I've heard it phrased "Stress wrecks the body in strange ways." It is one of the best aphorisms I've been given. A physiologist friend told me this years ago when I was remarking how it seems like psychological stress seems to cause every subsystem of the body to freak out, yet there's no obvious connection between these things - why should the brain, which is evolutionarily "late", affect such deep subsystems?
This paper offers a clue into just such a connection. Immuno-psychiatry might be the next big thing.
This is also the reason why a lock-down against a virus is not always the best option for healthy people. A lock-down causes stress and this weakens the immune system.
Personally I think it is obvious why the connection between stress and 'subsystems' is there.
Stress puts the body into survival mode. Heavy breathing is an example. But when the stress holds on for too long it exhausts your body causing all kinds of trouble. The most extreme example is a burnout.
That is one aspect of a lockdown. But there are others and they are different for each person.
In the Netherlands it was estimated that a lockdown would save 150000 life years but would cost 650000. This takes into account a huge number of factors. For example health, but also job safety, happiness, and so on.
A lockdown causes stress for a lot of people. It seems you are not one of them.
Yes I'm not denying that it causes people stress. Just putting my thoughts in.
I think because I'm not stressed about it I'm definitely in a position of privilege. There are people who could not work during lockdowns - and I can completely understand why such people would be stressed. Not being able to make a living, and not knowing what's to come.
I think modern-day type of sustained, prolonged stress is just not something we've experienced much of prior to x,000 years ago, so there are simply no failure modes evolved yet.
A lot of the bad aspects of the stress response come from prolonged periods of not being able to do anything about it. If your village is raided, and you escape unharmed, you will be very stressed for a short period of time, but generally return to your baseline quickly after that. That's normal. That's what "stress" is for.
The modern world has the ability to stress you out over things you can do nothing about (or at least, not very directly and quickly), for long periods of time. Sit down and watch three hours a day for a week of whichever news channel pisses you off the most if you want to see. Some of you reading this already do that, so you may not even notice how pointlessly stressed that makes you because that's how you live. It also has a bunch of other humans who find it advantageous to stress you out that way and bend a lot of time and effort to the task of continually stressing you out, because they prefer that you not be able to carefully think about things but that you react less thoughtfully. You spend more money that way, among other effects.
Past life would spike the stress levels more often, sure, but it generally lacks the low-grade continual stress you can't do anything about. The exceptions that leap to mind (sieges! famine!) would generally be exactly that, exceptions. And in those cases... I'm sure the continual stress of sieges and famines wouldn't be good for them, either!
You don't actually have to be in conditions of siege or famine for them to be stressful. They merely have to be a threat. And what would a common person (i.e. peasant) have been able to do about that threat?
If your village is raided and you escape harm (quite the assumption), why would you generally return to "baseline"? What if the raiders took all your food and you can't feed your family? What if your family was murdered or raped? What if your village was destroyed and you're now a vagrant?
You are making the cognitive mistake of seeing the exceptions as the default, because the exceptions are what come to mind.
As I said, when constant persistent stress was occurring, I'm sure it wasn't any better for them than for us. But those were the exceptions. History writes about the famines and the sieges precisely because they're the interesting exceptions. Most people, most of the time, were not in a siege or a famine or under any particular threat from a neighbor.
Today, millions upon millions experience this mid-level persistent stress all the time, for decades. In the 21st century first world, it is the norm, rather than the exception. I don't think that's how it used to be. It especially didn't used to be that way when the danger of famine or siege is as low as it is now, making the stress response even more mal-adaptive.
I guess we just have different reads on history. I don't think it's a mistake to view hard times as the default for most of history in most places. They were of course not constant and there are accounts of exceptionally hard times. But I think the background level of hardship for the common person throughout the world >1000 years ago would probably drive most people currently living in the modern first-world to catatonia or suicide.
That's an oversimplification. The threat of war was not an everyday occurrence and really only became a thing when tribes evolved into nations and countries. Burnout is an example of the types of stress that are not like anything experienced in those thousands of years prior.
The threat of violence in the form of intra-tribal and inter-tribal violence was commonplace, even though nation states weren't a thing. I can't imagine that being less stressful than today where we have very close to zero chance of being murdered.
Hence the "predators and inclement weather". You can't imagine experiencing "burnout" with regards to incessant cold and rain preventing your tribe from effectively hunting/foraging? Or a pack of starving wolves harassing your camp at night for weeks?
Take this a step further and consider vaccine mandates.
However flawed or not the antivaxxer's reasoning, imagine the stress of having to choose between yours and your children's livelihood or being forced to inject a substance you consider risky into yours or your child's body.
The bulk of that fear comes from ignorance about how vaccines work, and there's enough reputable sources to get educated for free, learn how they have worked in the past, and make an informed decision.
It's more stressful to be sick two weeks and struggling to breathe because you got COVID, and I'm saying that as an asthmatic who is not scared of mild difficulty to breathe.
There is no sensible posture to rationalize antivaxing, but every country has a percent of the population who hesitates about vaccination, and a percent that not only refuses it, but stubbornly refuses to practice hygienic measures. This should be taken into account when designing future health programs.
I dont know if the brain should be considered so late. These subsystem would never have existed if not for the command center helping them to survive and evolve, even if you argue there was a soup of mono cellular machines for very very long.
This paper offers a clue into just such a connection. Immuno-psychiatry might be the next big thing.