Physical activity levels were also within a standard deviation of one another (between western and h/g populations).
The brain evolved in similar conditions to modern man. I would argue current conditions are far better for the brain in terms of good nutrition and low disease.
The effect in the OP was not selected for, it is likely a serendipitous biochemical interaction. Repair enzymes from one part of they also effecting another.
As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners.
Within a standard deviation. Higher on average, but not much, and not significantly.
No where near enough to exert selection pressure.
PAL is 2.26 +- 0.48 for Hadza male and 1.81 +- 0.21 for Western Male. That's an average 25% difference in activity. I'm not a biologist but it seems like that could surely be significant.
Especially if the protein being talked about is generated by strenuous activity above some level. 25% total difference in activity could be a very large difference in activity above a threshold, since both groups are going to spend a lot of the day sitting around, sleeping or walking slowly.
Minute changes are actually a huge part of evolution. Evolution is much more about minute changes than it is about huge (standard-deviation-level) changes.
As far as exercise goes, maybe one standard deviation is enough to produce a brain effect. And maybe there is a lot of variation within modern populations, with many far enough below the average to have a significant effect.
I find it really hard to believe that any healthy Hunter/Gatherers sit around all day like so many moderns do.
That's an even more fascinating idea; so what other things could create the conditions for other repair systems to be activated. Maybe meditation, maybe different drugs, plants, ketosis etc...
And, of course, we know nutrients like Zinc and Vitamin C are essential for tissue repair via being essential for DNA replication.
That is speculation, and is unintuitive. Why would the brain "work hardest" when running? Why would modern humans not exert the same forces during sport? Why would humans, the top group-oriented predator, run from a lion?
The data linked above shows that observed Physical Activity Levels and caloric use are comparable to modern day. Stop inserting your own assumptions into the data.
I'd sure run from a lion if it was coming at me.
Ghost & The Darkness aside, lions generally don't hunt humans. But humans did spend a bunch of time pursuing game over long distances.
I recorded a video conversation with the pioneer of the lactate shuttle theory behind this mechanism which may interest you. https://www.youtube.com/watch?v=lThFQM503EU
[1] https://en.wikipedia.org/wiki/Lactate_shuttle_hypothesis
http://www.runnersworld.com/running-tips/how-to-achieve-a-ru...
http://cen.acs.org/articles/93/web/2015/10/Exploring-Molecul...
>The endogenous opioids seem likely to be assigned a significant role in the integrated hormonal and metabolic response to exercise. This article reviews the present evidence on exercise and the endogenous opioids, and examines their involvement in a number of widely disparate physiological processes
My memory is telling me that studies of exercise show the longest living are those that do anything from endurance to what the article below calls "mixed" sports. Powerlifting and high intensity training may offer some benefit, but it is not as much as endurance training.
What I found in a quick Google search to attempt to refresh my memory, is in agreement: http://well.blogs.nytimes.com/2012/12/19/live-as-long-as-an-...
Strength is highly correlated with reduced all cause mortality. Which direction the relationship goes is debatable, but being strong is pretty sweet in and of itself.
Anyways I've run marathons in the past, but I mostly do strength training now, actually mostly callisthenics. It's less dedication, gives me more of an adrenaline rush and easier to do than endurance training. I don't deny, though, that most of what I've read says that cardio is better if you just simply want to live as long as possible.
If you only watch TV or read while walking at an incline on the treadmill, it's easy to rack up the miles without inconveniencing yourself. I probably hit about 24 miles a week doing this.
reddit post with main study, also comments have HN posts about it and good critiques. interesting stuff.
I've seen the cardio U curve study before too but do not have it saved like I did the strength one.
It's also been proven that HIIT is much more beneficial for your system than LISS.
It might "seem" more beneficial to you, but likely is not more beneficial than the alternatives. However, something is definitely better than nothing, and do what works for you and makes you happy.
Source? What is your definition of 'better?' The context is in longevity, and my link offers some evidence against your statement, so I think you should provide some source for your claim that HIIT is consistent with living longer than LISS because that's not what I've seen published in the last 10 years.
I've competed now in three separate strength sports (powerlifting, strongman, olympic lifting). There isn't a single person on any competitive circuit that only lifts weights once every 8 days. You might be getting strong for you. You started in March, so you are on the ultra-beginner slope that means you can basically do any training in existence and make gains. That will steadily slow.
Regarding a definition of "strong", there are many, but the one most people in the strength industry agree on is:
* 2.5x bodyweight dead lift
* 2x bodyweight full squat
* 1.5x bodyweight bench
* 1x bodyweight standing strict overhead press
No offense to the one person you read, but hundreds of years of strength athletes are on the side of lifting weights multiple times per week.
