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> I think the studies are looking at this backwards. Physical activity should probably be looked at as the natural state of humans and ask why lack of physical activity affects the brain.

I wonder if there's a selfless gene in humans that reduces the reproductive fitness/longevity of humans that aren't pulling their weight for the group. I could imagine that a gene that shortens the life of a member in a group could increase the survivability of the gene in the same way that we've documented selfless genes that spur primates to alert predators to save close relations at their own personal expense.

Lack of activity might just be telling the body that we're useless and we need to exit in order to help others. It's a silly idea, but just a shower thought I've been mulling over.

Not silly at all. You could even relate the suicide of lower status males to this kind of mechanic. Or the grandmother hypothesis about why women have a menopause.

Those seem to contradict. Lower status males would be striving for a chance reproduce, or having reproduced would need to work to elevate their offspring's status.

The idea is if you've lost the race, let your genes that are carried by the winners take your share of resources. That way your genes win anyway. The individual organism is a lottery ticket.

But both genders are prone to suicide, male especially, but that's more societal than genetic. If there is a comparison between equal situations between male and female, you got a point though. But most of the time, I'd say the median male suicide victim is in worse off situation than the median female victim, hollistically

>It's a silly idea, but just a shower thought I've been mulling over.

I can't answer your questions, but I can add some more food for thought to think about...consider the impact of ones microbiome in turning genes like this on/off. So you may have the "selfless gene" as you call it, but by default it is turned off, so you don't warn your own of the predator, now same exact hypthetical, but it just so happens you ate something that introduced new viruses/bacteria into your microbiome, which happened to change your gene expression and turn on the selfless gene causing "you" to warn your kind of the threat. Did you really warn them, or since the gene was only turned on by your particular microbiome at the time, are you just a host being controlled by trillions of bacteria and viruses?

Somewhat related: "How Immune Systems Can Influence Social Behavior" [1]

So yeah, maybe there's actually some subsystem that controls social behavior, to get rid of someone from the group, or out them to the group by having them unintentionally sabotage themselves, etc.

Maybe people who can't self-terminate are turned into some threat to society that would get them targeted, but their minds present it as some kind of game.

[1] https://psychcentral.com/blog/how-immune-systems-can-influen...

>> I wonder if there's a selfless gene in humans that reduces the reproductive fitness/longevity of humans that aren't pulling their weight for the group.

I think that’s where sexual selection kicks in: slackers are not liked and have less sexual partners than those who have something to show off. Reducing longevity is not necessary since people loose fertility long before death

Geriatrics compete with their offspring for resources. This is why most species don't have geriatrics. Humans have some special social structures that make geriatrics useful to breeding offspring.

Why do you consider anabolism/catabolism a binary classification? All living cells, and especially terminally differentiated ones like neurons will have a mixture of anabolic and catabolic metabolic processes taking place constantly, and there's not a straightforward reason to think that physical exercise is flipping some binary master switch that is "good" (by some arbitrary definition) for all cells.

>and there's not a straightforward reason to think that physical exercise is flipping some binary master switch that is "good" (by some arbitrary definition) for all cells.

Its not about a "master switch" turning on/off good/bad. The systems must work together to promote healthy metabolism of the cells/energy production. Catabolism and anabolism have separate metabolic pathways controlled by a distinct set of hormones.

Anabolism and catabolism must be regulated to avoid the two processes occurring simultaneously. Each process has its own set of hormones that switch these processes on and off. Anabolic hormones include growth hormone, testosterone and estrogen. Catabolic hormones include adrenaline, cortisol and glucagon.

More generally going back to the idea of muscle...you can't lift weights and gain muscle (i.e. grow) without also gaining fat. Growth can't be isolated to muscle cells, the entire body must be anabolic to grow, which means growth of fat cells too. Many people do not understand this basic point and will swear they put on muscle and lost body fat, it doesn't work that way growth is an all or nothing metabolic process. What can be done is you can add more muscle than fat, but you will be adding both. Or in the alternative you can't lose fat and not loss muscle, if you lose fat you are catabolic and you will loss muscle. Similarly it may be possible to loss more fat than muscle, but you will be losing both. Unless you have evidence to the contrary, in which case you would be sure to be an overnight billionaire, without any exogenous drugs/hormones, it is impossible to simultaneously grow muscle/lose fat.

I like your reference to catabolic/anabolic processes. Alas, you then made some incorrect claims.

