When IS the best time to drink coffee? A new study offers some insight.

You there, with the coffee. Yes, you.

Are you going to bed in less than three hours? Or did you just wake up less than three hours ago?

If you answered, "yes" to either question, put the caffeine down and back away slowly.


Don't worry! You can pick it up again later (this is a judgment-free zone). But if you're reading this anywhere close to your bedtime or not too long after waking up, you may want to push pause on the caffeine intake just until you get to the end of this.

I've got news for you about when the best time to drink coffee isn't ... and is.

Big scarf, big coffee, big fun, right? That is, until bedtime. Photo by iStock.

For the first time ever, researchers studied caffeine's effects on our circadian clock, and the results are striking.

Your internal body clock is known as your circadian clock. This clock is present in every aspect of your body. As sleep physiologist Kenneth Wright told NPR, "[your circadian clock] is in your fat cells; it's in your muscle cells. It's in your liver, for example, as well as in your brain."

Doing something that offsets your circadian clock isn't just, like, setting your alarm for p.m. one night by mistake. Messing with your internal sense of time, especially over a prolonged period of time, can have a real negative impact on your health.

Yeah, you might even want to rethink the caffeinated drinks several hours before going to bed. Photo by iStock.

It turns out consuming caffeine at night doesn't just keep you awake. It can completely reset your circadian clock.

Wright and a team of researchers conducted a 49-day sleep study in which participants were given various treatments three hours before bedtime: exposure to bright or dim light and a double espresso or a placebo.

Then, the team checked the participants' saliva for melatonin, a hormone that controls sleep and wake cycles. Melatonin surges through your system at bedtime, helping you drift off to dream land.

For participants who drank the double espresso, their melatonin surge was delayed by an average of 40 minutes.

"Raise your hand if you've been personally victimized by late-night caffeine." Photo by iStock.

40 minutes may not sound like much, but it's enough of a shift in your circadian clock that it could make it difficult to get out of bed the next morning and could affect your entire day.

We all have days like this every now and then without doing too much damage, but if every day feels like this, it might be because you're consuming caffeine too close to bedtime. And a consistent lack of sleep can wreak havoc on your immune system and make you more susceptible to colds and viruses.

And hopping aboard the caffeine train first thing in the morning might not be great for your circadian clock either.

Sorry to be the bearer of even more unfortunate research, but ... yeah. Sorry.

I know it's pretty and smells like productivity, but timing is everything. Photo by iStock.

You see, it's all about cortisol. Cortisol gets a bad rap as the "stress hormone" but it's also the hormone that controls your circadian clock. When your body releases it, you feel awake. Your cortisol levels are highest early in the morning.

Buuuuuut caffeine interferes with cortisol production, and if you're guzzling the good stuff early in the morning, your body learns to produce less cortisol and comes to rely on caffeine.

Photo by iStock.

Heavy caffeine intake (think five to six coffees or around 15 Diet Cokes a day) can lead to nervousness, muscle tremors, and insomnia.

So when *is* the best time to drink your coffee?

Because, oh yes, my friends, here's the good news: There are some benefits to drinking caffeinated drinks (especially coffee) in moderation.

The best time to indulge your caffeine habit is mid-morning, when cortisol production is down and, odds are, you're hours away from hitting the sack.

Yes, this post was a long con to use this stock photo. What's good? Photo by iStock.

Mid-morning! The perfect time to enjoy a cup o' joe with a diverse group of multigenerational friends! Or alone while you hide from your co-workers.

Like we said, judgment-free zone.

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