I just watched a very interesting Ted talk by Christopher McDougall, author of "Born to Run". Here's the link to the video. (I've also read the book which is very interesting) His whole thing is about barefoot running, but the setup is what I found interesting.
His position is that our brains developed very quickly about 2 million years ago because of a concentrated calorie source, i.e. meat. The only problem is that bladed tools only started showing up about 200,000 years ago, so how did we hunt? He says that the physical advantage that humans have to all the other animals is that we can sweat which gives us endurance. We are not suited to stalk our prey and kill them with our bare hands. His theory is that humans hunted as a pack and literally ran their prey to death.
This theory seems to make sense to me on the surface. What are other theories about this and what (if any) implications does this have on the current thoughts on "chronic cardio"?
I know there have been some studies relating long distance running to heart disease, but I'm assuming those were done on people eating a SAD diet. Is it different for people eating real food?
Edit: I just read an abstract on this from the University of Arizona. Here is the link.
Endurance running is generally thought to be beneficial for gaining access to meat in hot environments, where hominins could have used pursuit hunting to run prey taxa into hyperthermia. We hypothesize that ER performance may have been reduced in Neandertals because they lived in cold climates.
There is big difference in hunting 2 times per week (probably different runner every hunt) and resting / low intensity for rest of the time and running 1+ hr 5+ times per week with 8+ hr jobs.
Persistance hunting only works in a specific environment. First, you must be in very good shape. You don't see the old guys doing the running. It's always some young guy, probably always one of the best runners of the tribe. He expends huge tons of energy. Without the tribe to help him later, this would be much more risky. If he loses track of the prey before completion, he will end up exhausted and without food and without much strength to obtain more. Therefore, I'd say this is a strategy for tribe members or desperate people only. And it only works in open hot environments where prey will overheat and where you have a decent chance of keeping track of the running prey. In large areas of the world, this hunting strategy would simply not work and if the ground were mushy or too steep, it still would not work. The hunter also exposes himself to higher predator attack like from lions. Also very dangerous. And it will only only work for prey that will not turn and attack a lone human.
Therefore, I would say this method was unlikely to be the most common hunting strategy. More likely, trapping, ambushing, and more sneaky methods were probably the norm.
Concentrated calorie source in the absence of bladed tools for a period of roughly 1.8 million years. My money is on marrow left in the bones in the remnants of kills of predatory animals, you just need a rock to smash a bone, no blade required. Just a theory, but no more implausible than McDougall's. I suppose marine life could be a sufficient calorie source as well.
As for sweating, spend any time simply sitting in a hot environment and the advantage makes itself clear, who is to say what the express purpose or purposes for which sweating developed were.
Heres a blogpost from Darwins Table on the subject: its worth a read(and some videos)