Fudging numbers, taking colleagues’ credit, neglecting to bring forth important information: Temptations to cheat abound in our working lives. Where do these lapses come from? New research suggests its all in your head. Or, rather, the nutrients within it.

“Self-control varies over time within the same person,” management professor Christopher M. Barnes writes for Harvard Business Review. “Physiologically, self-control occurs largely in the pre-frontal cortex region of the human brain, and uses glucose as a fuel. The act of using self-control draws upon this fuel, which exhausts the fuel.”

As we’ve noted, you have only so much mental energy during a day. From what Barnes’s research suggests, the amount of sleep you get predicts the discipline your body can produce.

Why? Sleep deprivation depletes the glucose level in your pre-frontal cortex, Barnes writes. This has consequences for your decision-making: If you don’t get enough sleep, you leave your self-control engine running on empty. If you do get enough sleep, you restore that fuel base.

Interestingly, small differences in mattress time predict different behaviors. Barnes says that in one study he conducted, there was only a difference of 22 minutes in people who cheated versus those who did not. (Good argument for the snooze button, right?).

Organizations need to give sleep more respect

As well, other research has shown that people who slept for under six hours were more likely to cheat than those that got at least six–and Barnes reports that even natural variations in sleep, like if you range between 6.5 and 8.5 hours per night, are enough to predict different, possibly unethical behavior, the next day.