Searching For The Cardio Code

One of my fitness mentors is Chris Highcock from Conditioning Research and author of Hillfit. He always seems to be a year or two ahead of me when it comes to fitness interests and knowledge.

In a comment recently, he referenced a book called The Cardio Code that makes the case for why the science is clear that cardio is necessary for heart health and that lifting weights or even lifting weights in an interval setting is not enough. If anyone else had posted the link, I would have dismissed it and moved on, but it was Chris, so I fired up Bing and did a search.

The Cardio Code was released in 2014, but unfortunately only as an iBook on Apple iTunes. No paper. No Kindle. I dusted off my version 1 of the iPad only to discover I can’t update to the latest iOS version in order to read the book. And since I use Windows and not Mac, I can’t read the book on my laptop. I really do not want to have to read a 270-page technical book on my iPhone.

Now there may be a way to buy the book and convert it to a Kindle-friendly format, but every time I’ve done that in the past, the formatting has been a disaster.

Why wouldn’t the author put the book up on Amazon? There are services to handle both the conversion to Kindle and print-on-demand.

I discovered the author’s website*, which to be kind is “a piece of crap”. More embarrassing than McGuff’s Body By Science site before the “Chinese hackers” got to it. 🙄 Sorry, I’m a little opinionated on this topic. See The Digital Graveyard of My Health and Fitness Mentors for details.

*site down as of April 2021

I located a January 2017 podcast interview with Dr. Kenneth Jay on Leo Training. You can hear that here. The cardio portion of the interview starts around 19 minutes. Although his publishing strategy and website are terrible, his arguments impressed me.

My bias against cardio took a serious blow. Now perhaps someone in the HIT community far smarter than me can find flaws or disagreements with Dr. Jay, but I couldn’t. I still want to read the book or something to better understand this topic, but I’m not buying a new iPad to make that happen.

Not giving up, I went to the Wayback Machine and found an earlier version of the Cardio Code website. A much better version too!

Some highlights from this page:

  • Cardio is defined as exercise or training to make your heart work better.
  • The goal is to improve the pumping- and blood delivery capacity of the heart to the working muscles.
  • The best stimulus to your cardiovascular system is when you DO NOT limit blood flow back to the heart.

Why not just lift weights faster?

The problem arises with the muscular tension used to lift the weight. Because blood delivery to the working muscles depends heavily on perfusion of the muscle (meaning: can the blood actually get to the muscles that need it?) the oxygen rich blood has a hard time getting into the contracting muscle as it (the muscle, that is) will squeeze the blood vessels shut. The vessels may not close completely (that depends on duration and intensity of the contraction) but the blood will have a harder time getting to where it is needed. This is of course a major problem, which will increase heart rate in an attempt to force blood into the muscles. Unfortunately, the net result is only a large increase in blood pressure and a limited return of blood to the heart.

The rest of the blog post discusses VO2Max, intensity, and sports variations.

Right or Wrong? Undervalued or Overvalued?

As a once hardcode cardio skeptic, do I think Dr. Jay is correct? Likely, but for me, that is the wrong question to ask. He is smarter than me as are some of my fellow cardio critics. The way I am approaching this question is as an investor.

For at least a decade, I have heavily invested in the cardio is crap exercise portfolio. I achieved tremendous gains using HIT and walking, but it appears to be time to rebalance my portfolio. Cardio is undervalued to me at this time. It is worth pursuing.

I’d still like to read the book, but that may not be possible. In the meantime, I will ease into some cardio. What type? That will be the topic of my next post.

me on a bike

Time to dust off my old bike? 🤣


Add yours

  1. I’ve always gone back back to Bill Phillip’s Body for Life workout where he combines weights and cardio. I’ve found I feel and look my best following his simple but challenging program.

  2. MAS,

    Many threads ago, I tried to discuss cardio right here. No interest. Ditto Dr Darden and Corporate Warrior. HiTers hate the word cardio and are opposed to any type of cardio exercise. I lost interest in this site due to that lack of interest in cardiovascular conditioning.

    I have Dr Kenneth Jay’s book and it is indeed rich with information. Dr Phil Maffetone is a great source also.
    “Turn Up Your Fat Burn” Alyssa Shaffer is a great start read and discusses the important Ventilatory Threshold 1.
    Further study (free) of the Krebs cycle is important.

    A little amount of study will convince all objective persons that Dr McGuff’s Global Metabolic Conditioning is false reasoning.

  3. @Marc – Like others, you were ahead on me on this topic.

    I typically have a single primary fitness interest at any given time. Back in April when you commented on Dr. Jay, I was at the height of my frustration with my knee injury. A month later things would begin to improve, but at that time, the idea of cardio was the last thing on my mind.

    I’ll follow up on your reading recommendations. Thank you!


    “In a series of recent studies, we have defined the exercise intensity at which maximal fat oxidation is observed, called ‘Fatmax’. In a group of trained individuals it was found that exercise at moderate intensity (62-63% of VO2max or 70-75% of HRmax) was the optimal intensity for fat oxidation, whereas it was around 50% of VO2max for less trained individuals.”


    The talk test comes in handy … in other words, when cardiovascular exercise become strenuous and starts recruiting more muscle mass, more oxygen is needed to spin the Kreb’s cycle to make more ATP for energy. Labored breathing means you are now using the anaerobic and the aerobic energy pathways simultaneously as your lungs and CV can’t keep up with O2 demands. The Kreb’s cycle must replenish the anaerobic stores also.

    Cardio refers to the heart.
    Vascular refers to the blood supply network of the body
    The lungs decline significantly as we age …
    What can one do to counteract that?

