You can have your training, nutrition, and supplement stack dialed in and still be neglecting the strongest predictor of how long and how well you live: your cardiovascular fitness. Low cardiorespiratory fitness has been linked to more avoidable deaths than smoking, obesity, and diabetes combined, yet lack of time remains the number one reason people skip the work that improves it.

We dive deeper into this in The Kris Gethin Podcast with Ulrich Dempfle, CEO and co-founder of CAROL Bike, breaking down how two 20-second sprints, done just a few times a week, can raise VO2 max and improve metabolic health. We also chat about whether cardio really kills muscle gains, why expensive biohacks cannot replace a strong cardiovascular base, and why Ulrich rates zone 2 training a 5 out of 10.

Ulrich Dempfle is the CEO and co-founder of CAROL Bike, the AI-powered exercise bike built on Reduced Exertion High-Intensity Interval Training (REHIT). A mechanical engineer by training and former McKinsey and PwC management consultant, he developed CAROL in collaboration with leading exercise scientists.

What's Discussed:

(9:08) Why the strongest predictor of healthspan is the one people skip most.

(14:50) Why low cardio fitness may be deadlier than smoking, obesity, and diabetes combined.

(15:53) Why mitochondrial peptides cannot replace the basics.

(17:42) How much VO2 max can improve in 8 to 20 weeks.

(23:58) What actually happens during two 20-second sprints.

(38:48) Why so many biohackers try to buy their way around the hard work.

(44:00) How your phone is costing you sleep.

(45:04) Calories, the afterburn, and where cardio fits in fat loss.

(48:29) GLP-1s and the skinny-fat trap.

(51:50) How short sprints improve blood sugar control and insulin sensitivity.

(57:37) Two sprints vs. 60 sprints: when more is not better.

(1:00:44) How to fit sprint cardio into a five-day lifting week.

(1:05:30) What to track to prove it is working.

(1:11:04) Rapid fire: cardio and muscle gains, zone 2, and VO2 max.

If you train hard, care about recovery, and want to see the tools, supplements, and products I personally recommend, head to krisgethin.com/pages/recommendations

To receive my free book, A Guide to Biohacking, leave an honest review on the platform where you listen to the podcast, then email a screenshot to info@krisgethin.com

Thank You to Our Sponsors!

CAROL Bike: Want a science-backed cardio workout that takes just five minutes? Head to carolbike.com/kris and use code KRIS for the best available offer.

Structured Water by Natural Action: Want to upgrade the quality of the water you drink every day? Head to naturalaction.com and use code KRIS at checkout.

Hydrogen Rich Water: Want an easy way to add molecular hydrogen to your hydration routine? Head to drinkhrw.com/pages/h2-in-sports and use code GETHIN for 10% off.

Find More From Kris Gethin:

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

2 Shred: unmatchedsupps.com/products/2shred

Find Out More About Ulrich Dempfle and CAROL Bike:

Website: carolbike.com

Instagram: @thecarolbike

YouTube: youtube.com/c/CAROLbike

Kris Gethin shares his personal journey and expert insights on how to effectively manage fat loss and maintain muscle after 40, emphasizing the importance of adapting strategies to biological changes.

Chapters

00:00 Introduction to Fat Loss Challenges After 40
02:24 Stress, Cortisol, and Fat Storage
04:36 Cellular Metabolism and Mitochondrial Health
06:33 Using Blood Glucose Monitoring for Better Results
07:01 Hormone Optimization Through Diet and Lifestyle
07:54 Sleep Optimization and Circadian Rhythms
08:20 Biohacking Techniques for Aging Gracefully
09:20 The Importance of Outdoor and Recreational Cardio
10:15 Adapting Strategies to Your Biological Feedback
10:43 Final Thoughts and Practical Advice for Over 40 Fitness

Resources

Carol Bike - uses artificial intelligence to personalize high-intensity workouts in real time, delivering an efficient, science-backed cardio session in just minutes.
Code: KRIS - save $300

Better Bodies / GASP — Performance-focused gym apparel and training gear that I have been wearing since 2005 - designed for serious lifters.
Code: KRIS15 — 15% off your order

