When the “fall back” time change occurs, you actually gain an hour of sleep as Daylight Saving Time (DST) ends and clocks are set back. Despite this extra hour, many people still feel tired, unsettled, or experience a few days of grogginess. This disruption occurs because the change affects the body’s internal timing system, even though the external clock seems favorable.
The Mechanics of the Clock Change
The “fall back” transition happens at 2:00 a.m. local time on the designated Sunday, when the clock is moved backward to 1:00 a.m. This means the day of the time change contains 25 hours, effectively repeating the hour between 1:00 a.m. and 2:00 a.m. If a person maintains their usual bedtime and wake-up time, they will have spent an extra hour asleep. This objective gain of one hour differentiates the fall transition from the spring one, where an hour is lost.
How Gaining an Hour Affects Your Circadian Rhythm
The primary reason for feeling unsettled despite the extra hour is the disruption to the body’s internal timekeeper, the circadian rhythm. This roughly 24-hour cycle regulates numerous physiological processes, including when you feel sleepy and alert. It is largely controlled by the suprachiasmatic nucleus (SCN). The SCN operates independently of the external clock and relies heavily on environmental cues, particularly light, to stay synchronized.
When the clock moves back an hour, your wake-up time is suddenly one hour earlier relative to your internal body clock’s schedule. Your body may still be producing melatonin, the hormone that promotes sleep, at this new, earlier wake-up time, which can lead to grogginess or difficulty waking up. This misalignment between the social clock and the biological clock creates a temporary state similar to “mini social jet lag.” The body’s systems function best when synchronized, and even a one-hour shift can cause them to work less efficiently until they adjust.
Strategies for a Smooth Transition
To help minimize the feeling of being “out of sync,” prepare the body for the change in the days leading up to the transition. Gradually shifting your sleep and wake times by 15 to 20 minutes later each day for a few days helps ease your internal clock into the new schedule. This prevents the abrupt, one-hour shock to your system.
Managing light exposure is an effective strategy because light is the main signal for resetting the circadian rhythm. Seek out bright natural light first thing in the morning on the day of and the days following the change to help shift your body clock faster.
Conversely, limit your exposure to bright light, especially from electronic screens, in the hour before your new, later bedtime. Maintaining a consistent sleep schedule, even on weekends, is the most effective way to manage the adjustment and support overall sleep health.