If your day doesn’t start without coffee, we get it—it’s a cultural mainstay and a near-lifelong habit for many, if not most, Australians. There’s nothing wrong with drinking a moderate amount of coffee, but there’s a good biological reason you may want to hold off a little longer than you’re used to before drinking your first cup.
A number of important biological processes, like alertness, metabolism, and muscle tone, are governed by your circadian rhythm—a 24-hour cycle that’s regulated by external and internal signals. In the morning, your body makes a lot of a hormone called cortisol. You may associate cortisol with stress, which it’s involved in, but another one of its important functions is helping you feel alert when you wake up. Cortisol levels typically peak between 8-9am, 12-1pm, and 5:30-6:30pm.
If you have your first cup of coffee when your natural cortisol levels are supposed to be at their highest, you are doing yourself a disservice. When your cortisol levels are up, your body is basically naturally caffeinating itself. If you feel like you don’t experience a natural jump in alertness when you wake up, even when you get enough sleep, your body may have become dependent on caffeine instead of cortisol.
Here’s how this happens. Caffeine actually hampers your body’s ability to produce cortisol, so as your body adjusts to getting a caffeine hit first thing in the morning, you will eventually produce less cortisol. The result is that your ability to feel peppy in the morning without a flat white is diminished. Second, drinking coffee when your cortisol level is high makes you build a faster and stronger tolerance to caffeine, reducing its effects.
If you want to get the most out of your coffee, you should delay drinking it until at least an hour after waking up. The best time to drink coffee it is between 10am and noon, and/or between 2 and 5pm.
Keep in mind that if you’ve been drinking coffee first thing in the morning for a long time, abruptly cutting out your morning cup can leave you with withdrawal symptoms like headaches and fatigue. Unless you have a serious amount of willpower, try tapering off slowly. Reduce the size of your cup gradually over the course of a few weeks. Slow, steady change is more likely to stick.
Lastly, remember that there’s not enough coffee in the world to counter the fatigue caused by sleep deprivation. Your first line of defense against daytime sluggishness should always be prioritizing your sleep.