  5. Actually , the above is wrong … The Kreb’s cycle must replenish the anaerobic stores also … as anaerobic glycolysis does not require oxygen and uses the energy contained in glucose for the formation of ATP and uses a different mechanism to replenish.

  6. Clarence Bass found the middle ground here:

  7. If you think about the various systems of the body, and which are rate limiting to health, it makes sense to build up the aerobic system in order to increase the rate and efficiency of its various processes. My reading indicates that it is the aerobic system that replenishes the anaerobic system trained with weights. Therefore, improving one’s aerobic capacity would enhance one’s ability to recover from intense physical effort.

    Resources I have seen that seem at least more knowledgable than most about how to develop those systems include Phil Maffetone (mentioned above) and Brian Mackenzie ( who focuses on nasal breathing. Other important resources on breathing are books on Buteyko breathing as well as the Oxygen Advantage by Patrick McKeown. What is generally under-appreciated is the role of carbon dioxide in breathing, and its role in oxygen uptake. Having the ability to tolerate greater carbon dioxide in the body helps with aerobic efficiency because it allows for more efficient oxygen update per breath.

    What I don’t enjoy about aerobic development (and I suspect is the case for many) is that it seems to require long stretches of exercise at sub-maximal efforts, which don’t get the endorphins pumping. Additionally, hypoxic exercise can be quite stressful also without the endorphins I find.

    I haven’t found a shortcut in any of the above, but I do think that combining Maffetone (focus on heart rate and fueling) and Mackenzie (focus on developing oxygen update efficiency) would help to accelerate that development.

  8. @Brock – Thanks for the resources. I just heard an interview with Brian Mackenzie last week, so all this info is coming my way now.

  9. I was wondering how long it would take for Clarence Bass to come up in the comments. He’s been using resistance training and aerobics for years.

    In fairness, though, the popular views of McGuff and Maffetone are a little oversimplified. I never read McGuff as saying – don’t do aerobics. Wasn’t one point in BBS that aerobics didn’t qualify as “exercise” under his rigorous definition of the word? Aerobics for McGuff (who road BMX as I recall), was activity, not exercise. Likewise, Maffetone doesn’t eschew all anaerobic exercise (again using his rigorous definition of “aerobic”). His point was that aerobic development needed to precede anaerobic training and that anaerobic training should never come at the sacrifice of aerobic work.

    That Wayback Machine post from Dr. Jay has a big focus on VO2 Max makes it sound as though intervals are in your future, MAS. Will we be seeing HIT meet HIIT?

  10. @Geoff – In that podcast interview, I recall Dr. Jay pushing for low-intensity aerobic conditioning and not HIIT.

    My plan is to build that aerobic base first, which I suspect will take a while and use what I learn to decide my next conditioning move.

    How I build that base is still unknown and will the topic of my next post.

  11. Even the vaunted Izumi Tabata had trainees do 30 minutes of steady state exercise at 70% VO2 Max once weekly.

    McGuff states that cardio doesn’t even really exist!

  12. Brian Mackenzie is associated with CrossFit Endurance and the book Unbreakable Runner, a program that promised success in ultra-endurance events with only small amounts of specific training, carried out at high intensity and supplemented with CrossFit workouts. He made some bold claims about placing in running ultra-marathons but, unsurprisingly, failed to deliver. In the ultra-running community he is considered something of a joke.

  13. @Mark – Thanks. This topic and landscape are going to be mostly new to me. I’ll need to filter their message and their intended audience with my needs.

    For the most part, I won’t know the good guys from the less-than-good, but if I test the ideas that interest me properly, I might be OK.

  14. I was able to buy a Kindle version of the cardio code in February of this year. It wasn’t via Amazon. Rather, it was a file purchased from a website called e-junkie. The link to that site was buried in a footnote at the bottom of Kenneth Jay’s old web site. The book was an interesting read, though I thought it was somewhat repetitive, and would benefit from professional editing. The formatting wasn’t great, but then the book was more like a long term paper or thesis, and didn’t need a lot of formatting.

    Unfortunately, since then, Kenneth Jay has revised his web site and the link has been removed. I think that he was using e-junkie to self publish the kindle format version. I expect he didn’t sell many copies via that web site, and probably discontinued it. Like you, I am puzzled as to why he didn’t sell it via Amazon.

    So, not much help for you, other than knowing that a kindle format copy of the book does exist. Finding one to purchase is another matter.

  15. @Craig – Thanks for the review. I don’t need to read it now. I can just trust the message and apply the ideas.

  16. You’re overthinking this. Just get a vo2max test and compare against the ACSM tables.

  17. Overthinking yhis? Overthinking cardio would be a first for HIT!

  18. Ondřej Tureček

    Feb 4, 2019 — 1:46 am

    As a medical student I side with Doug McGuff. Even at med school we learned that the stimulus for cardiovascular improvements comes from the periphery by working the muscles. Also, HIT doesn’t even raise the pulse as much as cardio, precisely because venous return and subsequent ejection fraction are higher, which is better for coronary perfusion.

    Here is more detailed explanation of cardiovascular adaptations by McGuff.

    It’s probably relatively old article, but honestly, this is basic physiology that doesn’t age, and here he goes into more detail than usual.

    Another look at activity that I found valuable is by dr. Steele.

  19. Ondřej Tureček

    Feb 4, 2019 — 1:55 am

    I meant stroke volume, not ejection fraction.

  20. Ondřej Tureček

    Feb 4, 2019 — 2:05 am
    A higher effort-based paradigm in physical activity and exercise for public health: making the case for a greater emphasis on resistance training

    This PDF is also a goldmine of evidence supporting Mcguff’s and Steele’s position, I highly recommend it. It is not just an effort of HIT folks, there are Andrew Vigotsky or Stu Phillips among the authors, so it’s objective.

