAROL Bike </p><p>• <strong>33:00</strong> Mitochondrial Effectiveness and Insulin Sensitivity </p><p>• <strong>36:05</strong> Zone Two Training vs. High-Intensity Training </p><p>• <strong>42:02</strong> REHIT for Perimenopausal Women </p><p>• <strong>48