From micro to macro: changing the way we study the organism.
A New (Anti)Approach to Sports Physiology
The default object of study in human physiology, and therefore in health, nutrition, and training, is to try to discover the "instruction manual" of the human body.
To do so, we generally approach it through the reductionist method: analyzing how genes, molecules, or proteins work. This approach has been very successful in biomedicine when it comes to finding medications or vaccines for narrowly defined problems stemming from malfunctions in genes, molecules, or proteins.
However, this approach has not been successful in helping us understand much broader and more complex processes, such as staying lean, training more effectively, or living longer.
To be clear, I am not saying that we don’t know what we need to do to lose fat or improve strength; what I am saying is that this knowledge does not—and cannot—come from analyzing how a specific protein works. Instead, it comes from analyzing what happens at the macro level: when an entire person starts lifting weights, eating fewer calories, or sleeping more.
And I believe there is much to reflect on here. Despite the fact that the curricula in Sports Sciences, Nutrition, or Medicine programs continue to focus on learning biochemistry and physiology, the reality is that we will not make great progress in treating people through this path. Instead, we will advance by analyzing individuals' responses to different stimuli, habits, and treatments.
The mechanistic view of the human body, which dominates all these disciplines, continues to see the organism's behavior as an effect of its internal functioning. The parts of the body follow an instruction manual that we still do not fully understand, and this is what makes us capable of performing better or becoming ill.
Adaptation at Different Scales
However, we know that this is not the driving force of evolution. Species adapt to fulfill functions necessary for survival. These adaptations, when occurring across individuals (from parents to offspring), are called evolution.
For example, birds, insects, and bats all developed wings, even though each species comes from a different evolutionary lineage. This phenomenon is known as convergent evolution (post).
What does evolution have to do with physiology? Quite a lot, because, as you’ll see, evolution and adaptation are actually two components of the same process: the adaptation of a complex biological system to its environment (though I’ll have to delve into this in other posts to avoid digressing too much).
An individual attempts to adapt to the function required for survival at any given moment, and to achieve this, we engage in a series of physical, psychological, and behavioral compensations. A clear example of this is the fight-or-flight response.
When the environment frequently demands such adaptations, what we call long-term adaptation occurs. A good example of this is the increase in muscle mass when the environment repeatedly requires performing 30 pull-ups daily.
This adaptation is limited by the genetic possibilities of the organism. No matter how much the environment changes or how much you train, you won’t adapt to squatting 1000 kg because your genome doesn’t contain the necessary genes to develop muscles capable of supporting that load. Even if this were achieved through genetic doping, your bones or tendons would likely break.
But what would happen if we lived in a society where only those who could lift the most weight could reproduce, as occurs with some animals?
In that case, only the genes of the strongest individuals would be passed on, and subsequently, only the strongest of the strong, and so on for thousands of years. Over time, due to the random mutations that occur in every individual, the evolutionary lineage might eventually produce individuals with broader bones and stronger muscles. Evolution, therefore, represents another stage of the adaptive process.
What I want to emphasize today is that the driving force of this evolution is none other than changes in the environment, which modify the function that an individual’s organism needs to perform. This occurs at all scales of the adaptive process.
For example, what drives our organism is not having more mitochondrial mass, greater oxygen consumption, or stronger grip strength. No, what drives it is the goal of being able to run either faster or for a longer period of time.
And since the real objective is precisely that (running for a longer time), it doesn’t matter whether it achieves it through higher oxygen consumption, greater efficiency, or more or less reliance on specific substrates. These latter aspects are merely causes of the former.
The reality is that the organism adapts to fulfill the task in the most efficient way it can at any given moment. This depends on its current needs and the degree of stress affecting each of its physiological structures.
It is a self-organized adaptation, mediated by the interaction between the system and its environment, and therefore cannot be predicted. This is why training at high intensities will not necessarily improve your VO2 max, just as training at low intensities will not necessarily enhance fat oxidation.
It would be like thinking that eating brains will make your brain grow, or that consuming a lot of protein will automatically grow your muscles. That’s not how it works. The organism first assimilates nutrients and then distributes them according to its objectives.
It would be like thinking that eating brains will make your brain grow, or that consuming a lot of protein will automatically grow your muscles.