  21. Ondřej Tureček

    Feb 4, 2019 — 4:48 am

    Here is a presentation where Doug McGuff talks about how view of cardio developed in HIT community over the years from pure anti-cardio zealotry to current stance which is that getting stronger and more muscular will make you spontaneously more active probably through myokine signalling and conversely forcing an obese/feagile person to do 10000 steps yields very little benefit.
    The segment starts at about 20:40.

  22. Ondřej Tureček

    Feb 4, 2019 — 6:29 am

    Kenneth Jay holds a degree in exercise physiology, I couldn’t find which university. I’d prefer a cardiologist (MD) to counter-argument Doug McGuff’s opinions.
    I had to look him up when I saw that dubious quote and sure enough – not an MD.
    Of course, it’s not Doug McGuff’s exact specialty either, but a medical doctor had to pass more rigorous exams from internal medicine – cardiology and has the knowledge base to build on if he is so inclined.

  23. @Ondřej – Great stuff. Thanks for sharing.

    I’m going to continue to hedge and do cardio for a few reasons:

    1- I don’t know which side is correct or if there is truth in both arguments.
    2- I’m getting breathing benefits from the elliptical trainer that is helping me when I lift, especially at higher levels of intensity and with push-ups.
    3- That “cardio zone” has been a missing part of my exercise portfolio for more than a decade. If there are benefits for me, then they are low-hanging fruit at this stage. As opposed to the mid-90s, when I did excessive cardio and I had yet to get the early benefits of strength training.

    This is my non-medical investor mindset. If I am wrong, then I’m likely not too wrong.

  24. Ondřej Tureček

    Feb 5, 2019 — 5:40 am

    that’s a good idea. Most MD’s would probably agree with you anyway, but for them this is mostly not an area of interest, so they just parrot what they heard 20 years ago during 2 hour lecture. But even the obesitologists and cardiologists that are up to date wear their trackers and are active. Again, if you ask them, they’ll be experts on cardiomyopathy types or stenting, not on exercise.
    I see things as a continuum, and to me, if you are covered by HIT, I don’t see much difference between a fast walk or a “cardio zone” elliptical etc. There is of course a difference in muscle involvement but again, the muscular side of things is covered by HIT.
    Overall it seems that your mortality and morbidity risk is affected by a) low bodyfat percentage, maybe 10-12% for men b) maximised lean body mass through smart and safe resistance training.
    At that point you will be generally active organically, whether you track or not. I often have 2000 steps in first 1 h in the morning, running up and down the house, brushing teth etc. But it doesn’t seem to matter much for health on top of previous points.
    The caveat is that light exposure and circadian rhythms affect sleep which affects obesity, mental health…but I don’t think at that point you have to hit a specific “zone” to get those benefits.

    In old “Project Total Conditioning”, participants that did just HIT lost more fat and gained more muscle than “HIT and cardio” group. “Cardio only” group was last by a huge margin. Not sure how reliable the study was but it’s quite interesting. Maybe more effort into workouts and less hunger?

  25. Ondřej Tureček

    Feb 5, 2019 — 1:34 pm

    I also revisited these particularly relevant videos.
    So let’s look at the original arguments: “…the oxygen rich blood has a hard time getting into the contracting muscle as it (the muscle, that is) will SQUEEZE the blood vessels SHUT. (Really? Are there possibly other mechanisms at place that prevent this?
    13706379_Regulation_of_skeletal_muscle_perfusion_during_exercise )
    “…the blood will have a harder time getting to where it is needed, which will INCREASE (really?Compared to HIIT cardio? Or steady state cardio of high effort? Hmmm…) heart rate in an attempt to force blood into the muscles. Unfortunately, the net result is only a large increase in blood pressure and a limited return of blood to the heart(Really? Well, the mechanisms are described in Skyler’s videos.).”

  26. @Ondřej

    Thanks for the shout out! I found one or two quibbles about what I said in those videos, mostly just being a completist and all, but I still think it’s relevant.

    Or as I said earlier: people like to get in the weeds about physiology. I got a graduate degree in this stuff so I know it well and understand why. However, if you’re leveraging for health, then the VO2max score takes into account the heart muscle (central adaptations i.e. heart rate and stroke volume) and the vascular/skeletal muscle changes (oxygen extraction i.e. a-v O2 diff).

    Only the most elite athletes are centerally limited (the heart muscle cannot keep up). The vast majority of us are limited by our ability to extract oxygen at the level of the working tissue.

    In short: get a VO2max test and compare it the ACSM tables. Add steady steady activity as “needed” or desired.

  27. Ondřej Tureček

    Feb 10, 2019 — 3:24 am


    Thanks for stepping in:-)
    What you’re saying sounds to me like general population would be better served by increasing frequency,duration / shortening rest periods of their HIT resistance training to improve VO2max and subsequently longevity. The VO2max test would confirm if they in fact are near their expected maximum.
    Low to medium intensity “cardio” would then have value for mental health and relaxation that might improve adherence in other areas like sleep or diet but wouldn’t be necessarily a “workout” we monitor or optimize for cardiovascular benefits.

  28. The last few comments on cardiovascular conditioning are far, far removed from Dr. Kenneth Jay’s views outlined in “ The Cardio Code.”
    These views are representative of viewpoints of HIT dogma that lacks the basics of anatomy and physiology.
    Furthermore, scientists and many of their studies do not agree with the above dogma.

    If resistance training, and circuit resistance training were appropriate training modalities for the cardiovascular pulmonary systems, then why is it not used for such the world over. Because resistance training is a poor way to condition the heart and lungs. You would think reasonable people would agree, but HIT has an agenda.

