Mark’s Daily Apple veterans are familiar with one of the most controversial and impactful posts ever published to the site, Mark’s 2007 treatise called A Case Against Cardio. The article changed my life and caused me to rethink many of the flawed assumptions about endurance training that have been indoctrinated into conventional stupidity for decades. Follow up posts like this one dig deeper into the do’s and don’ts of cardiovascular exercise, as does the Primal Endurance book and online multimedia education program.
The title of this article is a quote from Paleo movement pioneer Dr. Art De Vany. Far from a tongue-in-cheek wisecrack, De Vany detailed in a 2017 podcast interview on the Tim Ferriss Show how steady state cardio is in conflict with your genetic expectations for health.
This post will provide an update on the mounting science suggesting that steady-state cardio need not, and probably should not be the centerpiece of your fitness endeavor. Plus, I’ll include suggestions to transform your routine steady state cardio workouts into fun, creative sessions that deliver broader and more impactful fitness benefits with less downside risk of drifting into chronic patterns.
Spoiler alert: I’m going to suggest you take your typical steady state jogging session at a chosen pegged heart rate and add some walking (gasp!), pace variations, and alternate activities like explosive bursts and drills that hone balance, flexibility, and mobility.
I’ve been doing steady state cardio for 40 years (gulp) as a high school and collegiate runner, pro triathlete, and Speedgolfer such that heading out the door for a morning jog at a comfortable aerobic heart rate has been programmed into habit at the same level as brushing my teeth.
High Jump as an Eye Opener
In recent months I have rekindled a longtime passion for the fabulous track field discipline of high jump. I’m trying to raise the bar in life in every way, so why not? It’s (arguably) the most beautiful and complex of track and field events because of the disparate skills and technical mastery it requires. You need speed and power for starters, but unlike Usain Bolt in the 100 meters or Carl Lewis in the long jump, high jumpers face the complexity of transferring energy from the horizontal plane (i.e., running fast) to the vertical plane (i.e., jumping high) with a difficult change of direction and different application of forces (represented by the curved approach) required to fly backward and bend the body virtually in half to clear the bar.
Consequently, I’ve been taking the opportunity of my usual ho-hum morning run to perform an assortment of creative drills and skills for high jump, and the experience has been a revelation. My outings are more fun, challenge my central nervous system to execute good technique for complex movements, and stimulate my creative energies instead of just a brain flatline outing with jogging. Actually, there’s nothing wrong with the latter in hyperconnected life, but the novel stimulation of a varied workout provides a greater sense of excitement heading out the door and a greater sense of satisfaction after the session.
Perhaps most importantly, getting off the figurative treadmill (some of you will be getting off a literal treadmill if that’s your go-to gym workout) protects you against the high-risk elements of steady state cardio. We talk about football being too violent of a sport for an evolved society (well, at least I do…), but steady state cardio is right there in the high- risk category. Enthusiasts of all ability levels engage in chronic conditions exercise patterns that lead to breakdown, burnout, illness, and injury to a shocking degree. A survey by Runners World magazine revealed that an astonishing 80 percent of the 30 million runners in America get injured in a given year—even with no tackles allowed on the marathon route!
Risks of Overtraining
More disturbing are the cardiovascular disease risk factors associated with devoted endurance training over the long run. Sisson and I keep a registry of endurance athletes (including numerous world champion caliber performers) who have suffered from serious heart problems either during, or in some cases years after retirement from elite competition. While Christopher McDougall’s book Born to Run became a bestseller, I believe the legacy of Homo sapiens as a magnificent endurance machine has been twisted out of context today. Indeed, humans evolved some incredible cardiovascular endurance advantages, such as bipedal locomotion and evaporative cooling. While this gave us an edge against other predators, evolving a complex brain was orders of magnitude more significant to rising to the top of the food chain.
It’s more anthropologically accurate to say that humans were born to move frequently at a slow pace, while possessing the ability to perform magnificent endurance feats once in a while. The amazing YouTube documentary, The Great Dance, is believed to be the first filmed account of a bonafide persistence hunt. The program follows a member of the San Bushmen tribe, modern day hunter-gatherers in Africa’s Kalahari desert, tracking an kudu antelope across the desert for four hours in 100-degree-plus temperatures. Finally, the exhausted antelope is easily caught and speared to death in place—another victory for the endurance kings of the planet! The important take away for me is that the hunter didn’t lace up his moccasins the following day to put in an easy eight-miler like a modern runner might. Life or death endurance feats (indeed, the San Bushmen clan in the flick had not feasted in quite a while due to drought) are in a different category from averaging 50-mile weeks and piling up finisher medals.
