Last month, I was in Tokyo, Japan to speak at Pioneers Asia, a tech event for entrepreneurs and investors. Even before I left on the 14-hour  flight, my brain was in overdrive: deciding what part of town to AirBnB in, figuring out the best way to get from the airport into the city, and deciphering the fare system for the myriad train and subway lines.

Not to mention preparing for my talk (yep, how to get a mental six-pack), strategizing how to connect with the other participants and finding a gym.

Most of the time, I daresay, we’re pretty lax about directing our thinking. But when we’ve got a lot on our plate or the pressure’s on, we don’t have the luxury of wasting mental energy – we need to optimize how we use every ounce of brainpower. Here are three distinctions to keep in mind:

Use your brain for processing, not storing. Dr. Sian Beilock, a psychologist and expert in performing under pressure, explains that working memory is like “a mental scratch pad. It allows you to hold information in mind and work with that information whether you’re trying to figure out the solution to a problem or taking a test or even trying to present what you’re going to say next, and we have a limited amount of it. We can only do and attend to so many things at once.”

So instead of using your brain to remember information – stuff to do, ideas to flesh out, problems to solve — capture it in writing (tapping it out digitally works but writing it down on paper is better). Bullet point the three things you want to say in that client conversation, map out a structure for the partnership. The more you’ve got going on, the more you should be writing down. You’ll free up your brain to synthesize and make connections, not be distracted with worry that things are falling through the cracks.

Use your brain for functional, not emotional, thinking. If you notice that you’re out of milk (and you make a note of it, right?) or you’re calculating the salary for the new CTO hire, that’s functional thinking. If, however, you think “What’s wrong with me, I was just at the store, why didn’t I get it then?” or “This isn’t fair, why is this guy getting paid more than I am?” those opinions and judgments have an emotional charge that can create a redundant and unproductive thought loop.

The first step is to simply start making the distinction between the two. Then, be vigilant: When you catch yourself in a redundant thought loop — like I did in Tokyo, when I found myself ruminating over a missed opportunity to connect with a fellow speaker that I admired — train yourself to interrupt the pattern. Grab a pen and pinpoint what’s really bothering you. Ask yourself: Am I investing mental energy or spending it? Is this going to lead to action?

Use your brain for digesting, not (just) ingesting. The amount of information we’re being inundated with at this point is ridiculous: thousands of emails, nonstop updates in our social media feeds, advertising everywhere. We need to turn off the avalanche and take time to synthesize. This means, says Shane Parrish at Farnam Street, “sifting through information, filtering the bunk and connecting it to a framework that you can use” so we’re not just walking around broadcasting other people’s opinions. Or, it can simply mean taking a moment to sit and let our mind wander.

Something to think about…