HERE’S a word you shouldn’t try to get your head around if you haven’t had your morning coffee yet: chronopharmacology.
It is the “the study of the interaction of biological rhythms and drug action”, says Steven Miller, a neuroscience PhD student of Washington DC, and it applies significantly to the flat white or latte most people will consume sometime during the morning.
It also explains why you shouldn’t have consumed one at 8am.
“Drug tolerance is an important subject, especially in the case of caffeine since most of us overuse this drug,” Miller says on his blog.
“If you drink caffeine at a time when your cortisol concentration in the blood is at its peak, you probably should not be drinking it.”
This is because cortisol production is strongly related to your level of alertness and it just so happens that cortisol peaks for your 24-hour rhythm between 8am and 9am on average.
“Therefore, you are drinking caffeine at a time when you are already approaching your maximal level of alertness naturally. One of the key principles of pharmacology is use a drug when it is needed. Otherwise, we can develop tolerance to a drug administered at the same dose.”
Miller says the optimal time for caffeine is between 9.30am and 11.30am.
On average, he says, blood levels peak again between 12pm and 1pm, and between 5.30pm and 6.30pm.
Your coffee will therefore be the most effective if you enjoy it when your cortisol levels are dropping, but before the next spike.