>you can't lift weights and gain muscle (i.e. grow) without also gaining fat

Of course you can. I'd be happy to share my Google sheet of daily weight, losing about 0.06lb/day, and my BodPod measurements showing going from 28% to 20% body fat while gaining 2.5lbs of muscle mass. Sarcopenia would have taken another 0.5lbs of muscle in that one year period.

Drew Baye has several articles on losing fat while gaining muscle[0]. In the first few pages of Body by Science[1], Doug McGuff defines health as (1) the absence of disease and (2) a balance between anabolic and catabolic processes. Except McGuff makes it clear that almost the entire population in the developed world lives in a catabolic energy state, eating way more than we need, never flushing the stored glucose out of our muscles, the tank is always full[2]. But while that is happening, sarcopenia [catabolic] is removing muscle mass as we age.

[0] http://baye.com/building-muscle-losing-fat/

[1] https://www.amazon.com/Body-Science-Research-Strength-Traini...

[2] https://www.youtube.com/watch?v=2PdJFbjWHEU

>Of course you can. I'd be happy to share my Google sheet of daily weight, losing about 0.06lb/day, and my BodPod measurements showing going from 28% to 20% body fat while gaining 2.5lbs of muscle mass.

Sure your muscle/fat percentages changes over time. But you didn't simultaneously grow muscle and lose fat, that is not possible.

>Drew Baye has several articles on losing fat while gaining muscle

Again its done over time. There is never a point you are "losing fat while gaining muscle" simultaneously, you gain both or lose both...you can certainly gain more of one than the other, or lose more of one than the other.

Just as an example:

1. You lift putting yourself into a catabolic state, you will lose both fat and muscle in this state (your body if burning more fat than muscle...but its is breaking down both, it is not burning fat and growing muscle);

2. You refuel after your lifting with protein like Whey and some glucose to spike your insulin to force the protein into your muscles, you are now anabolic (your muscle cells and fat cells are both growing and storing this new fuel you consumed, and the protein is rebuilding the muscle, as a result your muscle growth slowly outpaces the fat cell storage and growth)

3. rise and repeat over time and yes you will lose fat and gain muscle (like you did), but the growth/losses never happened simultaneously. Your body was always either catabolic or anabolic...never both.

It is over time you achieve net loss of fat and gain in muscle, but physiologically it is impossible for those processes to occur at the same time.

This explanation/assertion is in sore need of citations.

https://www.rsc.org/Education/Teachers/Resources/cfb/metabol...

>Countless chemical reactions take place in cells and are responsible for all the actions of organisms. Together, these reactions make up an organism's metabolism.

>When a chemical reaction takes place energy is either taken in or released.

>Two types of metabolic reactions take place in the cell: 'building up' (anabolism) and 'breaking down' (catabolism). Anabolic reactions use up energy. Catabolic reactions give out energy. They are exergonic.

At the lowest level there are chemical reactions, is it not fair to say that chemical reactions are binary? Either releasing or taking in energy?

Within the cell the net of the chemical reactions is the metabolism which are either anabolic or catabolic.

There is no doubt there are many processes where one reaction triggers the other in an ongoing but the chemical reactions or metabolic reactions (net chemical reactions) are either anabolic or catabolic.

I agree that (1) is plausible and probably true. (2) might be true in your training regiment, and also may be nearly true in most circumstances, i.e. a good approximation.

Your theory of absolute anabolic vs. catabolic body state is absolutely bonkers. Biology does not work that way. Comprehend-able things are the simplified ones and every rule has exceptions.

>Your theory of absolute anabolic vs. catabolic body state is absolutely bonkers. Biology does not work that way.

That is exactly how physiology works (I think you may be mixing up chemical reactions with metabolic reactions). Its why when people talk about losing weight there is always a certain number of people who refer to the laws of thermodynamics (calories in/calories out), and generally that is true (calorie surplus = growth and calories deficient = break down).

Of course there are exceptions such as the body has hormones which cause certain exceptions like HGH which can trigger growth (anabolism) in caloric deficits or cortisol can cause breakdown (catabolism) in caloric surpluses.

Can you identify any metabolic pathway that is simultaneously both anabolic/catabolic?

https://www.ncbi.nlm.nih.gov/pubmed/10838463

I'll take my billion dollars in twenties please.

Anabolism and catabolism are constant and simultaneous processes, even on a cellular level.

Where does it say anything about people growing muscle when catabolic or losing fat when anabolic?

Just because the processes don't happen simltaniously, doesn't mean you can't gain more muscle than fat (or gain more fat than muscle) or lose more muscle than fate (or lose more fat then muscle), I never said the two were done at the same rate, just the body will gain simultaneously or lose simultaneously...but the body can't both gain and lose simultaneously.

