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>Less clear has been why physical activity affects the brain in the first place. I think the studies are looking at this backwards. Physical activity should p

>Less clear has been why physical activity affects the brain in the first place. 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. Then it probably makes a lot more sense, the brain is comprised of cells, just like muscles, that are either anabolic or catabolic. 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. 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. Lack of exercise put the cells in catabolic states and long term catabolic states lead to metabolic/energy production problems in the cells. So naturally if you consider lack of exercise as the natural state of humans, sure it will appear physical activity improve brain function.

mmmrtl 7y ago
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.
- throwaway_tech 7y ago
  >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.
  - tacon 7y ago
    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/ http://baye.com/building-muscle-losing-fat/ [1] https://www.amazon.com/Body-Science-Research-Strength-Training/dp/0071597174 https://www.amazon.com/Body-Science-Research-Strength-Traini... [2] https://www.youtube.com/watch?v=2PdJFbjWHEU https://www.youtube.com/watch?v=2PdJFbjWHEU
    - throwaway_tech 7y ago
      >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.
- deleted 7y ago
  [deleted]
- johnisgood 7y ago
  DNA works like a dimmer switch, not as an on-off switch though.
rosybox 7y ago
> 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.
- lordnacho 7y ago
  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.
  - dartdartdart1 7y ago
    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
  - lonelappde 7y ago
    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.
    - lordnacho 7y ago
      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.
chiefalchemist 7y ago
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.
JamesBarney 7y ago
> 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.
- throwaway_tech 7y ago
  >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 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).
bitwize 7y ago
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.
yahwrong 7y ago
> 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.

mmmrtl 7y ago

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.

throwaway_tech 7y ago
>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.
- tacon 7y ago
  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/ http://baye.com/building-muscle-losing-fat/ [1] https://www.amazon.com/Body-Science-Research-Strength-Training/dp/0071597174 https://www.amazon.com/Body-Science-Research-Strength-Traini... [2] https://www.youtube.com/watch?v=2PdJFbjWHEU https://www.youtube.com/watch?v=2PdJFbjWHEU
  - throwaway_tech 7y ago
    >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.
deleted 7y ago
[deleted]
johnisgood 7y ago
DNA works like a dimmer switch, not as an on-off switch though.

rosybox 7y ago

> 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.

lordnacho 7y ago
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.
- dartdartdart1 7y ago
  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
- lonelappde 7y ago
  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.
  - lordnacho 7y ago
    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.

chiefalchemist 7y ago

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.

JamesBarney 7y ago

> 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.

throwaway_tech 7y ago
>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 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).

bitwize 7y ago

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.

yahwrong 7y ago

> 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.