The Best Time to Drink Coffee for Productivity (and When Not To)

A coffee-free morning is a form of betrayal. I love the taste and the ritual of coffee, of course. I also review coffee and coffee machines for a living. But caffeine is also, quite simply, a drug. It happens to be the drug I use to motivate myself in the morning.

And yet I know I should not feel strung out on caffeine at 10 am, the way I far too often do. I drink coffee in part to fuel productivity but instead often end up stretched thin. I've cut back significantly on my caffeine dose since my jittery coffee-pot days breaking stories at daily newspapers. I might instead spend ages making a single pinkies-up espresso cup. So why do I still often feel so hollow and shaky from caffeine?

It turns out that getting the most from coffee is not simply a matter of dose. It's also timing. And I'd been doing it wrong.

The best time to drink coffee always feels like five minutes before it's done brewing. But there's also such a thing as drinking your first cup too soon. I learned this after consulting a dietician and a neurologist about caffeine's effects on the brain.

Here's how to get the most productivity and pep out of your morning cup, and how to avoid anxiety and energy crashes.

Wait an Hour in the Morning to Drink Coffee

Caffeine is the original biohack and a shortcut to motivation on a gray morning. It is a stimulant that offers a potent chemical signal to your brain that the day has begun, even when you're not ready for it. By blocking a sleep chemical called adenosine, says Ellen Akkerman, a neurologist at the Virginia Spine Institute outside Washington, DC, “caffeine increases alertness and energy and decreases sleepiness and increases adrenaline.”

So it may seem a bit counterintuitive that you'd want to delay drinking your morning cup, when caffeine gets it off to such a rollicking start. The answer lies in a stress hormone called cortisol, part of the body's fight-or-flight response.

Caffeine causes a spike in cortisol, which helps give your body a surge of energy. But you know what else causes a big spike in cortisol? The mere act of waking up.

“Cortisol naturally rises when you wake, depending on the time that you wake,” says Julia Zumpano, a registered dietitian at Cleveland Clinic Center for Human Nutrition. "It typically peaks around 7 or 8 am and then gradually drops throughout the day.”

If you drink coffee while your natural cortisol levels are at their highest, Akkerman says, your cortisol levels—and therefore your anxiety and jitters—will spike a lot higher. Your energy levels will also crash down harder.

If you instead wait to brew coffee about an hour after your normal wake-up time, you can catch your cortisol levels on the downswing and prop them back up, leading to a more productive morning with fewer wild swings in energy and anxiety.

Maybe take your shower first. Make yourself pretty. Then drink some coffee.

But Also Maybe Don’t Wait an Hour. It Depends

But the above advice assumes you are waking up at a time that feels normal to you. Drinking coffee optimally is not as simple as setting your coffee machine to start brewing at 9 am. (Though the Oxo 12-Cup will totally do this for you.) Some people are natural early risers. Some are late risers. And so you have to pay attention to when your body actually seems to want to wake up.

“If you’re a late riser, that means your natural body alertness is a little bit later,” Akkerman says. Conversely, if you naturally wake up early, your body’s cortisol levels might peak will before 8 am. One way to track your natural circadian rhythms is by using fitness watches or smart rings to track your stress levels.

• Photograph: Simon Hill
• Photograph: Simon Hill
• Photograph: Simon Hill
• Photograph: Simon Hill

Oura

Ring 4

My editor, Kat Merck, is naturally an early riser, information she was able to back up with hard data from her Oura Ring 4 fitness tracker. Each day beginning after 6 am, her heart rate and other stress indicators start to spike. This happens even when she sleeps in on the weekend—all the way to, like, 7 am.

And so theoretically, 6:30 am is the worst time for her to drink coffee if she wants to avoid cortisol-fueled anxiety. It's also when she drinks coffee.

If you wake up earlier than your natural circadian rhythm, on the other hand, drinking coffee immediately might be the exact right thing to do. “If you have to wake up early for something—a job, whatever it is—but you're a late riser naturally, then it makes sense for you to use caffeine,” Akkerman says. “The sooner, the better.”

If you're a late riser but have to wake up at 6 am for work, you can ride the stimulant effect from coffee into the time of day your body is naturally most alert. This will prolong optimal cortisol levels, offering a bridge into the day.

Don’t Drink Coffee on an Empty Stomach

Much of the time, what people mistake for a caffeine crash is actually a sugar crash. Drinking coffee on an empty stomach might cause digestive upset, if you’re the sort who’s sensitive to acids. But it might also screw up your energy levels for the entire morning.

One of the main ways that caffeine gives you energy is by signaling your liver to release the glucose it still has stored from overnight. But by the time you wake up in the morning, that energy-rich sugar is probably in short supply.

