Last week I realized that it might be more appropriate for me to have caffeine in the middle of my day, rather than at the beginning. Generally, when I wake up, I’m not struggling to stay awake. After several hours of wakefulness, my background level of sleep deprivation starts to take over and I start dozing off when my mind isn’t actively engaged. I tried this, and it did seem to work for me. I didn’t doze off driving back from work.
This weekend, I chanced upon a blog discussing the optimal time for caffeine intake:
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 and 9 AM 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 to use a drug when it is 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.
My meager understanding of coffee chemistry suggests that wakefulness promotion comes from caffeine blocking adenosine breakdown. I’m not really familiar with caffeine having an effect on cortisol production, but we’ll run with it. What I found most interesting about this is that it provides a more concrete explanation for progressive coffee tolerance. Your body sets a ceiling for cortisol production. You add more caffeine, but if it’s too much the body will down-regulate caffeine’s effect, thus making it weaker. So unless you’re doing a coffee fast, it’s probably best to have breakfast with high protein content after you wake up, and then have some coffee later.