When Daylight Savings Time (DST) ends in October, we get a whole extra hour to sleep in that weekend, right?


Maybe not.


We might be gaining an extra hour by the clock on the bedside table, but our body’s clock may be losing time. Sleep deprivation is associated more with the advent of Daylight Savings Time, but according to a review in the journal Sleep Medicine Reviews by Dr. Yvonne Harrison, a senior lecturer at Liverpool John Moores University in England, even a little one-hour shift in our sleep cycle can affect sleep up to a week after DST ends. In other words, it doesn’t matter so much whether we’re springing forward or falling back. What matters is the disruption to our sleep cycles.


Many of us aren’t able to enjoy the “extra” hour of sleep that comes with the end of DST. For the week after the time change takes effect, we tend to wake up earlier and have more difficulty falling asleep. When we do sleep, we are more likely to wake up during the night. If we are among those who get under 7.5 hours of sleep per night or are early risers, we have an even harder time adjusting to the new sleep schedule. 1


Sleep is important to our circadian rhythms—our inner clock that governs the physical, mental, and behavioral changes that we normally experience during a 24-hour time frame. The daily cycle of night and day—light and darkness—keeps those rhythms on track. When this cycle is disrupted, as when DST ends or begins, it affects those circadian rhythms. This could lead to everything from grogginess that affects our concentration–and thus things like jobs and school that require full concentration–to negative changes in our general health and mood.


How do you beat the clock? Maintaining a regular exercise and sleep schedule may help reset your inner clock.2 Cooler autumn afternoons create perfect conditions for a short, cozy afternoon nap or two to “catch up.”




  1. Harrison Y. The impact of daylight saving time on sleep and related behaviours. Sleep Medicine Reviews, Aug 2013; 17 (4): 285-292.


  1. Komaroff, Anthony, M.D. Editor in Chief, Harvard Health Publications. Daylight Saving Time “fall back” doesn’t equal sleep gain. Harvard Health Blog. November 1, 2013.
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