Reducing this all to wattage is a mistake. Radio waves penetrate, and impart their energy to different materials differently (i.e. 80W diffused vs 80W concentrated into specific structures/compounds/reactions). Being inside a strong alternating field for prolonged periods of time could also tip the bias in favor of one biochemical reaction over another, which may have other health consequences over the long term.
It was a worthwhile experiment, and the results aren't particularly surprising.
It's wrong to call it a mistake. It's not a mistake, it's a simplification. We understand that simplifications have limited explanatory power. That's the tradeoff--simplified models are easier to understand but less accurate. All models sacrifice some amount of accuracy.
It is a mistake, and it is an incredibly harmful one. Our technician class takes these low-rez undergraduate abstractions, & beats everyone over the head with them. Meanwhile, the average person can barely read, & is really in no position to argue--even when (correct) instinctual misgivings remain, and the technician was wrong to begin with!
Reducing the interaction between varying electromagnetic fields and the staggering dimensionality of health & living things to wattage is a mistake.
The only time I see people call a comment "harmful" on HN is when they're trying in vain to sound smart, trying to make big talk about how somebody's comment is stupid. I'm honestly just kind of tired of seeing these accusations of "this is a harmful misconception, that's a harmful way of explaining things," etc. It's pointlessly adversarial. It doesn't contribute to the discussion. It doesn't even make you sound smart.
It was used well when Knuth said "goto considered harmful", but that is a clickbait title for an article which advocates structured programming. The title may get people to read the article, but the actual article is the interesting part, the "goto considered harmful" title itself is reductive and just gets copied as a meme into HN comments.
"Goto Considered Harmful" was Dijkstra. Aside from that, you've spilled a lot of ink for a weak ad hominem.
Beating normies over the head with physics 101 explanations--ones that don't even begin to address the complexity of the subject at hand--to silence perfectly reasonable lines of questioning, is harmful. Exceedingly harmful.
The comment is about how "that's harmful" is a terrible comment. It's just such an awful, terrible type of comment that I've let some ad hominem in there.
> In terms of a possible thermal effect, we confirmed that exposure to RF-EMF in our system could not affect mouse body temperature as shown in Fig. S2. … There are few reports resulting in thermal effect or thermal damage to anesthetized rats after magnetic field (MF) or RF exposure, respectively.
power dissipation scales sublinearly in body mass, scales roughly as mass^.75
humans can dissipate 360W easily, though not necessarily comfortably.
that being said, the power usage is high. assuming uniform absorption, 4w/kg works out to roughly 200mw in the brain. here's a neuro paper that sets an optimistic limit at 40mw.
OTOH, we pump a lot more than that (relative to mass) into fly brains during imaging, although they're not expected to survive much longer than the imaging session. the laser in our lab is about 1w, after losses from the optics path and pulse picking, the power on the brain is usually around 20mw
I'm not sure they were testing with exposing the entire mouse to that intensity; they were specifically concerned with measuring the effects of that intensity of exposure on the cerebral cortex.
EDIT - "plausible speculation" replaced with clear quote from the article:
> ... Whole body exposure was at a SAR value of 4.0 W/kg for 5 h daily for 12 weeks for six randomly allocated mice. The other six mice received sham treatment for 12 weeks. The sham treated control groups were kept under the identical environmental conditions and treated the same circular pattern as the RF-exposed groups without RF-EMF exposure. The sham-treated and RF-exposed mice could move freely in their cage....
Thanks! I skimmed the article but didn't catch the whole body statement. I suppose it makes for a much easier experimental design than directing it just to the head.
According to the article thermal effects of the RF exposure were minimal to nil. There was evidence of damage to brain cells that was attributed to RF exposure. However mechanisms leading to damage within the cortical neurons aren't clear. The RF exposure induced intracellular responses to stress and damage to myelin sheaths, the latter was thought responsible for observed hyperactivity.
Only those parts of the body that happen to have good blood circulation or that are expected to need to sink a lot of heat have the structures necessary to couple significant EMF absorption into the main bloodstream "liquid cooling loop".
For example, human eyeballs are really bad at it.
Staring at a microwave that has been recklessly modified to run without door, or with a hole in the door, is most dangerous by turning the eye's inside which is similar to raw egg white into the cooked form: cooked egg white is unsuitable for a lens due to the very strong scattering from the coagulated proteins.
I'm sure other temperature sensitive parts exist with poor cooling, as they're not naturally expected to be able to get dangerously hot without the surrounding tissue heating it.
The lack of thermal effects they mentioned where whole body temperature; while hard to actually measure, I'd suggest thinking of the temperature of the blood in the arterial venous heart half when it comes to potential overtemperature. Yes, if the body as a whole has cooling issues, this blood that is about to enter the lungs (after coming from all around the body) is going to be overly hot.
But if the bottleneck is the lack of blood vessel density in e.g. the eyeball, this temperature issue won't show up when measuring in the heart.
In the study researchers were focusing on brain cells. The brain generally has a high rate of blood flow so by your reasoning brains cells would be less affected than low-flow regions like the eye. But measurements would have to be taken at a specific site to know for sure, in this case that would be in the intracranial space.
The RF was probably too low power to produce readily measurable effects on temperature in the brain. I imagine that it could be a difficult piece of data to collect. However, you're undoubtedly correct that whole body temperature wouldn't be informative in such a study.
Makes sense, keeping some distance from running microwave ovens is a good policy. After an oven has been in service for some time what are the odds seals become leaky, etc. Probably not a great risk but no harm in minimizing one's exposure.
I'm pretty sure the RF seal of a microwave oven door is a resonance seal that doesn't depend on conductive contacts for the shielding effect.
If the door mechanically seals properly like it's supposed to, all should be fine.
If the mechanics make it not be as flush as it used to, get rid of it or measure the RF power at it's operating frequency near it while it's running, to check whether it still properly seals the RF.
It was a worthwhile experiment, and the results aren't particularly surprising.