  29. Ondřej Tureček

    Feb 11, 2019 — 12:45 am

    Several years ago, all doctors said “do aerobics”. But today, if you visit medical lecture, they will recommend “cardio” (probably Borg scale level 13 effort) and weight training, will mention that the adaptation is driven from the periphery (working muscles). I also discussed this with elderly diabetologist doctor who told me the latest position is to make older diabetics strength train and not diet down, the primary focus is for them to not lose muscle at all costs.
    Again, “Dr.” Jay is noteven a medical doctor.
    The pendulum is shifting slowly and cautiously, as we need more robust data, but honestly, in my view it’s inevitable that strength straining will be the dominant recommended modality in the future.
    Obese patients who are treated at the endocrinology clinic use our medical faculty strenght training facilities and train there 4x/week. I’d choose a different programme but that’s just my preference.

    It’s precisely the knowledge of anatomy, physiology, biochemistry etc. that allows us to leave old dichotomies behind and provide patients with the safest, most effective and efficient methods possible.

    Could you explain to me how exactly is resistance training of sufficient effort inadequate to stimulate desired adaptations? I thought Skyler explained everything quite clearly.

  30. @ ALL misled HIT aficionados

    I have previously explained right here on this site why resistance training is insufficient for cardiovascular and pulmonary training needs. Please reread my posts carefully. Although any exercise is better than none, cardio is needed due to heart disease and the aging effects on the pulmonary organs.

    I will not debate OT further, because your debate tactics are lacking. The only thing that matters in a case method is facts and logic.

    You engaged in a dishonest debate tactic of stating why you are wrong without stating WHERE you are wrong. You stereotyped medical doctors as well as Other Doctors of certain disciplines. You were further dishonest with your characterization of Dr Jay – he is not a medical doctor. This is a common dishonest tactic. This dishonest tactic is : My resume’s bigger than yours. Your resume being bigger than mine suggests a possible reason why I might make a mistake, but that does not absolve you from having to point out the specific error or omission in facts or logic that I made. By your dishonest tactics, someone could look at your resume and say this – you are just a stupid student, Mr Tanner is just a lowly gym owner, Dr McGuff is an just an ER doctor, etc.

    There were NO facts or logic presented to the contrary when I presented Dr Jay’s thoughts previously. Where was he wrong? MAS brought the topic up and honestly wanted to be illuminated. McGuff, Tanner, Baye, Hutchins, and others of such ilk have skin in this game. They don’t wanna know the truth. Sad!

  31. Skyler Tanner MS

    Feb 11, 2019 — 12:55 pm

    Just added the MS to clarify: I’m a clinically trained exercise physiologist. That’s literally what my graduate education was. During our training, in addition to the standard progressions for cardiac rehab (Inpatient, Outpatient, etc.), the teaching of the utilization of strength training and HIIT were discussed. They’re even part of the ACSM Clinical Exercise Physiologist certification, because they’re part of the spectrum for effective rehabilitation.

    Now as far as the epidemiology, this is why I said “Get a VO2max test and check the ACSM tables” because if you’re after longevity, that’s the metric by which these studies are assessing projected mortality. HIIT, strength training, LISS aerobics are all tools. YMMV.

    And it’s a retrospective study, but it’s from the Cooper clinic (the father of aerobics in America) who demonstrated that lifting even once per week reduced heart attack, stroke, and death risk by 50% compared to not lifting at all. The sweet spot was 2-3 times per week and “BMI mediates the association of (resistance exercise) with total CVD events.”

    So if some low intensity aerobic activity helps to further mediate downward you BMI to the normal range, that would be prudent. Again, this is all part of an eco system of tools that may or may not be helpful for your situation.

  32. @All – This has been fun. An old school blogging thread in 2019! Not on Facebook or Twitter, but right here. It gives me hope that blogging isn’t dead.

  33. Just for the record.

    I spoke at length with a cardiologist with over 30 years of experience and whom graduated from Emory university. Is that resume enough? He stated resistance training could be problematic in that compliance of blood vessels would be affected adversely. He recommended letting the pulse pressures normalize between sets and at times even between reps. He was well aware of the deleterious effect on blood flow of the Valsalva maneuver.

    Everyone should be interested in how to limit the deleterious effects mentioned above. How can weight lifting be healthy? Anything in excess of normal body muscle mass is just bodybuilding dogma. That is not healthy either

  34. Ondřej Tureček

    Feb 12, 2019 — 11:49 pm

    Well, I spent about 4 intensive weeks studying just cardiology, this was of course on top of anatomy, biochemistry, physiology, pathology and all other medical subjects that took years. And those 4 weeks were packed with lectures, study, tests. One of the questions during my Internal medicine state exam was chronic heart failure. My teachers were prominent members of European cardiology boards, often recieved honors from president etc. My faculty is the 11th oldest medical organisation in the world.

    But you like “Dr.” Jay’s podcasts. Cool;-)
    And you even met a real doctor for 30 minutes. Excellent. Dunning-Kruger effect?
    But to keep it civil, I’d rather believe studies from 2018 than expert opinion from 1989. I am well aware doctors can be unaware of latest research. If RT is dangerous, medical organisations all around the world are fucking up massively by including it in recommendations. I’d love to see the research on blood vessel compliance being negatively affected by long term resistance training…

  35. Wow… I happened to reread this post, expecting the comment section to be long dead. I’m surprised indeed to find recent comments. So I will add to the discussion.

    I am curious about this statement by Skyler:

    “Only the most elite athletes are centrally limited (the heart muscle cannot keep up). The vast majority of us are limited by our ability to extract oxygen at the level of the working tissue.”