Bahé Trainers — Comfortable running, training and hiking shoes featuring grounding/earthing technology designed to create an electrical connection with the earth.
Code: KRIS15 — 15% off your order

Nutrition Solutions — Prepared grass fed, humane raised, organic and antibiotic free meal solutions that make it easier to stay consistent with your nutrition when life gets busy. I have used them weekly since 2015
Code: LEGACY20 for your discount

Find More From Kris Gethin

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

Tik Tok: @krisgethin

You can have your training, nutrition, supplements, and recovery dialed in and still overlook one of the most powerful inputs your body receives every day: light. From the moment you wake up to the screens, LEDs, office lighting, and nighttime exposure around you, your light environment may influence your circadian rhythm, recovery, sleep, and performance.

In this episode, Alex Kikel and I break down how different wavelengths of light interact with the body, why morning and evening light matter, and where red and near-infrared light may fit into a performance-focused routine. We also look at what you can do for free, what is worth spending money on, and where biohacking starts becoming unnecessary overkill. The goal is simple: understand the mechanism, control the basics first, and use technology only when it actually adds something.

What's Discussed:

(12:47) Why light should matter for performance and body composition.

(19:14) Blue light, near-infrared light, and what your environment is missing.

(23:48) The simplest light protocol you can do for free.

(34:15) How light fits into fat loss, muscle, and recovery.

(42:46) Why the first few minutes of your morning matter.

(54:20) Why sleep supplements cannot fix a bad nighttime environment.

(57:08) Using red and near-infrared light around your workouts.

(1:06:45) Red light for skin, hair, and recovery protocols.

(1:13:35) Light habits: overrated or underrated.

(1:17:28) The $0, $100, and $10,000 light protocol.

(1:20:29) Why jumping straight to expensive biohacks can backfire.

If you train hard, care about recovery, and want to see the tools, supplements, and products I personally recommend, head to krisgethin.com/pages/recommendations

To receive my free book, A Guide to Biohacking, leave an honest review on the platform where you listen to the podcast, then email a screenshot to info@krisgethin.com

Thank You to Our Sponsors!

Structured Water by Natural Action: Want to upgrade the quality of the water you drink every day? Head to naturalaction.com and use code KRIS at checkout.

Hydrogen Rich Water: Want an easy way to add molecular hydrogen to your hydration routine? Head to drinkhrw.com/pages/h2-in-sports and use code GETHIN for 10% off.

Find More From Kris Gethin:

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

2 Shred: unmatchedsupps.com/products/2shred

Find Out More About Alex Kikel:

Website: theprepcoach.com/

Instagram:@alex_kikel

YouTube: @alexkikelTPC

TPC Army: skool.com/tpcarmy/about

Kris Gethin shares his personal journey through motivation struggles, the importance of discipline, and how to adapt training routines to maintain health and purpose. This episode offers practical insights for anyone facing a dip in enthusiasm for fitness and life.

Chapters

00:00 Introduction to Kris Gethin's Motivation Struggles
01:54 Why Motivation Cannot Be the Foundation of Your Behavior
04:09 The Changing Reasons for Training as We Age
06:56 The Spiritual and Stewardship Perspective on Taking Care of the Body
11:09 The Power of Discipline and Changing Your Training Routine
14:59 Acting Without Waiting for Motivation to Return
17:52 Recap: Key Lessons for Maintaining Consistency
19:46 Final Thoughts: Responsibility and Moving Forward

Resources

FightCamp — An interactive at-home boxing and kickboxing training system with expert-led workouts, equipment, and performance-tracking technology. I often use this as my functional workout on non-training days
Code: GETHIN10 — 10% off your order

Better Bodies / GASP — Performance-focused gym apparel and training gear that I have been wearing since 2005 - designed for serious lifters.
Code: KRIS15 — 15% off your order

Bahé Trainers — Comfortable running, training and hiking shoes featuring grounding/earthing technology designed to create an electrical connection with the earth.
Code: KRIS15 — 15% off your order

Nutrition Solutions — Prepared grass fed, humane raised, organic and antibiotic free meal solutions that make it easier to stay consistent with your nutrition when life gets busy. I have used them weekly since 2015
Code: LEGACY20 for your discount

Find More From Kris Gethin

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

Tik Tok: @krisgethin

You can nail your training, nutrition, supplements, and sleep routine and still overlook one variable that surrounds you all day: your technological environment. Phones, Bluetooth, Wi-Fi, wearables, cars, and constant connectivity may be adding another layer of physiological stress at the exact time you are trying to recover, perform, and switch your nervous system off.

