Running a marathon is a bad idea—and in this episode, I explain why. I react to a shocking new study suggesting that during a marathon, the brain may actually consume myelin (the fatty insulation around nerve fibers) for fuel once glycogen stores run low.

The researchers reassure us that the brain “bounces back naturally over time.” I’m not so reassured. I talk about the acute damage caused by marathon running—not just to the brain, but also to the heart, kidneys, hormones, immune system, and inflammatory response.

I also go deeper into the long-term concerns around extreme endurance training: the diminishing returns of chronic cardio, why endurance training often fails as a fat-loss strategy, the “struggle and suffer” ethos of the endurance scene, and the opportunity cost of spending all your fitness energy shuffling down the road instead of building strength, power, explosiveness, and resilience. I explain why “what doesn’t kill you makes you stronger” is often misunderstood through the lens of hormesis and cumulative stress load, and finish with my preferred approach to lifelong fitness and longevity: walk more, lift weights regularly, and sprint once in a while.

TIMESTAMPS:

Running a marathon is a bad idea. Running those 26 miles can transform your brain. [01:05]

Myelin is the fatty insulation around nerve fibers used as fuel when we run out of glycogen during a marathon. The brain fog one gets is caused by the loss of myelin. [02:24]

Brad is looking at the stress on the brain as a result of metabolic myelin plasticity. [04:35]

Long distance running places significant demands on the body and brain. [07:10]

Numerous critical health immune inflammatory and cardiac biomarkers get temporarily blown off the charts even in the best prepared athletes, but more so in the recreational athletes. [09:45]

If you were to go directly from crossing a marathon finish line to the nearest emergency room and have blood drawn, you would have the same lab results as someone suffering from a myocardial infarction, a heart attack. [10:47]

There's also prominent research revealing how the immune system is suppressed for a significant period after the marathon. [14:15]

The essence of peak performance and achieving bucket list goals is to do them correctly rather than drag a tired, unprepared body to the finish line. [17:58]

One study suggests that conducting around two and half hours a week of endurance exercise comfortably paced is sufficient. [20:07]

There's extensive and mounting research that endurance training simply does not work for fat loss. [22:14]

An overuse injury is an obvious sign that the body is being overwhelmed and the training is not appropriate. [27:38]

The obligate runner is one who has taken to the extremes similar to the anorexic needing control. [29:10]

Effort and struggle are deeply satisfying when you're pursuing peak performance goals with honor and maintaining constant vigilance over your mental and physical health. [31:52]

Putting all that energy to a narrow fitness goal like endurance training, precludes other far more valuable fitness endeavors. [33:53]

Broad-based, full body fitness is the key to general health, vitality and longevity. Endurance competency is a small sliver of the big picture. [35:10]

Shoes enable poorly adapted people to do an activity that they really shouldn't be doing. [37:16]

Running a marathon is such an extreme challenge and it is very difficult to train in an appropriate sensible manner. A low-key casual approach can even lead to excellence in endurance training provided we don't succumb to these crazy influences that turn you into an obligate runner. [39:24]

Is the old saying; What doesn't kill you, makes you stronger." really accurate? [43:47]

You do not have to have sore muscles to grow stronger. Stress and breakdown are a byproduct of something you're doing to try and improve your health [46:27]

You can get a detox effect from fasting but you can also improve your digestive system by just changing your diet. Or you can try a cold plunge. [47:24]

Benefits come from the mechanical load or the cardiovascular load not the damage to the brain you get when you are overdoing it. [50:46]

When thinking of a marathon, think about the pounding of the cement for 26 miles rather than a century bike ride or long distance hiking with low or no impact on your feet. [51:42]

We want to create a fitness program where you spend a lot of energy on resistance training for your muscles and dedicate a portion to explosive efforts. [55:39]

LINKS:

• Brad Kearns.com
• BradNutrition.com - 20% OFF Your First Order!
• B.rad Superdrink – Hydrates 28% Faster than Water—Creatine-Charged Hydration for Next-Level Power, Focus, and Recovery
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• B.rad Whey Protein Superfuel - The Best Protein on The Planet!
• Brad’s Shopping Page
• BornToWalkBook.com
• B.rad Podcast – All Episodes
• Peluva Five-Toe Minimalist Shoes - Save 10%
• TED Tallk by James O'Keefe, M.D.
• Brad's Podcast with Dr. Joan Ifland
• Brad's Podcast with Cynthia Monteleone
• Jay Feldman Wellness.com
• WHAT RUNNING A MARATHON DOES TO YOUR BRAIN 
• Does Marathon Running Harm the Brain? New Study Reveals Surprising Answer!
• Cognitive Benefits of Open-Skill Sports in Childhood: Evidence from the ABCD Study

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