"Unless you've been eating a really large dinner the night before, overnight your sugar stores are kind of depleted. Your lowest glucose, unless you're diabetic, usually happens in the morning,” Akkerman says. When cortisol spikes at peak alertness, your body then releases this last bit of glucose, which gives you an energy boost. Coffee causes much the same effect: more adrenaline, more glucose released from your liver.

“Right when your adrenaline hits, it kind of boosts the release of sugar stores from your liver, and then you get a crash,” Akkerman says. “And if you haven't eaten anything, you can get hypoglycemic, which can make you really shaky on top of everything else.”

The solution, says Akkerman, is to have a little complex carbohydrates and proteins. This might be anything from granola to peanut butter toast. The extra energy from the food will stop your body from crashing out mid-morning.

This, I learned from Akkerman, is the root of my mid-morning shakes. It wasn’t the caffeine. It was adrenaline and hypoglycemia. I’m not much of a breakfast person, but on Akkerman’s advice, I now eat a handful of peanuts each morning before my morning brew, to avoid an unexpected sugar crash.

Moderate Your Caffeine Dose

Some people process caffeine quickly and well. Some people don’t. Some people are also bigger than others. But the general rule of thumb from the US Food and Drug Administration is that 400 milligrams of caffeine per day is the highest dose that’s been demonstrated to be safe for most people.

This might amount to four 8-ounce mugs of drip coffee or three double shots of espresso. If you’re pregnant, the safe dose might be half this amount.

But people can also differ wildly in their ability to metabolize caffeine. “There's actually a genetic test you can take—it’s the CYP1A2 gene—that can tell you if you're a slow or fast metabolizer of caffeine,” says Zumpano. But for the most part, she says, the key lies in listening to your body. If you’re experiencing racing heartbeats or palpitations, you probably have had too much caffeine.

The same is true, she says, if you feel a hollow, heady combination of “wired but also tired” in the afternoon—a common feeling that is often the result of high adrenaline or cortisol-fueled stress levels combined with a post-lunch sugar crash.

“I'm a cardiac dietician,” Zumpano says. “So I see a ton of people with arrhythmia, tachycardia, A-fib—all of those things are way worsened by caffeine. Caffeine is one of the first thing I take people off of, and it really does regulate their heart rhythm.”

Stop Drinking Coffee by Late Afternoon

I know, I know. It’s civilized in France to take a little cup of coffee after dinner.

But Europeans also tend to be on a different circadian rhythm than Americans, Zumpano notes, with downtime in the afternoon. They’re also not drinking their coffee from a 10-ounce mug.

As a rule of thumb, say Akkerman and Zumpano, most people should stop drinking coffee by 3 pm, or maybe even at noon. This will depend on how much coffee you drink each day and how fast your body metabolizes caffeine. Even though many people can still sleep after consuming caffeine late in the day, Zumpano says, it often still quietly has effects on your sleep quality. Cortisol leaves your body only slowly.

“I have those patients who are like, ‘I can have caffeine anytime, and it doesn't affect my sleep,’ Zumpano says. “And I say, ‘Why don't we just try to get rid of it?’ And they're like, ‘My gosh, I'm sleeping so much better. I sleep through the night. I didn't know that was possible.’”

Don’t Switch to Tea Late in the Day

Akkerman, the neurologist, also cautions against switching to tea in the afternoon—a fairly common habit among those who don't want dramatic caffeine spikes in the afternoon.

Tea generally has less caffeine than coffee. On average, a cup of tea has half to three-quarters the amount of caffeine in a mug of drip. But the reason it feels gentler is not for lack of caffeine. Rather, tea releases caffeine much more slowly. Phenols in the tea slow the rate at which your body processes caffeine, leading to a much more stately and civilized feeling.

But because your body processes caffeine from tea more slowly, the caffeine can also linger longer in the body. Counterintuitively, drinking tea late in the day might actually disturb your sleep even more than coffee, depending on the amount of caffeine you’re taking in.

Don’t Vary Your Caffeine Intake too Much

If you mainline coffee all day and decide to go cold turkey, you'll feel the effects.

“If you're drinking a pot of coffee a day and all of a sudden you're going to stop, that's a significant difference,” says Zumpano, who cautions it's better to taper off of caffeine rather than stop suddenly. Caffeine withdrawal is a real thing, with common symptoms ranging from headaches to fatigue, irritability, and difficulty concentrating.

Symptoms of caffeine withdrawal can crop up as soon as a day after you stop drinking caffeine and are at their worst around two days after you stop.

This phenomenon can be quite relevant even in day-to-day life. If you’re a two-pot-a-day coffee drinker while at work but don’t even own a coffee maker at home? Your listlessness on weekends might be caffeine withdrawal. Either drink less at work, or maybe buy yourself a nice coffee maker. Might I suggest a nice Moccamaster?

• Photograph: Matthew Korfhage
• Courtesy of Moccamaster

Moccamaster

KBGV Select Coffee Maker

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