Please Respond!


If you ask a body builder or an advocate of the primal lifestyle they will probably tell you that “chronic cardio” is a very bad thing. The body builders will tell you that steady state cardio will result in  very little fat loss and quite a lot of muscle loss. The primal advocates will tell you that endurance cardio is just plain bad for your heart, not to mention your hips, spine and every other joint in your body. Mark Sisson maintains that we are simply not designed to run for extended periods of time, however, over at the debate rages as to whether 100miles of training a week is enough, or too much.
So where does the truth lie? What is the cause of this disparity in opinion?

It is a truth universally acknowledged that a single man, oops I mean, people like doing what they are good at.

For decades scientists have been asking test subjects to exercise this way or that and reporting the result of the average person, usually in terms of VO2max,  a measure of a persons ability to utilise oxygen and an important determinant of their endurance capacity.  However, until this century, the papers completely skimmed over the fact that, in every one of these tests, there are some people who will respond to an extraordinary degree and others, about 10% depending on the definition of non-response, that barely respond at all, or may even become less fit. Some people respond to interval training, and some to endurance training. Some respond to neither and some to both. It’s not just for aerobic fitness that this disparity is observed, some people can gain muscle mass easily, while others are “hard gainers”, and some can build strength, and others can build neither.

Those known as “hard gainers” in the body building sphere, are termed “non-responders” in the scientific papers. Non-responders often become non-exercisers, and that’s bad.

However,  recently scientists have been asking if not responding to one type of fitness regime means you wont respond to any.  A study was published last year, where 21 men and women were trained for 3 weeks with either endurance or interval protocols. Then they were asked to sit on the couch for 3 month (detrain) and they swapped protocols for another 3 weeks of training. The authors tested the participants on three fitness indicators, including VO2peak . About 25% of the subjects didn’t improve their VO2peak with either regime, about 25% improved with both regimes, but signifcantly, about half the subjects improved with one type of exercise and not the other. In fact the greatest change in VO2peak was seen in a subject with a negative response to the interval training.

But that still leaves 25% who didn’t respond to either type of exercise. We think of cardio as being the best way to improve our cardio fitness, that’s why we call it “cardio”, but it turns out, you can also improve your VO2max with resistance training, such as lifting weights. Another bunch of scientists studied people who were trained with either endurance or resistance regimes, and then swapped over after 2 months of detraining. In this study, everyone, responded to either the resistance training, or the endurance training (and most people responded to both).


So it seems that there is a fitness regime for everyone, you just have to figure out what that is. None of this takes into account actual performance in a real race, the motivation of the individual to succeed at a sport, or the pleasure someone gets from their chosen fitness endeavours, but what’s the bet that the editorial office of Runners World is full of people who respond well to endurance training, and the over at the office is full of people who gain muscle easily?

For myself, I have now come to terms with the fact that I will never run 5k, but I enjoy interval training and lifting weights and can see (in a completely non-scientific way) the results of these activities.

What about you? Do you have  a favourite type of exercise? Do you think you respond to it, or is there some other motivation that keeps you interested?




4 thoughts on “Please Respond!

  1. Janet Plummer April 10, 2017 / 7:29 am

    I am so intrigued by this. I wish it was possible to have myself tested. I suspect I am a weak responder if not a non-responder to cardio. My sister-in-law, who is admittedly 10 years younger than me, recently started running again after taking a break for several years to have two kids and recover from a nasty ankle injury. She is, like me, slightly chubby and not particularly athletic looking. Although unlike me she has run marathons in her youth. Would that somehow have set her up for a lifetime of better fitness?
    But that aside, after several years of not running at all and gaining a little weight, she was recently able to run 10km again within about 6 weeks of resuming training. And given she has two small children, I don’t imagine she would have had heaps of time available for it. Had I been starting from scratch again I’m pretty sure it would take me at least 6 months. I was stunned (and quite envious) that she was able to do this so quickly. I have run 10km myself, several times so obviously I do respond, but it seems to take me so much longer and so much more effort to get there.
    Still, I do feel really good after running. And even if I’m not attaining those fitness levels as easily as others, surely all that exercise must be doing me some good on some level?


  2. chibipink April 12, 2017 / 9:32 am

    I have a sister-in-law like that. It’s very vexing to see how quickly some people respond, but it’s important not to compare yourself to them. The main thing is your own progress and your own PBs and find the exercise that suits you, while not forgetting all the good things you’re doing to your own body.


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