<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>throwaway_tech</author><text>&amp;gt;It&amp;#x27;s a silly idea, but just a shower thought I&amp;#x27;ve been mulling over.&lt;p&gt;I can&amp;#x27;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&amp;#x2F;off.  So you may have the &amp;quot;selfless gene&amp;quot; as you call it, but by default it is turned off, so you don&amp;#x27;t warn your own of the predator, now same exact hypthetical, but it just so happens you ate something that introduced new viruses&amp;#x2F;bacteria into your microbiome, which happened to change your gene expression and turn on the selfless gene causing &amp;quot;you&amp;quot; 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?</text><parent_chain><item><author>rosybox</author><text>&amp;gt; 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.&lt;p&gt;I wonder if there&amp;#x27;s a selfless gene in humans that reduces the reproductive fitness&amp;#x2F;longevity of humans that aren&amp;#x27;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&amp;#x27;ve documented selfless genes that spur primates to alert predators to save close relations at their own personal expense.&lt;p&gt;Lack of activity might just be telling the body that we&amp;#x27;re useless and we need to exit in order to help others. It&amp;#x27;s a silly idea, but just a shower thought I&amp;#x27;ve been mulling over.</text></item><item><author>throwaway_tech</author><text>&amp;gt;Less clear has been why physical activity affects the brain in the first place.&lt;p&gt;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.&lt;p&gt;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.&lt;p&gt;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&amp;#x2F;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.</text></item></parent_chain></comment><story><title>Evolutionary history and why physical activity is important for brain health</title><url>https://www.scientificamerican.com/article/why-your-brain-needs-exercise/</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>xjay</author><text>Somewhat related: &amp;quot;How Immune Systems Can Influence Social Behavior&amp;quot; [1]&lt;p&gt;So yeah, maybe there&amp;#x27;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.&lt;p&gt;Maybe people who can&amp;#x27;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.&lt;p&gt;[1] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;psychcentral.com&amp;#x2F;blog&amp;#x2F;how-immune-systems-can-influence-social-behavior&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;psychcentral.com&amp;#x2F;blog&amp;#x2F;how-immune-systems-can-influen...&lt;/a&gt;</text><parent_chain><item><author>rosybox</author><text>&amp;gt; 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.&lt;p&gt;I wonder if there&amp;#x27;s a selfless gene in humans that reduces the reproductive fitness&amp;#x2F;longevity of humans that aren&amp;#x27;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&amp;#x27;ve documented selfless genes that spur primates to alert predators to save close relations at their own personal expense.&lt;p&gt;Lack of activity might just be telling the body that we&amp;#x27;re useless and we need to exit in order to help others. It&amp;#x27;s a silly idea, but just a shower thought I&amp;#x27;ve been mulling over.</text></item><item><author>throwaway_tech</author><text>&amp;gt;Less clear has been why physical activity affects the brain in the first place.&lt;p&gt;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.&lt;p&gt;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.&lt;p&gt;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&amp;#x2F;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.</text></item></parent_chain></comment><story><title>Evolutionary history and why physical activity is important for brain health</title><url>https://www.scientificamerican.com/article/why-your-brain-needs-exercise/</url></story>