Nice pun, Himura-sensei. Though I do question translating it as "low pressure" if the intention is to give enough ambiguity that it could apply to both the typhoon news and Ai-chan's state... unless there's a medical condition involving some sort of "low pressure" that I don't know of.
Hypotension (low blood pressure) can cause lightheadedness, fatigue and fainting if it's severe enough - since your brain isn't getting enough blood.
And in Japanese, it's 低血圧 - literally 'low blood pressure'.
Given amount of nosebleeds provided in Japan, that's not surprising.
Depending on how one is sensetive to difference of pressure, the one can forecast how severe there will be weather change. Oh, and no matter how long you are being knocked off by that state - when weather "releases", you feel like had a very good sleep.
Wait, hypotension makes one sensitive to changes in atmospheric pressure?
And assuming that Ai-chan doesn't suffer from any actual chronic illness that would give her constantly low blood pressure (which wouldn't really fit with practically any previous depiction of her), what would be the most probable causes for her current condition?
Probably just Gloomy Weather Lethargy. Don't know if it's related to low blood pressure or not, but it's proven that gloomy atmosphere can really make you feel listless.
Some cases DOES related to blood pressure. Speaking from personal experience.
There is even term "Meteosensevity". Rephrasing my case: usual hot bright summer day, previously I had enough sleep at night and didn't worked enough to fall from fatigue, and yet I feel myself heavy, especially head, and drowsing. Weather itself feels even hotter, slightly harder to breathe in unmoving air. Soon, in a hour or two, weather changes into heavy rain with strong winds. And in the moment when first drops reach ground, I feel energized regardless if I had a nap or coped that state.
