ELI5. Why is an increase in systolic pressure of 180 and up considered an emergency but not dangerous to us during exercise?
In: Biology
When your blood pressure rises during exercise, a bunch of other systems in your body also activate during exercise that make the temporary rise in blood pressure okay. The key part being it’s temporary. Short term spikes when your body expects it is generally okay.
When it’s high without exercise, your body doesn’t have those supporting systems activated, so the pressure to dangerous and puts more strain on your pulmonary system. Over time this can cause damage.
That blood pressure in isolation isn’t an emergency, it’s what it can be indicating or causing beneath the surface that’s the emergency. There are people walking around every day with SBP >180 that have no idea they have high blood pressure.
High blood pressure over years and years will damage blood vessels, the heart, kidneys, etc… This is what we call end-organ damage meaning that the blood pressure had injured an organ over time. There’s also something called hypertensive encephalopathy where you are confused because your blood pressure is high (essentially end organ damage to the brain). So if you show up in an ER with that blood pressure we might check your kidney function and a some basic heart tests but as long as you’re not exhibiting damage to an organ system, we’ll send you on your way with instructions to see your doctor.
Now, you can also have high blood pressure as the result of something else. Kidney stone? Broken bone? Yeah, your pressure will be up but pain control will fix that. Other more serious stuff, like a blood clot type of stroke can push up your pressure because your body is trying really hard to get blood flow to an area of the brain that isn’t getting good flow. Also, high blood pressure in pregnancy or right after can be a sign of eclampsia and should be aggressively treated or can cause death or disability.
If you put a pot of water on the stove and it starts to boil you wouldn’t be concerned. If you then realized you hadn’t yet turned the stove on you would be **very** concerned.
High blood pressure is not actually considered an emergency, except with specific exceptions. High blood pressure without signs of organ damage like chest pain, shortness of breath, or neurological changes is not a medical emergency. (And except in pregnancy/postpartum). If it’s chronic it certainly needs long term treatment with a primary care doctor, but doesn’t need emergency treatment in the vast majority of cases
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