    I was just reading an article in Men’s Journal about the Fitness Age test developed by Ulrik Wisloff, a Norwegian exercise physiologist. In the story, Wisloff is credited with saying that it is the ability of the heart to deliver oxygen that is the limiting factor in how much oxygen your body can utilize, and that this is the most trainable aspect of VO2 max.

    Now I suppose that you might argue that his observation is only relevant to the performance of elite athletes. But if VO2 max is strongly correlated with longevity and reduced all cause mortality, and you are willing to assume that training for higher VO2 max might hypothetically confer some of the advantage that epidemiology has identified, then one might well decide to buy some insurance by training to improve VO2 max. And it seems the best way to do that is to train for the central adaptation, i.e., increase the ability of the heart to pump blood. And for that, traditional cardio done at a sufficiently high intensity seems more effective than resistance training. That is not to say that one cannot improve cardiovascular condition to some extent with resistance training of the HIT variety. But is it enough for everyone? I suppose that starts to become a value judgement.

    Post Script: I subsequently hit the google, and found another paper which provided a nice summary of the thinking (circa 2000) as to what limits oxygen utilization and running performance:

    “In the exercising human, maximal oxygen uptake (VO2max) is limited by the ability of the cardiorespiratory system to deliver oxygen to the exercising muscles. This is shown by three major lines of evidence: 1) when oxygen delivery is altered (by blood doping, hypoxia, or beta-blockade), VO2max changes accordingly; 2) the increase in VO2max with training results primarily from an increase in maximal cardiac output (not an increase in the a-v O2 difference); and 3) when a small muscle mass is overperfused during exercise, it has an extremely high capacity for consuming oxygen. Thus, O2 delivery, not skeletal muscle O2 extraction, is viewed as the primary limiting factor for VO2max in exercising humans. Metabolic adaptations in skeletal muscle are, however, critical for improving submaximal endurance performance. Endurance training causes an increase in mitochondrial enzyme activities, which improves performance by enhancing fat oxidation and decreasing lactic acid accumulation at a given VO2. VO2max is an important variable that sets the upper limit for endurance performance (an athlete cannot operate above 100% VO2max, for extended periods). Running economy and fractional utilization of VO2max also affect endurance performance. The speed at lactate threshold (LT) integrates all three of these variables and is the best physiological predictor of distance running performance.”

    (Limiting factors for maximum oxygen uptake and determinants of endurance performance. DR Bassett, E.T. Howley Med Sci Sports Exerc. 2000 Jan;32(1):70-84)

    So I suppose that your view of the relative importance of central versus peripheral adaptation will depend on whether you are training for athletic performance, or for the presumed health advantages of a high VO2 max.

  36. Ondřej Tureček

    Feb 13, 2019 — 8:05 am

    I think Martin Gibala would agree with you to a certain extent. Lawrence Neal (“a HITer”) did a podcast with him and if I remember correctly, it came up.

    Now, the question is, do scientists really consider such a specific protocol as HIT. With the exception of James Steele and colleagues, I don’t think so. The cardio-ST dichotomy is dissolving only slowly, and at best, they use some form of not-to-failure circuit training where you hop on another exercise after arbitrary time rather than reaching failure. That would skew the results in favor of HIIT, as I believe you need continous near maximal metabolic work to match HIIT cardiorespiratory benefits.

  37. Ondřej Tureček

    Feb 13, 2019 — 9:17 am

    Another issue with “broadening the portfolio” to HIT, HIIT, LISS…could be that the adaptations use different signalling pathways that sometimes go against each other.
    Can we say with certainty that even brisk walking for an hour daily doesn’t negatively affect hypertrophy? What about jogging, sprinting etc.?
    This is something even Brad Schoenfeld (certainly not a HIT guy, quite the opposite) pointed out in his Max Muscle Plan book. Regarding cardio, he recommended none, or 3-4 thirty to forty five minute cardio sessions of RPE 6-7, somewhat hard.

  38. @Ondřej – When I talk about approaching this like an investor and using the portfolio analogy, I’m not directly searching for the optimal balance. I’m looking at undervalued vs overvalued based on where I am at currently.

    So the allocation is directionally highlighting things I can benefit from in the short-term and taking a break from the areas that have received excessive work up to that point.

    I do the same thing with nutrition, especially fruits and veggies. Instead of eating a perfect balance of micronutrients across all varietals, I choose the food based on what I haven’t had recently.

    The elliptical was easy low-hanging fruit for me. Will it be in a few months. Probably not. I’ll need to adjust. Rebalance the portfolio -so to speak.

  39. OT

    WHERE is Dr Jay wrong?

  40. @MAS,

    Since OT made the inflammatory remark “Dunning-Krueger” effect and directed that comment at me, his intentions are clearly evident. He is here to only discredit a legitimate concern. His claim of civility is just that, a claim. Interestingly, he seems to have a connection with Mr. Tanner, another infamous anti-cardio HITer.

    No one has stated WHERE Dr Jay is wrong. Maybe OT and Skydog will get a “real” Dr, such as McGuff, to state where Dr Jay is wrong. I really like for this real Dr to tell us how resistance training increases preload to the heart. He seems to be the only Dr., real or fake, to believe this fairytale.

    It must be real frightening to be lecturing a crowd on HIT and fear someone in the crowd confronting the lecturer on the subject of cardio.

  41. @All,

    Just read the study “Associations of Resistance Exercise with Cardiovascular Disease Morbidity and Mortality.”

    Interestingly, Mr. Tanner conspicuously omitted this from his comments.