In this episode, Alex Kikel and I break down how EMFs interact with the body, why professional athletes are beginning to pay attention, and where exposure may be affecting recovery and performance. More importantly, we look at what you can realistically control, what may be overkill, and how to improve your environment without turning optimization into another source of stress.

What's Discussed:

(02:29) Why pro athletes are paying attention to EMFs.

(04:21) Coherent vs. non-coherent EMFs.

(15:26) EMFs, recovery, and fat loss.

(39:23) EMF exposure inside modern cars.

(50:53) Keeping your phone against your body.

(52:31) Phones, EMFs, and your sleep environment.

(58:17) When wearables create more stress.

(1:11:49) When biohacking becomes counterproductive.

(1:22:07) EMF habits: overrated or underrated.

If you train hard, care about recovery, and want to see the tools, supplements, and products I personally recommend, head to krisgethin.com/pages/recommendations

To receive my free book, A Guide to Biohacking, leave an honest review on the platform where you listen to the podcast, then email a screenshot to info@krisgethin.com

Thank You to Our Sponsors!

Structured Water by Natural Action: Want to upgrade the quality of the water you drink every day? Head to naturalaction.com and use code KRIS at checkout.

Hydrogen Rich Water: Want an easy way to add molecular hydrogen to your hydration routine? Head to drinkhrw.com/pages/h2-in-sports and use code GETHIN for 10% off.

Find More From Kris Gethin:

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

2 Shred: unmatchedsupps.com/products/2shred

Find Out More About Alex Kikel:

Website: theprepcoach.com/

Instagram:@alex_kikel

YouTube: @alexkikelTPC

TPC Army: skool.com/tpcarmy/about

Creatine has long been associated with bodybuilding and strength training — but its potential benefits extend far beyond the gym. In this episode, Kris Gethin dives into the evolving research on creatine's impact on cognitive function, mental health, and even its role during periods of sleep deprivation.

00:00 Introduction to creatine's expanding benefits
02:16 Research on creatine and cognitive performance
04:31 Creatine's relevance for sleep-deprived individuals
06:44 Creatine's potential in anxiety and mental health
09:25 The challenge of increasing brain creatine levels
09:52 GAA as a precursor to enhance creatine levels
11:17 Research on GAA and cognitive performance
12:15 Future directions: brain-focused creatine research
13:09 Personal insights and practical applications of creatine
14:35 Conclusion and next steps for research and health

This content is for informational purposes only and is not medical advice. Talk to your doctor before starting any new supplement, especially if you are pregnant, managing a health condition, or taking prescribed medication for depression or other mood disorders.

Most bodybuilders have been taught to think about water in one way: drink enough of it and stay hydrated. So it makes sense that the real attention goes to the things we have been told actually move the needle: protein, carbs, creatine, electrolytes, pre-workout, recovery, blood work, and everything else in the stack. But once you start looking at what water is doing inside muscle tissue, what can be in the water you are drinking, and how much of it you put through your body every day, it becomes difficult to treat it as just the liquid you wash your supplements down with.

In this episode, Alex Kikel joins me to bring a completely different perspective to something most of us have never had a reason to question. We get into why the type of water you drink could matter for muscle contractions, pumps, glycogen storage, recovery, and cognition, along with what could be coming from tap and bottled water. We also get into structured water, filtration, remineralization, hydrogen water, and then take it straight into contest prep with fluid retention, sodium, creatine, and why cutting water can sometimes leave a bodybuilder looking flatter instead of tighter.