Endurance as a Once-in-a-while Endeavor
There’s nothing inherently unhealthy about pushing your limits once in a while to bag an antelope or a 50k finisher medal. It’s both physically and psychologically healthy to get out of your comfort zone now and then, counterbalance the luxuries, conveniences, and excesses of modern life, and trigger a fantastic adaptive fitness response to an extreme challenge. Mark, who finished dozens of marathons in his running career, recommends to aspiring marathoners that they complete just two marathons: The first one is to finish; the second one to improve your time! Then, check “26.2” off your bucket list with the acknowledgement that the stress of repeatedly training and competing in a footrace of that distance is going to compromise your hormonal, musculoskeletal, immune, and endocrine systems without a doubt.
After all, the marathon was introduced as an event in the first modern Olympics in 1896 in Athens to commemorate the saga of the Athenian messenger soldier Pheidippides. As legend has it, 2,500 years ago Pheidippides ran 25 miles from the battlegrounds of Marathon to Athens, burst into the Acropolis and excitedly reported, “Rejoice, we conquer!,” then promptly dropped dead on the spot. Interestingly, Greek historians now assert that the story is not true. Pheidippides is believed to have actually run from Athens to Sparta and back to Athens—a total of 300 miles over the course of four days!—to relay important battle information. It’s believed that a different messenger did the Marathon to Athens jaunt and dropped dead after delivering the news.
In any case, we can draw a clear distinction between honoring our Born to Run genetics to keep fit for life versus following the prevailing “chronic cardio” approach to endurance training that compromises health and accelerates the aging process. Like any other muscle, the heart requires an optimal balance of stress and rest to thrive. It’s unthinkable to rip your biceps to shreds doing exhaustive sets of curls day after day with insufficient rest, but we routinely treat our cardiovascular system with much less TLC than our traps and guns.
The Dangers of Excessive Cardio: Your Heart and Beyond
Dr. Peter Attia, longevity expert, host of The Drive podcast, and accomplished ultra-endurance athlete, explains what’s going on inside:
“Challenging endurance workouts cause an increase in both heart rate and stroke volume [amount of blood pumped out per beat of the heart], by stretching the heart larger to pump more blood per beat. This amazing organ can quickly go from pumping three to five liters of blood around our body per minute at rest to 30 liters per minute during very intense exercise. Unfortunately, the right side of the heart, which pumps only against the low-resistance lungs, and is far less muscular than the left ventricle, is more vulnerable to damage from chronic amounts of high cardiac output training. So while short bouts of this intensity don’t appear to cause lasting damage on the heart, prolonged activity does—at least in susceptible individuals. The so-called chronic cardio patterns can cause the right ventricle to become scarred from excessive use and insufficient recovery. This scarring can lead to cardiac arrhythmias, especially atrial fibrillation, and even sudden death in athletes who have no evidence of atherosclerosis.”
Chronic Cardio and Mitochondria
Beyond scarring and inflaming the heart, there are many other ways to contribute to your demise with chronic cardio. You can gather these under the heading of the “Extreme Exercise Hypothesis,” a concept which has recently been scientifically validated and studied with increasing urgency. Beyond blowing out your heart, Attia describes how mitochondria can become damaged by chronic exercise, a scary story of accelerated aging and health destruction to ponder: “When mitochondria are heated up too frequently for too long, proteins become denatured (destruction of the tertiary elements of the molecule, causing dysfunction) and mitochondrial DNA leaks out of cells.”
This phenomenon is highly problematic because mitochondrial DNA is perceived as a foreign agent to your body. They are different from cellular DNA and strikingly similar to bacteria cells. When mitochondrial DNA leak into the bloodstream, your immune system is confused into launching an attack against a perceived invader. This triggers an inflammatory autoimmune response (essentially the body attacking itself), a sustained pattern of which accelerates aging and disease risk. Emerging science on the gut microbiome reveals that this leaking of mitochondrial DNA into the bloodstream is particularly prevalent in the intestinal tract via a leaky gut. As you likely know from reading articles like this one on MDA, leaky gut is driven strongly by eating offensive foods like gluten and toxic seed oils, but endurance training is also a risk factor. When you elevate heart rate and raise body temperature for a prolonged workout, your gut becomes inflamed and permeable as a matter of course to respond to the workout stimulus—especially in hot temperatures. Dangers are no doubt magnified when you try to shove sugary drinks, bars, gels and blocks into said intestinal tract while blood is shunted to the extremities for performance.
