If you've ever wondered why you're up all night after one coffee but your friend can drink a double espresso after dinner and fall asleep with no issue, science might just have the answer.
A physician found a person's response to caffeine is likely determined by two main genetic factors: whether their liver can metabolise caffeine quickly or slowly, and whether they carry a genetic variation that makes their central nervous system more sensitive to it.
Dr J Langer said coffee drinkers fall into one of three major groups: high, regular and low caffeine sensitivity.
Willie B. Thomas via Getty Images
Advertisement