If I were to drink an espresso at 5:30pm and then go for a 2h run, would the caffeine still affect my sleep at say 9:30pm? I understand that the half life of caffeine is around 4-6hours, so my question is, would this reduce after burning extra energy?
In: Biology
Caffeine doesn’t really give you any extra energy. It just inhibits the feeling of tiredness. How long it takes to disappear depends a lot on your metabolism. You don’t “burn it” or “use it up”. It gets filtered out of your blood by your liver and the broken-down leftover compounds are removed by your kidneys and pissed away in urine.
It’s not caffeine’s “half-life” as such. It isn’t radioactive. It is your liver’s and kidney’s capacity that determines how long it affects you.
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