I find this quite an interesting topic, as I've come across quite a few people who do not drink coffee at all recently as they say it gives them heart palpitations, so they drink tea instead as it has "less caffeine".
I then point out to them that tea does have a decent amount of caffeine, and depending on how much they drink, they may be having as much caffeine as a cup of coffee and the responses so far have been generally of being really surprised, shocked and confusion. The last person I met would drink a lot of bubble tea, but couldn't drink coffee.
Which gets me to thinking how much of that palpitation is psychological (perhaps tried coffee as a child and experienced an uncomfortable caffeine kick etc) or if sensitive to something else to do with the coffee.
This was an interesting article on the spruce eats https://www.thespruceeats.com/caffeine-in-coffee-tea-cola-76…
It's American volumes. 7 ounce is approx 207ml
For those too lazy to read, here are the numbers…
Espresso, single shot: 29-100 mg (often around 75 mg)
Espresso, double shot (doppio): 58-185 mg (often around 150 mg)
Decaf espresso, single shot: about 8 mg
Decaf espresso, double shot (doppio): about 16 mg
Nespresso Espresso Capsules: 55-65 mg
Nespresso Lungo Capsules: 77-89 mg
Assam black tea (FTGFOP Grade): 86 mg
Bai mu dan/China white tea: 75 mg
Chinese ti kuan yin oolong: 37 mg
Darjeeling white tea: 56 mg
Indian green tea: 59 mg
Kenyan green tea: 58 mg
Ceylon black tea (OP Grade): 58 mg
From another search…Bubble tea - 100mg to 160mg
you are talking about psychosomatic manifestations.
my Dad says he is allergic to garlic.
he can eat it in food without being aware of its presence and is fine.
if you tell him that garlic is in the food that he is eating and he will have "symptoms" - nausea, stomach pains, mild heart palpitations.
just like young kids who don't want to eat vegetables. you "hide" the vegetables and they will eat whatever with out an issue.