Coffee mid morning
Ever wonder what the best time is to drink your coffee? You probably know it is not a good idea to drink part of your daily dose of caffeine in the afternoon. Especially for those who have problems sleeping. But, do you ever drink your coffee and feel like it just didn't work? I know I have that feeling sometimes. The explanation for this has to with a concept that I think is extremely interesting but rarely discussed: chronopharmacology.
IS 8 A.M. REALLY THE BEST TIME TO DRINK YOUR MORNING COFFEE?
Chronopharmacology can be defined as the study of the interaction of biological rhythms and drug action. One of the most important biological rhythms is your circadian clock. This endogenous 24-hour clock alters your physiology and behavior in variety of ways but it can also alter many properties of drugs including drug safety (pharmacovigilance), pharmacokinetics, drug efficacy, and perhaps even drug tolerance.
Drug tolerance is an important subject, especially in the case of caffeine since most of us overuse this drug. Therefore, if we are drinking 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 8 a.m. and 9 a.m. on average (Debono et al., 2009). 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 of a drug when it is needed (although I'm sure some scientists might argue that caffeine is always needed). Otherwise, we can develop tolerance to a drug administered at the same dose. In other words, the same cup of morning coffee will become less effective and this is probably why I need a shot of espresso in mine now.
Although your cortisol levels peak between 8 a.m. and 9 a.m., there are a few other times where--on average--blood levels peak again, like between noon and 1 p.m., and between 5:30 p.m. and 6:30 p.m. In the morning then, your coffee will probably be the most effective if you enjoy it between 9:30 a.m. and 11:30 a.m., when your cortisol levels are dropping before the next spike.