The same principle applies to training: the organism first strives to fulfill the function it needs in that moment, in whatever way possible, and then adapts to it in the best way it can. This process is not predictable.
21st Century Physiology
One of the major shifts in 21st-century biology is the reversal of the arrow of causality: moving from a perspective in which physiological processes determine the behavior of the organism, to one where physiological changes are a consequence of adaptation to a task, not its cause.
Or put another way: “physiology takes care of itself.”
Practically speaking, we don’t need to stress over understanding how every molecule in the body works to train effectively.
To begin with, we don’t even know how it all works. We only know a few things about what we can measure—or sometimes not even that. A year ago, I came across this tweet:
The problem I have with this isn’t that I learned it incorrectly or that that I didn’t even remember it. It’s that the mistake doesn’t matter at all for training properly.
In fact, often the opposite is true: trying to make our physiological models fit reality leads us to make numerous mistakes in training and health (examples include low-fat diets, proton pump inhibitors as “stomach protectors,” or taking medications to reduce fever and inflammation for every minor symptom).
When we delve into the realm of physiology, it is more likely that we are wrong than that we are right, because there is only one way to be right but countless ways to be wrong, and our knowledge is far from definitive.
One of the major shifts in 21st-century biology is the reversal of the arrow of causality: moving from a perspective in which physiological processes determine the behavior of the organism, to one where physiological changes are a consequence of adaptation to a task, not its cause.
In training, attempting to force our physiological threshold models to fit reality led us to believe in the existence of a power threshold that significantly altered adaptations above or below it, or that producing lactate was detrimental to improving aerobic fitness.
I’ve realized that, much like with data, studying physiological processes provides a sense of comfort because it makes us believe we are working with certainties. (I wrote an article about this)
And the belief that we can have certainty about how to train is like nectar for our Paleolithic brains, thirsty for security and loathing uncertainty.
When we delve into the realm of physiology, it is more likely that we are wrong than that we are right, because there is only one way to be right but countless ways to be wrong, and our knowledge is far from definitive.
I suppose that’s why so many trainers focus on repeatedly studying biochemical processes, even though in their field this will have almost no impact on how they actually train.
In fact, after understanding this, I’ve come to see that the concepts shaping my understanding of the organism—like the differentiation between metabolic pathways for energy production—are much less important than I once thought. Everything exists on a continuum between maximal strength or power (running very fast) and endurance (running for a long time). The theory I had to memorize during my studies was only holding me back!
This is what motivated me to write this article. How is it possible that we could be wrong, and yet this doesn’t change the advice we should give athletes or individuals about how to train or act? In fact, how is it possible that knowing nothing about theory could even be an advantage?
What should we do, then?
From now on, my perspective is to move away from reductionist physiological explanations, because whay they do is fragment what cannot be fragmented.
What’s important is to focus on the macro: understanding how we adapt to stimuli, how to create the stimuli we are aiming for, how to organize stimuli to reach our goals, and how to measure whether the stimuli align with the organism’s capacity to adapt and whether they are achieving the desired outcome.
In short, as coaches, we must focus on the macro: stimuli, habits, routines, and environment. Of course, we need a strong physiological foundation, but we should not base our decisions on it. “Physiology takes care of itself.”
Or, as I said: “Function makes functioning.” We need to plan with a focus on the function we are requiring the organism to fulfill, and less on how it works.
Because, ultimately, and as I also say in my book: “Nature does not need us to understand it in order to function properly.”
Our ancestors didn’t need to know physiology to give their bodies exactly what we now know they require: lots of low-intensity movement with occasional bursts of strength, periodic exposure to cold and heat, intermittent fasting, circadian rhythm alignment, and so on.
They didn’t know it, and they didn’t need to, because the body evolved to fulfill that function (surviving in a Paleolithic environment) and not the other way around.
The extinction of that natural habitat and its impact on our health will be a topic for another discussion. :)
PS2:
Forgive me, I had to paint it. We can fool ourselves as much as we want, but at the end of the day, the best predictor of health is functional capacity and adaptability. In fact, health is adaptability in complex systems. So stop focusing on changes in isolated parameters and start thinking about the synergy between them—about the FUNCTION you achieve.