It's 7 a.m. and you're struggling to start your workday. Or it's 3 p.m. and your eyes are drooping, and so is your productivity. What do you do? If you're like millions of other people, you reach for a cup of coffee.

And for good reason, since coffee doesn't just kick-start your day by making you feel more alert and awake. (What entrepreneur doesn't need to hit the ground running?) Caffeine also causes your endocrine system to release glutamate, a neurotransmitter that increases your ability to learn and remember. (What entrepreneur doesn't want to keep improving their skills and knowledge?)

In a broader sense, a number of studies recapped by my Inc. colleague Geoffrey James show the health benefits of coffee. Coffee can reduce your risk of cancer up to 20 percent and your risk of Type 2 diabetes and Parkinson's disease by 30 percent.

So, yeah: coffee.

But not too much, or too consistently. Why?

First, a little background. The neurotransmitter adenosine builds up in your system throughout the day; that's one reason you get sleepy. Residual amounts of adenosine still remain in your brain when you wake up; that's one reason you might struggle to get going in the morning. 

That's where caffeine comes in. Caffeine blocks adenosine from binding to receptors in your brain. When adenosine can't bind, you feel, or keep feeling, alert and awake. (Drink enough coffee and you feel really awake.)

But not indefinitely. When your body recognizes that adenosine isn't binding, to paraphrase Jeff Goldblum, life finds a way and responds by creating more receptors. Research shows that within three days of consistent caffeine ingestion, the number of adenosine, nicotinic, and muscarinic (modulation of neuronal excitability) receptors is significantly increased.

More receptors means more coffee is needed to kick-start your day. More coffee is needed to keep you going. If you let the caffeine wear off, the adenosine "crash" is even bigger.

All of which means you start to really need that first cup of coffee. And you start to drink more and more coffee throughout the day, if only to avoid the inevitable caffeine-withdrawal headache.

And at some point, maintaining a constantly caffeinated state becomes your new normal. A 2019 study found that participants in a 20-day study increased their peak cycling power (a fine proxy for feeling alert and energetic) for the first 15 days of ingesting caffeine. The biggest boost came on the first day. After that, adenosine receptors started sprouting like wildflowers. Then the effect steadily diminished, until it reached pre-study levels.

Sound familiar? (Definitely does to me.)

Here's the good news. Research also shows that the changes in adenosine receptor levels typically reverse after a seven-day caffeine break. Think of it as a caffeine reset: By reducing your tolerance, you'll increase the boost you will feel when you start drinking coffee again. 

One way is to take a week off from coffee every month. That's what Ashley Richmond, the founder of Momentum Habits, does. She recommends taking the first week of the month off so it's easy to remember.

If that sounds too harsh, try the slower approach. That's how I overcame a 40-year, 100 or so ounces of diet soda per day habit. (Not coffee, but hey: Caffeine is caffeine.)

Either approach will help you reset your adenosine receptors so you can then maximize the effects of that first -- or afternoon -- cup of coffee.

Without needing to drink more and more to just achieve a steadily diminishing outcome.