What the midnight sun shows about sleep, light and seizures

You don’t have to live near the North Pole for this to matter to your sleep. A review of studies from the Arctic and Antarctic found that sunlight, the main signal that sets your body clock, shapes how long and how well people sleep. Researchers also saw a link to seizures. If you or someone you love has epilepsy, the findings speak to you directly. If not, they still say something useful about how light and sleep work for everyone.

The researchers say the poles are not a special case. What they saw there holds lessons for people everywhere.

How the study worked

This was a review, which means the authors gathered and compared earlier research instead of running a new experiment. They looked through 2337 studies on seizures, light and sleep in people living in the Arctic or Antarctic. It was published Oct. 28, 2026, in the Journal of Biological Rhythms. Only a handful of studies looked at seizures directly, and the path from light to sleep to seizures is the authors’ proposed explanation for the pattern.

Why look at the poles?

Near the poles, sunlight changes more than almost anywhere else. Summer brings the midnight sun, when the sun stays up around the clock. Winter brings midday darkness. Because these swings happen every year, the poles work like a natural laboratory for studying what light does to the body.

Sleep and seizures are known to affect each other. Poor sleep can set off seizures, and seizures can disturb sleep. Light is the main thing that tells your body clock when to be awake and when to rest.

What they found

After filtering, the review kept 5 studies on status epilepticus and 36 on sleep. Status epilepticus is the most extreme kind of seizure, one that goes on for a prolonged time. Here is what the researchers saw:

• Seizures: Status epilepticus went up as days grew longer going into summer at high latitudes.
• Body clock: More sunlight going into summer moved people’s body clocks earlier. Less sunlight going into winter moved them later. In the most extreme cases, the body clock stopped following the day and ran on its own schedule.
• Sleep: Both very bright and very dark stretches were linked to shorter sleep and more broken sleep.

The authors suggest a simple chain of events. Bright summer light moves the body clock earlier, which shortens and breaks up sleep. That, in turn, could trigger more seizures.

The authors also point out that about 1 in 10 people will have a seizure at some point in their lives. That is one reason they say the findings matter for everyone.

What is a body clock, anyway?

Scientists use the word chronotype for whether you naturally lean toward early mornings or late nights. Light helps set it. The review found that this setting shifts in a steady, predictable way as the amount of sunlight changes.

You may notice a mild version yourself. Long summer evenings can make it harder to wind down, and dark winter mornings can make it harder to get going.

What you can do today

You can’t change the sun, but you can give your body clock clearer signals. Try these two steps. They fit the idea at the heart of the review, that light shapes sleep.

• Get daylight early. Spend a few minutes outside in the morning, even on a cloudy day. A walk with your coffee or time on the porch counts.
• Keep your bedroom dark at night. If light slips in around the edges, try blackout curtains or a simple sleep mask. They are widely sold at drugstores and big-box stores.

If you have epilepsy, steady sleep times and a dark bedroom are a good habit to build. Ask your neurologist before a trip across time zones. Either way, tonight is a good time to look at your bedroom and see how dark it really is.