That’s because the longer you stay awake, your brain becomes less and less efficient at burning energy, Czeisler says.

Here’s why: One big function of sleep is to give your body time to replenish a molecule called adenosine triphosphate (ATP) in your cells. “Adenosine triphosphate is a molecule that researchers often call the energy currency for life,” he says. “It’s in all cells, and it’s where your energy to do things comes from.” As you burn more energy, you use up your stores of ATP. The less ATP you have available to you, the less efficient you are at burning energy. And the longer you stay awake, the longer you go without restoring and replenishing the ATP molecules.

Think of it this way: Your household appliances won’t work properly if you don’t have the right voltage coming in through your electrical sockets. The same thing happens when you try to use your brain with less power capability.

When your ability to burn fuel becomes degraded, that impacts different parts of your brain, Czeisler says, like the prefrontal cortex, for instance, which is the area responsible for judgment and self-control.

There are different stages of sleep that you go through each night. REM sleep is the stage of sleep when we integrate everything we learned from the day, Czeisler says. “In deep sleep [another sleep stage] you store memories,” he says, “and in REM sleep you seem to integrate those memories with other memories that you had previously learned. Insight seems to be an important element of what happens during REM sleep.” Meaning: Your brain makes sense of things while you sleep, which can be very helpful during a complicated fight!

By pausing your argument until you’ve both logged at least seven hours, you’re potentially giving yourself a subconscious way to solve whatever issue is at the heart of your fight in the first place. It’s totally possible that you’ll wake up the next day with a better understanding of the situation at hand, and a clearer picture of how to solve your own problems.

As BuzzFeed Life previously reported in the story 17 Small Things You Can Do For A Stronger Relationship:

“[Not getting enough sleep] makes people experience more negative emotions and react more strongly to bad things, which means that people might feel more annoyed or angry at their partner than they would if they weren’t tired,” Amie Gordon, Ph.D., a postdoctoral scholar in the Institute of Personality and Social Research at the University of California at Berkeley, told BuzzFeed Life in an email.

That is the opposite of helpful when it comes to successful conflict resolution.