Subtitles section Play video Print subtitles Many of us wake up with one thing on our mind - COFFEE! Or at least, some form of caffeinated beverage to get your day started. But what if I told you you've been drinking your coffee incorrectly this entire time? We all have an internal biological clock called the circadian rhythm that regulates many processes throughout our body, including how sleepy we are through the day. And it's this clock that controls the release of a hormone called cortisol. Often referred to as the stress hormone because it's secreted in high levels during your body's fight or flight response. Cortisol also happens to be related to your level of alertness through the day. And it just so happens that between 8 and 9 AM cortisol levels peak. This means that your body has a natural mechanism to wake you up. And while you may think that caffeine can complement this mechanism, scientists have actually found that consuming coffee or energy drinks during peak cortisol production greatly diminishes the caffeine's effect. And builds up a greater tolerance to the drug in the long run. Overall, that means you get less of a buzz, and need even more to stay awake in the future. We break down caffeine addiction and tolerance in a previous video "Your Brain on Coffee", which you can check out here! For this reason, drinking coffee after your cortisol surge at 9AM is probably best. Scientists have found a few other times where cortisol peaks as well: between noon and 1pm, and 5:30 and 6:30pm. Which means your best drinking your coffee outside of these times. These cortisol spikes - and your circadian rhythm in general - are most strongly regulated by sunlight, meaning your sleep schedule doesn't come into play as strongly. So what if you wake up extremely early, or really late, should you drink coffee right away then? Well, scientists have actually found that cortisol levels do indeed increase about 50% right after you wake up, regardless of the time. Science says, wait at least an hour to get your cup of Joe, and your body will be optimally ready to go! Got a burning question you want answer? Ask it in the comment, or on Facebook and Twitter. And subscribe for more weekly science videos.