    “Compared with no RE, weekly RE frequencies of one, two, three times or total amount of 1-59 minutes were associated with approximately 40-70% decreased risk of total CVD events, independent of aerobic exercise (AE) (all p-values <0.05).”

    Notice, the remark independent of aerobic exercise. This study is no referendum on cardiovascular exercise. Just a reference to resistance training with many not included variables. Skydog omitted this to purposely mislead readers that resistance training is all that is necessary. This study is not proof as he would have you believe. Just HIT dogma meant to mislead the unwary. No one is saying to not strength train. More straw man arguments from HIT

  42. @Marc – Yeah, I’m going to continue with my cardio program.

    If HIT is right, then I just wasted my time.
    If HIT is wrong, then my heart will be potentially less healthy as I age.

    That is an easy choice for me. Put on a podcast and ride the elliptical for 20-30 minutes a few times a week. Let the smart people continue to hash it out and then peek in on the discussion every few years or so.

  43. Ondřej Tureček

    Feb 15, 2019 — 2:40 pm

    “Compared with no RE, weekly RE frequencies of one, two, three times or total amount of 1-59 minutes were associated with approximately 40-70% decreased risk of total CVD events, independent of aerobic exercise (AE) (all p-values <0.05).”

    I believe they just want to state that "cardio" wasn't confounding factor in the study – that it was purely and only RT that caused these benefits, even if no cardio was performed.

    I already quoted where Dr. Jay is wrong.

    “…the oxygen rich blood has a hard time getting into the contracting muscle as it (the muscle, that is) will SQUEEZE the blood vessels SHUT.

    “…the blood will have a harder time getting to where it is needed, which will increase heart rate in an attempt to FORCE blood into the muscles. Unfortunately, the net result is only a large increase in blood pressure and a LIMITED return of blood to the heart."

    These statements are incomplete or outright wrong. It is a dated mechanistic view of the whole process that ignores key role of other regulatory agents. Which is why I already posted this link:

    "For exercise to be sustained, it is essential that adequate blood flow be provided to skeletal muscle. The local vascular control mechanisms involved in regulating muscle perfusion during exercise include metabolic control, endothelium-mediated control, propagated responses, myogenic control, and the muscle pump. The primary determinant of muscle perfusion during sustained exercise is the metabolic rate of the muscle. Metabolites from contracting muscle diffuse to resistance arterioles and act directly to induce vasodilation, or indirectly to inhibit noradrenaline release from sympathetic nerve endings and oppose alpha-adrenoreceptor-mediated vasoconstriction. The vascular endothelium also releases vasodilator substances (e.g., prostacyclin and nitric oxide) that are prominent in establishing basal vascular tone, but these substances do not appear to contribute to the exercise hyperemia in muscle. Endothelial and smooth muscle cells may also be involved in propagating vasodilator signals along arterioles to parent and daughter vessels. Myogenic autoregulation does not appear to be involved in the exercise hyperemia in muscle, but the rhythmic propulsion of blood from skeletal muscle veins facilitates venous return to the heart and muscle perfusion. It appears that the primary determinants of sustained exercise hyperemia in skeletal muscle are metabolic vasodilation and increased vascular conductance via the muscle pump. Additionally, sympathetic neural control is important in regulating muscle blood flow during exercise."

    Now compare this to Dr. Jay's "explanation". Clearly most of what he says doesn't need to happen, as there are other pathways to achieve the desired effect without the hypothesised negative effects.

  44. If we take dr. Jay’s idea to it’s logical conclusion, muscle contraction and muscular tension is detrimental for humans. But running is great.


  45. Ondřej
    Feb 15, 2019 — 2:48 pm
    If we take dr. Jay’s idea to it’s logical conclusion, muscle contraction and muscular tension is detrimental for humans. But running is great.

    Logically flawed opinion to the extreme.

  46. OT,

    Since you have been rude as regards myself, I will respond accordingly. Your long winded post if full of your opinions. Your posted link is not applicable at all. You commonly take information out of context. You failed miserably to put out facts to prove Dr. Jay wrong. Quit kissing the seat of Hit’s trousers.

    It is common knowledge that over a certain percentage of muscular contraction that blood flow is impeded. Ever heard of blood flow restriction training?

    Arthur Jones once stated that ignorance can be dealt with, but stupidity – that is just genetics. Can’t deal with it. You are the latter.

  47. Ondřej Tureček

    Feb 15, 2019 — 10:39 pm

    BFR definition:

    The implementation of external pressure cuffs over the most proximal position of the limb extremities with the occlusion of venous outflow of blood distal to the occlusion site.

    They go out of their way to occlude venous otflow with external pressure cuffs. Clearly it is something they need to do. Otherwise, all RT would be BFR, wouldn’t it. Still, BFR is still considered safe for scientific study. They even believe this occlusion is benefitial.

    Again, we need to look at the long term outcome and cannot single out one process of many that happen simultaneously anyway.

    For example, fasted and fed cardio don’t differ much in fat loss as the fat burning advantage of one during exercise is a disadvantage during post exercise et vice versa.
    Many things are being studied for the first time, like recent Kevin Hall paper:
    “Ultra-processed diets cause excess calorie intake and weight gain: A one-month inpatient randomized controlled trial of ad libitum food intake”.
    One thing is clear, RT is gaining more and more prominent position in the guidelines all around the world. It has nothing to do with HIT and everything to do with scientific evidence.

  48. Ondřej Tureček

    Feb 15, 2019 — 10:48 pm

    Another example would be certain vitamins that within natural matrix of food help with free radical damage and in a pill form often cause it, which was originally a surprise to scientists. It’s because of where they act in the cascade.

  49. @All,

    Expand our thoughts!

    What would encourage eccentric left ventricular hypertrophy and compliant blood vessels as regards resistance training.

