4. You can’t think.
Even missing one night of sleep can lead to some major cognition (thinking) issues. In a study published by Experimental Brain Research, a group of 18 men were given a task to complete. The first task was completed following a full night’s sleep. The next task was completed after skipping a night of sleep. Brain functions including memory, decision-making, reasoning, and problem-solving worsened, along with reaction time and alertness.