Cycling in the South Bay

For a couple of decades now, biologists have been trying to patiently explain that all the things they taught us about lactate were, well, how do I say this diplomatically? Completely fucking wrong.

Wrong on the scale of “sun revolves around the earth.”

Wrong on the scale of “bleeding with leeches fights infection.”

Wrong on the scale of the “spontaneous generation of germs.”

Unlike religion, where once mistaken, always mistaken, science at least has the potential to reverse itself because it doesn’t claim infallibility but rather accuracy as far as we know now, subject to being disproved tomorrow.

And the “old school” mistaken view of lactate really was a temple of sorts for performance sports.

Remember how when you got serious about cycling and you learned that once your body runs out of the ability to produce energy aerobically, it kicks into anaerobic respiration by using the waste product lactic acid? And how it’s the lactic acid that causes the burn?

None of that is true. Your body has virtually no lactic acid in it ever because lactic acid cannot exist in the blood’s neutral ph, and is therefore instantaneously converted into lactate. And far from being a waste product, lactate is the fulcrum for all human metabolism: It is the inexorable product of glycolysis, it is an omnipresent and abundant fuel, it is produced anaerobically and aerobically, it is the brain’s preferred energy substance, it fuels other internal organs, it is created when exercising and when at rest, and it performs complex signaling and shuttling on an inter- and intra-cellular level that have earned it the moniker “lactome” for its pervasive effects and importance in human metabolism. Nor does lactate cause your muscles to burn. That’s caused by a molecule named “hydrogen.” You may have heard of it.

So the next time you hear someone talk about their lactic acid burn, just imagine them saying that the sun rises in the west. They are clueless.

Although this “news” is more than twenty years old, I was still living in the world of “lactic acid burn” until a couple of weeks ago, when Kristie sent me a review published in Cell Redox by G. A. Brooks, the scientist who began unraveling the secrets of lactate back in the 1980’s. Kristie likes to send me complex things that I can’t understand so that she can later explain it to me with simple words and gestures. Her pantomimes for “Cori cycle” and “oxidative phosphorylation” are Oscar-worthy, to say nothing of “peroxisome proliferator-activated receptor gamma coactivator 1-alpha.”

After reading Brooks’s review, along with some ancillary reading about lactate signaling and shuttling, not to mention looking up the phrase “cell redox,” I tried to figure out how or why any of this matters.

So what if everything I knew about lactic acid was wrong? Who cares? How does it affect my cycling?

Here’s why you should care, and you can thank Kristie for this handy-dandy explanation, which I have twisted up in my own words and likely made a mess of: Viewing lactate as a waste product used only in anaerobic respiration obscures its real function, one of which is the body’s single most important fuel and as the crucial fuel for virtually all cognition. Once you understand that lactate is pervasive as a fuel source, leaving aside its other signaling/shuttling functions, you have to ask why that matters? Why would the breakdown of glucose, not to mention exercise, result in the creation of an even more abundant and metabolically important fuel source?

Answer: Because humans were ALWAYS MOVING. Since hominids could not depend on Gu trees, Gatorade creeks, and Energy Chew bushes for instant, massive supplies of sugary energy, we evolved with an always-on, system-wide energy supply system that fueled muscles, organs, and especially the brain without needing a constant supply of glucose. This makes complete sense. Sugars like sucrose and fructose are only very recent additions to our food supply. In the past we obtained less energy with greater difficulty from relatively energy-poor sources.

In the past, food sugars were harder to come by and often large periods of time elapsed between meals. In the interim, the body still had to fuel itself, and most crucially the brain had to obtain a continual energy substrate regardless of whether or not there was any food in your belly at a particular moment. So we evolved a lactate-based fuel system that could create an energy source even as glucose was being broken down, and that would simultaneously serve as a the major precursor for the formation of glycogen. Glycogen is the molecule that allows the body to store glucose and then make it available when needed. All of this would take place whether at rest or exercising, aerobically and anaerobically, between cells and within individual cell mitochondria.

The point to all this is that humans were always on the go. They didn’t sit on the couch for ten hours, or sit in a car for five hours, or sit at a workstation for eight hours, or spend most of their waking time with their neck bent over their dumbphone with only intermittent activities loosely described as “exercising.” They did not adhere to the lunacy that we need, according to current U.S. national guidelines, a piddling 2.5 hours of high intensity, or 5 hours of moderate intensity exercise weekly.

Humans evolved moving much of their waking time and it wasn’t simply to lumber over to the fridge for some more alcohols. A more realistic activity guideline comporting with evolution and the proper functioning of our bodies would be something on the order of 5-7 hours of activity per day. That is certainly what the molecular biology of cell and brain fueling indicate.

Early hominids, and humans up until agriculture, walked an average of 10-20 miles every single day. Warrior Zulus ran more more than double that distance … daily. The human body evolved to move and to move a lot. Rather than motion being the exception to sedentary ass-spreading, sitting was the gross exception to a hominid’s waking hours. Doubt it? Look no further than our evolved sitting position: It’s a squat. You can hold it for a while, but certainly not for hours at a time.

Understanding lactate provides a crucial key to understanding cycling, and sports in general, which is this: Sports and exercise are dumb. They are modern inventions that turn human physiology on its head. Humans were made to move while waking, and be sedentary while asleep. Lactate’s real function is to support a fully-engaged, always-moving, mobile organism.

Anything less? Might as well be measuring lactic acid to feel the burn.

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