    Dr Jay states that rowing, such as the Concept 2 rower, is the very best for heart morphology. The C2 is a sitting deadlift with momentum usage.

  50. What if you don’t care about the very best? What’s a good safe starting exercise to build up upon? Easy on damaged joints but with good payoff?

  51. Ondřej Tureček

    Feb 17, 2019 — 8:26 am

    Why would you want eccentric left ventricular hypertrophy in the first place?

    “Clinical relevance
    Athlete’s heart is not dangerous for athletes (though if a nonathlete has symptoms of bradycardia, cardiomegaly, and cardiac hypertrophy, another illness may be present). Athlete’s heart is not the cause of sudden cardiac death during or shortly after a workout,[6] which mainly occurs due to hypertrophic cardiomyopathy, a genetic disorder.

    No treatment is required for people with athletic heart syndrome; it does not pose any physical threats to the athlete, and despite some theoretical concerns that the ventricular remodeling might conceivably predispose for serious arrhythmias,[19] no evidence has been found of any increased risk of long-term events.[20] Athletes should see a physician and receive a clearance to be sure their symptoms are due to athlete’s heart and not another heart disease, such as cardiomyopathy. If the athlete is uncomfortable with having athlete’s heart or if a differential diagnosis is difficult, deconditioning from exercise for a period of three months allows the heart to return to its regular size. However, one long-term study of elite-trained athletes found that dilation of the left ventricle was only partially reversible after a long period of deconditioning.[21] This deconditioning is often met with resistance to the accompanying lifestyle changes. The real risk attached to athlete’s heart is if athletes or nonathletes simply assume they have the condition, instead of making sure they do not have a life-threatening heart illness.[22]”

    Why would anyone train specifically for this adaptation?


    This above post gives the cardiovascular conditioning viewpoints of a preiminent expert on HIIT. He recommends a balanced fitness program of resistance training, HIIT, and traditional cardiovascular conditioning. He says ONLY traditional cardiovascular conditioning has been fully studied and the resultant benefits are well known. He does NOT recommend resistance training as the sole means to stay fit.

    Dr. McGuff and John Little misrepresented his views in their book BBS.


    Eccentric left ventricular hypertrophy is fully explained. The above is in agreement with Dr. Jay’s book, and is 180 degree opposed to Dr. McGuff, HIT, and SuperSlow exercise viewpoints on cardiovascular conditioning.

    Can HIT be this wrong on cardiovascular conditioning due to ignorance?

  54. A consensus has formed among the preiminent experts regarding cardiovascular conditioning. Dr. Gibala (HIIT), Dr. Kenneth Cooper (aerobics), Dr Kenneth Jay (cardiovascular conditioning), and science. They all seemingly are in agreement. Some misinformed persons say that they are all wrong – HIT – or worse – cardio doesn’t exist – McGuff.

    Kenneth Cooper M.D. current program:

    “His legs are strong and muscular, a testament to the 45,000 miles they’ve carried him — 37,000 during 40 years of running; the rest walked since 2004, the year he broke the tibial plateau in his right knee while skiing. (“I always liked downhill skiing and was quite good,” he says.)“

    “As he does most every weekday, he rides a stationary bike for 30 to 32 minutes, sometimes capping that off with a treadmill walk before heading to the weight machines. He does his usual circuit of 10 machines, counting aloud through 20 to 30 repetitions.“

    He weight trains 2-3 times weekly.


    Take that OT, Skydog, McGuff, Baye, and Hutchins.

  56. A 20 minute video of a “long term muscle magazine writer” with no relevant degree which would indicate his ability to interpret the research.

    The jury is still out, even Gibala admitted HIT could be a complete workout, stop trying to “win” and do what you like. I agree that “aerobic” training has more data behind it because that was the focus, but that’s changing now, especially given how little longevity benefit “cardio” gives for the huge amount of time invested, let’s talk again in a decade or two.

  57. Ondřej Tureček

    Feb 27, 2019 — 3:13 am

    Regarding telomeres, not a new concept, of course we dug deep on them during 2 years of biology at med school, still in my opinion very problematic to draw any conclusions regarding humans, they were nicely adressed in Skyler’s talk some time ago.

  58. @OT – “huge amount of time invested”

    I disagree. 20-40 minutes a few times a week is not that much. Yesterday it was cold and windy in Seattle, so I did 30 minutes indoors on an elliptical. I listened to a Spanish podcast. It is time I likely would have been sitting.

    I think what you are discounting in this debate is the consequences of being wrong. Both sides have the possibility of being wrong. If the cardio side is wrong, then we falsely invested time in something with limited payoff. In my example, even if my heart doesn’t benefit, my Spanish listening skills improve. However, if the HIT side is wrong, then the heart is potentially weaker.

    I’m still split on the topic. I don’t have high confidence on either side. I can also see that a consensus is not forming. The smart people on both sides will continue to be in disagreement.

    With all that said, to me the logical path is to engage in cardio periodically. Then do HIT if you can and cover both bases.

  59. @ Ondřej,

    I seems you have derogatory words for anyone who does not kiss the seat of HIT’s trousers.

    No jury is still out, as Dr. Gibala clearly recommended a varied training approach, for those with listening issues, that mean BOTH endurance activities & resistance training. Ditto Dr. Cooper, Ditto Dr. Jay. Those are the facts.

    I did not win anything, however cardio long ago won, as numerous science projects have proved beyond a doubt.

    There will be NO Arthur Jones and Nautilus to bring back the heyday of circuit weight training. Resistance training will never be as popular as cardiovascular conditioning. The reason being: CWT is a poor choice for cardiovascular conditioning.

