For most of us the end of daylight saving time means one thing: an extra hour of sleep. One extra hour tonight isn’t going make that much of a difference in the long run. What might have a longer lasting effect on us though is changing the time the sun sets.
The reason we start daylight saving time every spring is so that we can tack on an extra hour of daylight to our evenings. The flip side of this perk is that it feels like we’re losing an hour of daylight when it ends every fall. We’re also losing daylight hours as we approach winter, so by the time the solstice arrives on December 21st the sun will be setting at 4:36 in Huntsville. That’s a time of day that many people still consider the afternoon!
Light is a key player in our circadian rhythm, the 24 hour cycle we go through each day that keeps us on track. When it’s dark our bodies produce melatonin, a hormone that helps regulate your rhythm and helps put you to sleep. Then light helps you wake up in the morning, keeping your rhythm going. When the time of the sunset is manipulated it can throw off this rhythm. The sunset will shift from 5:49 to to 4:48, but your work day isn’t going to start at 8:00 instead of 9:00 after Sunday. Our bodies can have a lot of difficulty adjusting to this, which can then lead to trouble sleeping.
Timing is important, but just getting sunlight can be important too. A lack of sunlight during the cooler months is thought to be one of the causes of seasonal affective disorder (SAD). An earlier sunset could affect melatonin levels, making you feel excessively tired and a drop in sunlight has been found to correlate with a drop in Serotonin, which could lead to depression. There’s still a lot of research needed to fully understand SAD; it’s likely caused by a combination of factors. Light therapy is an effective treatment for many though.