I remember that first paper which found some sort of flush-out mechanism for the brain opening up during deep sleep. Do you have a link? I’ve been meaning to dig into that a bit more. I remember when I first saw it I thought it would be huge for understanding Alzheimers, but that was a while ago before I started seriously reading up on aging.
Anyway, environmental factors...
There’s a qualitative general pattern that various kinds of physiological stress—exposure to radiation or harsh chemicals (including smoking), chronic infection, malnutrition, sleep deprivation, etc—tend to accelerate aging. These are results which I generally don’t put too much faith in, at least individually—they’re too flashy, so there’s likely publication bias. That said, there is a plausible mechanism by which general physiological insults would accelerate aging. I’ll save discussion of that for a later post, but David Sinclair published a (general-audience) book earlier this year which discusses it quite a bit.
One important thing to note, more related to the OP: whatever the root causes of aging are, i.e. the things which are out-of-equilibrium on long timescales, those do need to be internal to the organism. We would have noticed centuries ago if changing the environment could forestall aging long-term. That does not mean these factors need to be inside particular cells; for instance, extracellular aggregation of certain long-lived proteins is one plausible root cause (e.g. elastin deposits as a cause of wrinkles). It is very likely that we are still missing connections in the causal graph, so there could easily be things building up that we’re not paying attention to yet. That said, there are relatively few things in the body which turn over on decade-plus timescales, so that severely limits the list of possible root causes.
Here is one link: https://www.sciencedaily.com/releases/2019/10/191031174650.htm . I was not able to find the one I was actually reading earlier (and apparently my poor sleep last night was not sufficient and I cannot remember how I found it....) but the link here seems to be referencing the study I was reading about.
BTW, when I mentioned “external” I was not thinking external to the organism (e.g., me) but rather external to the cells (or at least many of them) but within the confines of our body or organ.
I remember that first paper which found some sort of flush-out mechanism for the brain opening up during deep sleep. Do you have a link? I’ve been meaning to dig into that a bit more. I remember when I first saw it I thought it would be huge for understanding Alzheimers, but that was a while ago before I started seriously reading up on aging.
Anyway, environmental factors...
There’s a qualitative general pattern that various kinds of physiological stress—exposure to radiation or harsh chemicals (including smoking), chronic infection, malnutrition, sleep deprivation, etc—tend to accelerate aging. These are results which I generally don’t put too much faith in, at least individually—they’re too flashy, so there’s likely publication bias. That said, there is a plausible mechanism by which general physiological insults would accelerate aging. I’ll save discussion of that for a later post, but David Sinclair published a (general-audience) book earlier this year which discusses it quite a bit.
One important thing to note, more related to the OP: whatever the root causes of aging are, i.e. the things which are out-of-equilibrium on long timescales, those do need to be internal to the organism. We would have noticed centuries ago if changing the environment could forestall aging long-term. That does not mean these factors need to be inside particular cells; for instance, extracellular aggregation of certain long-lived proteins is one plausible root cause (e.g. elastin deposits as a cause of wrinkles). It is very likely that we are still missing connections in the causal graph, so there could easily be things building up that we’re not paying attention to yet. That said, there are relatively few things in the body which turn over on decade-plus timescales, so that severely limits the list of possible root causes.
Here is one link: https://www.sciencedaily.com/releases/2019/10/191031174650.htm . I was not able to find the one I was actually reading earlier (and apparently my poor sleep last night was not sufficient and I cannot remember how I found it....) but the link here seems to be referencing the study I was reading about.
BTW, when I mentioned “external” I was not thinking external to the organism (e.g., me) but rather external to the cells (or at least many of them) but within the confines of our body or organ.
[Just found it with a different seach. https://www.sciencenews.org/article/sleep-may-trigger-rhythmic-power-washing-brain ]
Aha, that study linked to the one I was thinking of: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880190/
Thanks!