    You bet on a losing horse.

  60. @OT,

    It is very obvious Skydog was not telling the truth when talking about aerobic activity as he said endurance activities would kill you. He contradicted himself in the same sentence . It appears he lied on purpose at the 47:00 minute mark.

    The truth:

    Clearly telomeres are lengthened by endurance activities. Someone should challenge him with questions at these tirades of his. Must be troublesome to do public speaking while lying to promote your misguided exercise views.

    He is your guy OT!

  61. @Salanth

  62. Most doctors and cardiologists make erroneous assumptions about resistance training and it’s effects on the heart and vascular system because they don’t know how it should be performed. I once argued with a cardiologist who believed it was harmful because of val salva’s maneuver. He did not realize that val salva’s maneuver can and should be avoided during exercise which eliminates the things he was concerned about.

    Also, more recently there was this:

    “Nonetheless, there is an emerging body of evidence showing that resistance exercise training (RET) appears to be as effective as AET in reducing risk of several chronic diseases. ”

    Mcleod JC, Stokes T and Phillips SM (2019) Resistance Exercise Training as a Primary Countermeasure to Age-Related Chronic Disease. Front. Physiol. 10:645. doi: 10.3389/fphys.2019.00645

  63. The blogger who says “most Doctors and Cardiologists make erroneous assumptions “ is the epitome of arrogance and foolishness.

    The Valsalva maneuver is a natural phenomenon of the body. Few may have the discipline to full avoid the VM during all out resistance training.

    Cardiovascular conditioning is actually well researched with known benefits to the body. This can not be said of resistance training benefit to the cardiovascular system.

    40 year old overweight wannabe rock singers are prime candidates for aerobics.

  64. Late to the party.

    Ondrej, yes the paper by Delp describes mechanisms of vasodilation during exercise. But these chemical mediators can’t overcome the laws of physics.

    During a sustained muscular contractions, the intramuscular pressure can be nearly 1000mmhg!!! (and that’s just in the upper extremity, the effect is necessarily larger in the legs), and no amount of chemical mediation can overcome that pressure differential.

    Any chemical mediation that occurs to facilitate flow has its effects during relaxation between contractions, and those won’t do much to help a HITer during a set:

    (though it does explain why venous pooling can make people light headed after a set).

    For most people, it’s irrelevant, because they are only “under tension” momentarily, but for HITers who use a continuous tension approach, the muscle is absolutely deprived substantially of oxygen during a sustained contraction.

    And this isn’t necessarily a bad thing – the research is staggering on the specific benefits of blood-flow restriction training (specifically with a restriction of arterial and not just venous flow). This effect is present during a constant-tension approach to training, and should be seen as a win, not a risk.

    Having said that, I was always struck by Dr. McGuff’s explanation of how deep contractions increase venous return to the heart. I can’t see how this is the case. For example at the start of a leg press, yes the leg muscles contract and “milk” their venous pool out and back to the heart, but after that, minimal new blood is entering the legs.

    In my mind, if a muscle is largely or completely occluded during sustained contraction, I struggle to see how return to the heart would be increased. If anything, cardiac output would be challenged by the increased peripheral resistance. I’ve always wanted to pick Doug’s brain about this to understand further…

    MAS, would love to hear if your thinking on cardio has continued to evolve. I wonder if the question “Is HIT enough” can be answered, individually, by the question “Do you get incredibly out of breath during HIT, and continue breathing heavily for up to 20 minutes afterwards.” If the answer to the second question is ‘yes,’ than obviously there is continued stimulus to the heart and mitochondria long after the exercise ends – due to the accumulation of lactate which must be metabolized (ultimately requiring O2), and CO2 which must be cleared.

    That’s not to say there’s no benefit to LISS – of course there must be adaptations to be had there. It’s just to say that “resistance training has no benefit to the cardiovascular system” is a ridiculous assertion, as you know.

    I’m also glad blogging is still alive, with all the old familiar faces from BBS …

  65. @Bryce – thanks for the detailed comment.

    I posted on my current thinking (July 2019) here:

    Short version: cardio helps me breathe deeper on HIT movements, s it benefits me.

  66. L R Gettman’s studies from years ago clearly show the increased cardiovascular conditioning occurring during running vs circuit weight training. Clearly, due to pressure gradient difference, occlusion, and reflexes such asthe Valsalva maneuver, heart preload is significantly decreased. The net effect reduces cardiovascular conditioning. That is why no serious endurance athlete uses resistance training as a sole methodology.

    Little, McGuff, Hutchins, Baye, Trentine, and such ilk all lied about cardiovascular conditioning. The research and empirical evidence has long been there.
    Furthermore, Darden and Jones put on blinders due to greed from Nautilus money.
    Only Bass and Sisco never prostituted themselves to the anti-cardio wagon.

  67. Hi, I hope you still read comments, as I have only just found the post re “Cardio Code”

    I have always argued, based on personal experience, that an aerobic base is a good thing and can only be developed with some long slow conditioning – aka the hated “cardio”. Apart from older texts, the best, simple, recent defence of this type of training is in the book “Tactical Barbell: Conditioning”.

    The books in this series are aimed at those who need multiple fitness qualities, such as strength and muscular endurance and reasonably high aerobic “fitness”. Unlike Cardio Code, this book is available at a reasonable price on Amazon (and elsewhere, if you look hard enough.) Although you can find it freely, it is one fitness book which is well worth paying for.

    The author doesn’t just rant, he presents a reasoned argument as to why an aerobic base is essential, even if you want to excel at more intense activities, and how high intensity only training can fail when you are pushed and have to keep going well past your normal short duration window.

  68. @Karoly – Thanks for adding the book recommendation.

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