We are endurance runners (pub. November 17, 2024)

Race on Wednesday, November 13

Race on Sunday race, November 17

In the last entry I said that the crafty apes began to make stone tools, what were these tools used for by the first humans?

To have access to food that they didn't have before. An animal less than five feet tall in the steppe required something to give it an advantage. There was food; There is always carrion in the African steppes, but for our ancestors, there was a major problem, they were very small and in scavengers there are hierarchies, so when it was their turn there was practically nothing left, only the most difficult to obtain. But with their stone tools, they could break the bones and reach the marrow, the most nutritious food that was out of reach for other scavengers.

But would there be a way to get more?

Yes, leaving carrion and becoming hunters.

There is something that few people currently know, human beings are among the most physically resistant animals. Few animals can last as long doing non-stop physical activity as we can. Our body shows many adaptations for this.

To start, the musculoskeletal system: our lower limbs are much longer than our upper ones. This makes the muscle mass much heavier in the thighs and legs. This results in a longer stride and better balance for a firmer footprint. The bones, muscles, and tendons of the feet, on the one hand, distribute the impact of contact with the ground of each step very efficiently, on the other, they allow the foot to be propelled when it stops touching the ground.

When running, every time your foot hits the ground, your joints receive an impact of up to four times your body weight. For this reason, the surface area of ​​the joints has increased: thus, it distributes that impact over a larger surface area.

We have efficient lungs that can trap a large amount of oxygen so that a strong heart can transport it through the arteries to the muscles.

But muscles don't just require oxygen. They also need energy, of which there are two sources: glycogen and fats. Glycogen is stored in the liver and muscles. In endurance running, the muscles start with their glycogen and as this decreases, the liver has to release its glycogen into the blood. Finally, when there is no longer any glycogen, it begins to use fats.

Now, after an hour of running: the body is starting to take its toll. So something is required to reduce the perception of discomfort, something that frees you from stress, that allows you to distract yourself so as not to worry about the time, but that maintains your mood, your goal. This is where the endocannabinoid system comes in, neurotransmitters that fulfill this function. 

I used to smoke, a lot, I consumed up to two packs a day. One of the things that helped me quit smoking was running, I switched from nicotine to endocannabinoids.

But when running the body generates heat that has to be dissipated, the easiest way to dissipate this heat is through evaporation. Most mammals do it by panting. The tongue out with breathing is causing water to evaporate and with that, they dissipate heat. 

Human beings do it differently; we sweat The sweat glands, scattered throughout our body, produce an excretion that is practically salty water and when it evaporates, it dissipates heat throughout the body. But to make this more efficient, the hair coverage was reduced, which, being insulating, would affect evaporation. Another unique characteristic of humans; low hair coverage.

All of this makes us have great physical resistance.

But what use would it be for our ancestors to have so much physical resistance? 

Very easy, resistance hunting. For an animal less than 1.5 m tall, the only way it could capture large animals was by exhausting them, after chasing them for hours, and already at the point of collapse, falling on them in a group and using stone tools to kill them.

The first humans with these adaptations were Homo erectus, the most successful human species in the fossil record.

That's why I like to run at least one half-marathon a year. Like I did today.