I have actually read more than one "person". McGuff actually has some credibility, and cites many scholarly articles in his book. However his method is not aimed at competitive weightlifters, which suits me as I don't have hours to spend at the gym every week, or a desire to get huge. I do expect to be stronger than approximately 99% of my peers by the end of the year though, which in my book is a bit better than "strong for me".
Yes, but you said a workout every 8 days was optimum. I'm saying that's completely bad information. You don't have to compete to learn from people who compete.
You wouldn't learn an optimal golf swing from someone who only plays mini-golf at an arcade would you? No, you'd look at the true greats in the game.
Here are just a few people to read instead of McGuff, all of who have some actual strength credentials.
* Wendler
* Coan
* Rippetoe
* Dan John
* Pavel
* Abadjiev
* KilgoreHow much do people consider body shape when looking at those numbers?
The big criticisms of this kind of training would be:
1.) athleticism (he recommends machines, but free weights and calisthenics--replacing lat pulls with pull ups, muscle ups, etc is much better for athleticism)
2.) strength (he recommends machines, no momentum in movements, long recovery periods... this is basically how bodybuilders train to build the most muscle, but power lifters and athletes will optimize for maximum power, which includes momentum in their movements, and more endurance in their muscles)
3.) cardio/weight loss (you will burn more calories and build better cardio with higher volume, repitions)
4.) Injury (machines, low reps, high weights, all increase risk of injury)
Like what I've heard about automatic transmissions. Supposedly, some automatic transmissions do not lubricate themselves when coasting in neutral (the pump is driven engine-side), and for this reason you shouldn't regularly coast long distances at freeway speeds in neutral on an affected automatic. Why is it this way? Simply because it's easy to slave the pump off the engine-side, and at 65mph, you generally have your engine engaged! So why NOT?
Evolution is all about selective pressures, but equally important are the absence of those pressures.
The two work in concert because fast prey escapes line of sight and gets mixed up with each other easily, so human endurance becomes much less useful if you can't follow & wear down the appropriate target.
"Born to Run" is a fun summary/story about some of this science but there's more hard science out there too if you're interested.
If you have an elevated heart rate and exercising in the past that might mean going after food where you have to outwit, thus the brain needed to fuel/prepare for that.
Additionally, exercise could be fighting, you might also need elevated brain performance during a battle for survival.
It might also mean you are doing some work to get a system in place for food and providing that for others in the group.
Exercising is probably tied to survival, nourishment and providing. The brain probably has a reward system because it can expend more energy if there is more to be had soon.
Evolutionary speaking, those animals whose brains go into "extra learning mode" during exercise likely had a huge advantage over their peers whose brains didn't. Their brains picked up on skills related to hunting and survival and didn't waste energy building neural connections while they're sitting around not doing anything.
The fact is that none of this greatly influences reproductive fitness, so it is unlikely to be acted on by evolution.
The effect is likely just biochemical coincidence. Repair enzymes in one part of the body effecting another.
> The fact is that none of this greatly influences reproductive fitness, so it is unlikely to be acted on by evolution.
It absolutely does, in fact, it's probably a key influence of reproductive fitness in predatory species. The species that can gather more energy or more efficiently use that energy is going to out-grow their peers more each successive generation. And it's easy to see the relationship between more efficient learning and gathering more food.
A group of hunting animals that learn 10% faster during and after exercising than a control group would have a huge resource advantage because they increases both the pool of available prey and the likelihood of catching prey. Acquiring just 7% more calories (and translating that into 7% more offspring) would result in a population that is double the control group in 10 generations.
2. You are assuming fights exert the same effect as exercise.
3. You are assuming the selection pressure is great enough to effect allele frequency.
4. You are assuming humans fight alone.
5. You are assuming humans have extra knowledge to be gained in a split second of a fight.
6. You are assuming said extra knowledge would be overwhelmingly adaptive in a physical fight.
Breaking down adaptation is all about understanding your assumptions. It is easy to speculate, but it is hard measure evolution. However, given rigorous study we can measure adaptation mathematically and quantify it's impacts.
You need to see the connection of systems. Neuromuscular connection of basal ganglia: central part of brain - neural pathway - muscle - and then feeling of movement going back to the brain through hypothalamus and to other areas - from hypothalamus it goes to brain like a shotgun fire.
The more you do the same movement the more you fire up the same lines. In order to get faster and more effective movement you add additional channels for signal transport in neuronal connections {this happens through release of BDNF, which induces insertion of new channels, for faster transmission}. This molecule happen to influence formation of memory, survival of neurons and supress your desire to eat.