Alex has spent 14 years working with and tracking thousands of people, including Olympic, NBA, and NFL athletes. His experience across health, physique, and high-level performance gives us a very different way to look at something bodybuilders use every day but rarely treat as part of the protocol itself.

What's Discussed:

04:55 Why the water inside your muscles could affect contractions, pumps, strength, and how much you get from every rep.

11:34 "Structured" vs. "dead" water, and why simply drinking enough may not be the whole hydration story.

20:40 What drinking from plastic every day could be exposing you to, and how realistic it is to avoid microplastics.

25:32 Can light, minerals, vortexing, and water-structuring devices actually change the water you drink?

46:11 Why the water in your shaker could change how your pre-workout, electrolytes, carbs, and supplements perform.

49:24 What hydration has to do with brain fog, memory, mental performance, inflammation, and energy.

58:24 Hydrogen water, fat loss, water retention, sodium, creatine, and the peak-week water mistakes that can ruin your final look.

If you train hard, take supplements, care about recovery, or simply drink litres of water every day, this episode will make you look at what is in your bottle very differently.

To receive my free book, A Guide to Biohacking, leave an honest review on the platform where you listen to the podcast, then email a screenshot to info@krisgethin.com

If you train hard, care about recovery, and want to see the tools, supplements, and products I personally recommend, head to krisgethin.com/pages/recommendations

Thank You to Our Sponsors!

Structured Water by Natural Action: Want to upgrade the quality of the water you drink every day? Head to naturalaction.com and use code KRIS at checkout.

Hydrogen Rich Water: Want an easy way to add molecular hydrogen to your hydration routine? Head to drinkhrw.com/pages/h2-in-sports and use code GETHIN for 10% off.

Find More From Kris Gethin:

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

2 Shred: unmatchedsupps.com/products/2shred

Find Out More About Alex Kikel:

Website: theprepcoach.com/

Instagram:@alex_kikel

YouTube: @alexkikelTPC

TPC Army: skool.com/tpcarmy/about

As we age, our bodies change — and so should our approach to training. In this episode, Kris Gethin shares his journey from competitive bodybuilding to a more functional, sustainable fitness routine as he navigates his 50s. He breaks down his current training split, why recovery now drives his results more than volume ever did, and how he stays mentally locked in even as the workouts themselves have changed.

• Why Kris moved away from six-day, heavy-lifting training as he entered his 50s
• How his goals shifted from pure muscle-building to functionality and long-term health
• The training split he follows now, and why fewer days doesn't mean less intensity
• What actually drives hypertrophy at this stage of life (hint: it's not more volume)
• How he approaches sleep, stress, and nutrition to support recovery
• Why seeking out discomfort is still central to his mindset, even with a lighter schedule

Chapters

00:00 Introduction and Kris Gethin's background
01:53 Training in his 30s and 40s versus now at 50
04:12 His current workout split and modifications
06:05 Impact of aging on recovery and joint health
07:57 The role of hormonal health and lifestyle factors
09:51 Changes in diet and supplementation over the years
12:12 Maintaining mental intensity and motivation
14:04 Making workouts more challenging and functional
15:52 Final thoughts and advice for aging athletes

Resources

FightCamp — An interactive at-home boxing and kickboxing training system with expert-led workouts, equipment, and performance-tracking technology. I often use this as my functional workout on non-training days
Code: GETHIN10 — 10% off your order

Better Bodies / GASP — Performance-focused gym apparel and training gear that I have been wearing since 2005 - designed for serious lifters.
Code: KRIS15 — 15% off your order

Bahé Trainers — Comfortable running, training and hiking shoes featuring grounding/earthing technology designed to create an electrical connection with the earth.
Code: KRIS15 — 15% off your order

Nutrition Solutions — Prepared grass fed, humane raised, organic and antibiotic free meal solutions that make it easier to stay consistent with your nutrition when life gets busy. I have used them weekly since 2015
Code: LEGACY20 for your discount

Find More From Kris Gethin

Website: krisgethin.com/

Instagram: @krisgethin/

YouTube: youtube.com/krisgethin

Tik Tok: @krisgethin