Brief notes that while an hour of sleep loss might not seem like a lot, it’s certainly enough to negatively affect our energy levels and mood. Especially if you had any sleep debt going into this weekend, you’ll likely feel groggy and irritable heading into the coming week. “There’s no way around it,” he tells mbg. “You’re losing an hour, so you’re likely making a bad situation worse.”
This time change can also be an unwelcome surprise for our body’s circadian rhythm. This biological clock that sits in the brain’s hypothalamus dictates the timing of our sleep-wake cycle (when we feel tired and awake) and other key processes like appetite. To stay on track, it relies on cues from natural sunlight and darkness. While a small change in light-dark timing is no big deal, an hour shift can confuse our internal timekeeper and cause us to feel a little off. Breus equates it to the funny feeling we may get when traveling one time zone away.