Link a study showing simultaneous anabolism of muscle and catabolism of fat, or vice-versa...I'll wait.

You've moved the goalposts IMO, from the idea of being able to simultaneously gain muscle and lose fat with any particular diet and exercise regimen, to being able to simultaneously gain muscle and lose fat at any particular point in time. The former being what everyone means when they say they lost fat and gained muscle, the latter being a mostly useless concept.

But that study does implicitly contradict even the latter. The subjects were fed hypocalorically and had a net negative change in weight, yet gained lean body mass, implying at least some of the lean mass gain was fueled by metabolizing stored fatty tissue.

>You've moved the goalposts IMO...

I think when using the word "simultaneously" I fairly implied I am talking about metabolism (growth/breakdown) with respect to a point in time not over time.

>The former being what everyone means when they say they lost fat and gained muscle...

Again interpreting me fairly... I don't think anyone argues fat/muscle can not be gained or lost at varying rates resulting in net gains and net losses respectively over time.

>the latter being a mostly useless concept.

No more than understanding chemical reactions result in release or taking in energy. Sure for most people broad sweeping changes to diet and exercise will result in positive net changes to weight and MBI...but to athletes trying to gain muscle while not losing cardio, body builders cutting weight for a show, MMA/boxers making weight for a fight...these useless concepts come into play. Further, its not just world class athletes, to even the average joe going to the gym, these concepts are important to aid in maximizing gains, minimizing recovery times and improving overall performance when working out.

DNA works like a dimmer switch, not as an on-off switch though.

> A lack of physical exercise is going to put all cells, including brain cells, in a catabolic state the same as muscle atrophy will waste away muscles due to lack of physical activity.

Why is this? Using your brain cells won't lead to muscle atrophy.

From research we know physical activity is healthy for the brain, but there's no reason this should be the case from first principles. You can make the same argument in the other direction.

"The brain and body have existed in state with limited energy. So to maintain homeostasis when the muscles are used it puts the brain into a catabolic state to feed the new stronger muscles."

And if catabolism between muscles and the brain is linked then surely steroids will make people every smart by switching the entire body into anabolism from catabolism.

> Cells are cells, they are where energy is made, they are binary only existing in anabolic or catabolic states and never simultaneously existing in both states

This is 100% not true. All cells are simultaneously building stuff and tearing stuff down. Some hormones like insulin say "build more stuff, tear less down" and others like cortisol say "tear stuff down and stop building".

But the body can simultaneously build some stuff and tear other stuff down. Consider the transitions from different types of muscle fiber. From beefy body builder muscles to lean marathon running muscles. That will be tearing down a lot of proteins but building up a lot of mitochondria.

>Why is this? Using your brain cells won't lead to muscle atrophy.

Ever hear of marathon runners hitting the wall or bonking? That is the runner's body shutting down to preserve the remaining fuel to keep the braining running. That is the function of the brain is given priority over other organs and systems in the body when the brain/body are not fat adapted and glucose stores are running low.

>and if catabolism between muscles and the brain is linked then surely steroids will make people every smart by switching the entire body into anabolism from catabolism.

Certain muscle enhancing supplements due have recorded benefits to cognitive function, for example creatine (https://www.ncbi.nlm.nih.gov/pubmed/29704637). That said "steroid" is a broad brush stroke without a specific meaning as far as actual chemicals/hormones go. Moreover, as we know "steroids" in the general sense typically work by enlarging cells in the body, which yes may have helpful and desired effects with respect to muscle growth, but negative effects in other areas (enlarged heart) so unnatural growth does not equal unbridled benefit...rather anabolism (growth) is a normal and natural process that also includes catabolism (breakdown).

We're an "integrated" system. The body / brain contruct is something we invented. It's what human do. But we are not a body with a brain, or vice versa. We are body+brain. Period.

> So naturally if you consider lack of exercise as the natural state of humans, sure it will appear physical activity improve brain function.

I think not wanting to do more work or exert more energy than needed is the natural state of all of nature. Nothing does anything more than what requires the least amount of energy. However since humans are at least somewhat self aware they can 'determine' regular exercise is ultimately less annoying or less energy than being obese, depressed, and with likely more medical problems.

Animals developed brains so that they could move around without endangering themselves.

I remember a bit of research that came out of Seymour Papert's work. They took kids who were so severely disabled that they were immobile, and gave them a (physical) Logo Turtle to command, and to move around an obstacle course. The underdeveloped bits of their brain that governed locomotion started growing.