“But wait, there’s more!” A 2015 Outside Magazine article titled, Running on Empty chronicled the hidden dangers of ultramarathon running, describing how numerous elite performers suddenly disappear from the face of the earth (or at least the starting line), victims of extreme burnout. A Wall Street Journal article titled, One Running Shoe In The Grave detailed how older athletes have a higher risks of health disturbances related to ambitious endurance training.
A 2015 Velo News article titled, Cycling To Extremes, explained how longtime competitive cyclists are especially vulnerable to developing atrial fibrillation because they can sit and pedal for hours on end with their heart rates pegged at a medium-to-high rate. Hence, they are unrestrained by the pounding that limits a runner’s total weekly exercise output.
Hence, other low impact sports like rowing or cross-country skiing fall into the same risk category as the cyclists. Interestingly, the weightlessness and body temperature stability with swimming lessens the strain on the cardiovascular and other body systems, providing a measure of protection to high volume swimmers.
In the book, The Great Cardio Myth, strength and conditioning expert Craig Ballantyne details how cardio exercise is ineffective for weight loss, heart disease prevention, and longevity; rather, it can have an opposite effect in each area. In cardiologist Dr. James O’Keefe’s TED Talk, “Run for your life! At a comfortable pace, and not too far,” he explains that aerobic health and disease protection are easily optimized with a couple hours of easy cardio per week, and that anything beyond that seemingly paltry total departs from the category of “health” and “longevity” and into the realm of potentially compromising health, increasing disease risk and literally accelerating cellular aging. What’s more, marketing forces brainwash serious enthusiasts to believe they aren’t really legit until they finish a marathon or triathlon. For well intentioned novices heading to the gym, they are subjected to a boot camp experience (literally!) to the extent that they associate the gym, and a fitness lifestyle, with pain and suffering.
A Better Way to Train
Alas, if you love endurance training and racing for the pursuit of peak performance, the enjoyment of nature, social connection, and the psychological satisfaction and confidence gained from pushing yourself, these huge benefits must not be discounted. It’s just a matter of rejecting the conventional stupidity of “more is better” and adopting a Primal Endurance-style holistic approach featuring healthy eating (escape carb dependency to become fat- adapted), aerobic emphasis with strict heart rate guidelines, complementary fitness activities such as flexibility/mobility exercises and brief, explosive exercises, and maintaining exceptional overall stress-rest balance in life. With a correct approach, you can preserve your health, have more fun, and still manage to perform well at endurance or ultra endurance activities.
Granted, it’s an extremely tricky balance for the Type-A subjects who populate the starting line. Sedentary observers from the peanut gallery laud the “focus and discipline” exhibited by their endurance athlete neighbor. Ironically, most of the focus and discipline required to excel in endurance sports must be directed toward restraint, stress-rest balance, and backing off when necessary.
Things are getting better as more and more enthusiasts appreciate the sensibility of a less stressful approach focused on aerobic development and minimizing the exhausting, depleting workouts (Hawaii Ironman legend Dave Scott describes them as “kinda hard”) that compromise health and increase burnout risk. It’s heartening to see the rise in popularity for the work of aerobic training pioneer Dr. Phil Maffetone, author of The Big Book of Endurance Training and Racing. Phil has been talking about the now widely accepted “180 minus age” MAF (stands for Maximum Aerobic Function; it’s also a play on Phil’s last name) nearly 40 years. He’s coached some of the greatest endurance athletes of all time, including triathlon legends Mark Allen, Mike Pigg and Tim DeBoom. Alas, Phil’s urgent message to slow down has received more lip service than strict implementation until recent years. As more and more athletes accumulate results with a sensible approach, the tide is finally turning.
In the second part of this article, we will cover ways to depart from steady state suffering to enjoy fun, challenging workouts that broaden your fitness competency without the downside risks of chronic cardio. Check back next week, and get ready to jump for joy!
About the Author
Brad is a New York Times bestselling co-author (with Mark!) of The Keto Reset Diet, hosts the B.rad podcast, is a Guinness World Record holder in Speedgolf, the #1 ranked US masters age 55-59 high jumper in 2020, and a former U.S. national champion and #3 world-ranked professional triathlete. Visit BradKearns.com to connect with Brad.