It’s the National Sleep Foundation’s Sleep Awareness Week, a time to reflect on the importance of sleep. Sleep Week concludes with a large disruption to our sleep: Spring Forward. The original intent behind Daylight Savings was to save energy during World War I. On average, Americans lose 13 minutes of sleep that night, totaling over 74 million hours of sleep for the entire country.
Unlike other sleep disruptions during the year, the effects from Daylight Savings last for days after we change our clocks. Not all states observe Daylight Savings (Arizona and Hawaii), and even some countries forgo (for example, China). In the Southern Hemisphere the time changes are reversed (Australia). The US and Canada have larger disruptions to waketime than European countries, and I’m not sure why — if you think you know, let me know.
Circadian Rhythms in Time Zones (Interactive)
Daylight Savings changes are particularly disruptive to our sleep because of our circadian rhythms. Our body’s chemistry is aligned to sunlight, and it takes time to adjust when we change our clocks. We can see our circadian rhythms at work when looking at average bedtimes on either side of a time zone boundary. For example, take the Eastern Time / Central Time boundary slicing through the middle of Tennessee and Kentucky. Folks on the Eastern Time side of the boundary go to bed 16 minutes later than folks on the Central Time side. It’s because clocks on the Eastern Time side say that the sun rises and sets an hour later than clocks on the Central Time side. You can read more here. You can also see how having only one time zone for all of China affects people’s bedtimes.
So this week, instead of staying up too late binging on House of Cards, make a pledge: Today I Will go to bed early. It’ll help your body and mind get the sleep it needs. Happy Sleep Week from Jawbone!
Sleep Disruptions in 2014 and Circadian Rhythms Map. These studies were based on over one million UP wearers who track their sleep using UP by Jawbone. Less populous counties were blended with neighboring counties to generate significant results. This technique revealed patterns at finer granularity than the state level, such as time zone boundaries. Sleep deviations were calculated by removing the average sleep by day of the week. All data is anonymized and presented in aggregate.