There has been an article from 1998 about reduced cathepsin, which happens to reduce this BDNF. (http://www.ncbi.nlm.nih.gov/pubmed/9514826)
Sooo, again, I dont know, but this seems a bit like a side effect of firing up those circuits, because more or less the same way works memory formation (long-term memory potentiation). I would guess here plays a role effect of neigborhood - niche influencing neurons sitting next to those active pathways.
BTW. Also movement should increase your bloodflow, waste created by neurons is now removed much faster, this should go the same for neurotrasmitters - molecules transmitting signal which just flow around and act as signal interference, thus removing part of interference and now you can fire clear signal.
Unless it's explicitly linked to surviving natural selection before reproduction, it's more likely that this finding is just a pointless by-product of another biomolecular pathway, even though it may have some discernible benefits.
It's like trying to puzzle out why there are nipples on male mammals - it usually devolves to some creative stories and hand waving.
That is, they're useful for the female and not particularly harmful for the male, so they live on.
It's also an instance of DRY (don't repeat yourself) "coding" in our DNA: basically males and females carry the same instructions, with a bunch of randomly interspersed if/else conditions that hinge on the presence of testosterone (coded for in the small Y chromosome)
With long term phenotypes like brain health, there probably isn't enough selective pressure to create or maintain this relationship.
Rather this result is likely the result of coincidence, and that coincidence was not deleterious enough to be removed by selection. Ex :
Exercise stimulates repair enzymes > Excess Repair Enzymes Filter Into Blood Stream > Excess Repair Enzymes Also Fix Brain Cells.
Both physical activity and brain-health improve survival and a small group of people whose brain became healtheir with physical activity survived at a faster rate than others.
Isn't it obvious ? I would assume exercise for early humans did not mean spending 30 minutes running for no reason. They probably spent that time running after a rabbit or running way with someone else's wife on his shoulder etc or tribes that kept well trained armies probably survived at a higher rate than tribes that relied on the Shaman to summon the dead.
Your question assumes that bodily health and brain health are separate and distinct things - as if we are mental beings that just happen to have bodies.
Perhaps we should read the headline as "exercise releases body healthy protein" ... I doubt we'd consider that an evolutionary paradox.
Probably these results should be considered ipso facto.
When you are not active, you don't need to be doing those things as much.
during all this the brain experiences a surge in blood levels, oxygen, metabolic exchanges happen faster and so your brain is more effective.
add into that, the body breaks down fats to power you, those fats have omega fatty acids that are released into the blood stream and go to the brain to provide nutrients.
this is why drinking coffee wakes you up.
what I really want is a pair of those leg pumps that assist the heart, so I can sit on my ass longer and code whilst getting the benefits of exercise on my brain :)
Maybe you should be asking the opposite question like why should evolution reward sedentary life? Human history involves daily exercise in some form that is more strenuous than a long walk and that's clearly connected to our general health and well-being both mentally and physically (why should these be separate to evolution?). What we're doing today is the exception, we shouldn't expect everything to work out as before.
I imagine we're in a temporary lull. Either modern society will collapse and we'll go back to farming or hunting and gathering, or we'll invent a exercise pill. There is effort in this direction:
http://qz.com/516757/scientists-are-working-on-an-exercise-p...
If you can live a sedentary lifestyle and still produce children, then evolution doesn't care. In fact, an indoors lifestyle is much more fit in the longterm than a life of hard labor.
Evolution isn't trying to create the Platonic Ideal of a human. It just is a thoughtless mechanism to efficiently reproduce DNA.
Hunter/gatherer humanity did not have the luxury of a sedentary lifestyle, so it did have a negative impact on your ability to produce children for a long time.
> In fact, an indoors lifestyle is much more fit in the longterm than a life of hard labor.
I think "hard labor" is a bit extreme, but even so, working a physically demanding job is still better for your overall health than a sedentary lifestyle of office job + sitting on the couch watching Netflix.
Again, evolution does not care. As long as you can survive to about 40 (long enough to raise children), it makes no difference.
Or maybe people will just learn to exercise regularly and stay healthy? That seems more likely than the collapse of society.
Maybe the extra energetic investment in brain health is only justified when there is an energetic surplus, and doing exercise correlates with having extra energy available? (As opposed to starving and thus needing to conserve energy.) But that doesn't actually make sense, since the extra metabolic expenditure of these processes can't possibly be all that high, and doesn't the brain use almost the same (huge) amount of resources whether it's at rest or very cognitively active?