They are not incredibly dangerous, not be a long shot.

They can be dangerous to a very small subset of people with preexisting conditions and that's about it.

There often more caffeine in a standard coffee than half a litre of monster energy drink.

I'm guessing that every person is different when it comes to energy drink tolerance, or there might be some underlying conditions. Back when I used to drink energy drinks, I wouldn't really feel anything except for maybe feeling a bit more "energetic" but I'm not sure how much of that is placebo. Granted, I wouldn't drink 6-10 cans a day because I don't think they taste that good, and would only drink a can occasionally.

250ml: caffeine

Energy drinks: 80mg

Coffee: 100mg (80-120)

Cola: 25mg

Black tea: 12-20mg

Half a monster is 43mg caffeine. About as much as a Pepsi, or less than 3oz of Dunkin Donuts coffee (a small is 180mg at 10oz). I'm not at all saying you're lying about your experience, but what you are describing is an extreme caffeine sensitivity (or a reaction to something else).

I don't drink energy drinks anymore but to answer your question you build up tolerance.

I used to chug multiple of those on the way home from school and didn't feel a thing. I think we lose much resilience with age.

My boss drinks like 8 energy drinks a day. Idk how he isn't dead.

I have absolutely no idea how there are people that exist out there that can drink 6-10 of them a day without spontaneously combusting from tremor induced cellular friction.

A few years ago my doctor put me on beta blockers to try and manage my migraines. My blood pressure was always within healthy limits, usually around 110/70, on the beta blockers it dropped a little bit, but nothing drastic. My heart rate on the other hand?

Resting, it was 41-45 bmp, sitting and fidgeting it was 54-58bpm, and walking around it was 65-73. I'd have to really push hard at the gym to get it to 100 and it would drop back down so suddenly when I stopped I'd often get blue lips when doing cool down stretches.

My fingers and toes were always blue, I had chilblains in the middle of the summer.

When I asked my doctor if I should try Alpha Blockers because they don't effect your heart he said "just drink a can of redbull 3-4 times a day"

So that's what I did.

It wasn't until I changed doctors and she asked me about my tea and coffee habits that it fully dawned on me just how much caffeine I was having.

I completely forgot tea has caffeine, I'd have 5-8 cups a day, plus 3 no-doze pills, 2 red bulls and a ristretto on most work days. On weekends I'd have 3-4 teas, 2-3 red bulls, 2 coffees and a caffeine based pre-workout.

My resting heart rate during all this was about 58bpm....and I slept like a log.

Anyway, my new doctor was horrified and I'm on alpha blockers now. Still no migraines, I've had to cut out everything caffeinated except 3 cups of tea a day, my resting heart rate is 67bpm....but now I have orthostatic hypotension which kinda sucks. Not as bad as taking trucker crack just so my he would remember to beat. I also struggle with intermittent bouts of insomnia now, which is weird.