When the clocks “fall back” as Daylight Saving Time ends, you may feel tired and sluggish even though you’ve gained an hour of sleep. That’s because our bodies—more specifically, our circadian rhythms—need a little time to adjust. These daily cycles are run by a network of tiny, coordinated biological clocks.
Mike Sesma of the National Institutes of Health tracks circadian rhythm research being conducted in labs across the country, and he shares a few timely details about our internal clocks:
1. They’re incredibly intricate.
Biological clocks are composed of genes and proteins that operate in a feedback loop. Clock genes contain instructions for making clock proteins, whose levels rise and fall in a regular cyclic pattern. This pattern in turn regulates the activity of the genes.
2. Every organism has them—from algae to zebras.
Many of the clock genes and proteins are similar across species, allowing researchers to make important findings about human circadian processes by studying the clock components of organisms like fruit flies, bread mold and plants.
3. Whether we’re awake or asleep, our clocks keep ticking.
While they might get temporarily thrown off by changes in light or temperature, our clocks usually can reset themselves.
4. Nearly everything about how our body works is tied to biological clocks.
Our clocks influence alertness, hunger, metabolism, fertility, mood and other physiological conditions. For this reason, clock dysfunction is associated with various disorders, including insomnia, diabetes and depression.
So what can we do to help ourselves adjust to the time change?
“A lot of people like to stay up late on the weekend and then sleep in, but it’s important to stick to your regular schedule,” says Vanderbilt Sleep Disorders Center specialist Kelly Brown, M.D. “Mondays are already hard when you shift your sleep schedule on the weekends, and the time change makes it even harder,” Brown said.
Instead of sleeping for that extra hour on Sunday, Brown recommends using the time to go for a morning walk.
“Light is the most powerful way to control the internal clock. Getting sun exposure in the morning helps us feel more awake, and avoiding light at night, especially blue light from electronics, helps us fall asleep,” Brown said.
It usually takes just a day or two to feel normal again after changing clocks, but some people can require up to two weeks to make the transition. If the post-time change grogginess continues for more than two weeks, Brown says a sleep specialist may be able to help.
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