Every spring, most states in the United States move their clocks forward by one hour to begin daylight saving time. Many people treat this change as a small inconvenience.
However, new research suggests that even this one‑hour shift may have real effects on health. A new study led by sleep and neurology experts at the University of California, Davis has found that the change to daylight saving time can increase migraine attacks and reduce deep sleep in people who already suffer from migraines.
The research was published in the Journal of Clinical Sleep Medicine and was led by neurologist and sleep specialist Dr. Sasikanth Gorantla. The study focused on how the spring clock change affects people who live with migraine, a neurological condition that is already closely linked to sleep and the body’s internal clock.
Migraine is not just a normal headache. It is a complex brain disorder that can cause severe pain and many other symptoms. Around 35 million people in the United States experience migraines, and globally it is one of the leading causes of disability.
Women are affected more often than men. Migraine attacks can cause throbbing head pain, nausea, vomiting, and strong sensitivity to light, sound, and smells. For many people, migraines can interrupt work, family life, and daily activities.
Doctors have long known that sleep patterns can influence migraines. The brain follows a natural 24‑hour rhythm known as the circadian rhythm. This internal clock controls when we feel awake or sleepy and helps regulate hormones, metabolism, and brain function.
Even small disruptions to this rhythm can affect the brain. People who live with migraines are especially sensitive to these changes. A small shift in sleep timing can sometimes trigger a migraine attack.
To better understand this relationship, the UC Davis research team studied what happens around the spring daylight saving time change. In the United States, clocks move forward one hour in March. While this may seem like a minor adjustment, it suddenly shifts the body’s schedule relative to the natural day‑night cycle.
The researchers followed 23 adults with episodic migraines for four weeks. The group included 22 women and one man. The study period covered two weeks before the daylight saving time change and two weeks after the clocks moved forward on March 12, 2023.
Participants recorded their headaches in a daily diary. They also used a special sleep sensor placed under their mattress. This device measured sleep patterns throughout the night. The sensor tracked different stages of sleep, including deep sleep, which is the stage when the body and brain recover and restore themselves.
The researchers carefully defined migraine days. A headache was counted as a migraine if it had at least two of several typical features. These included one‑sided head pain, throbbing or pulsating pain, moderate to severe intensity, or pain that became worse during normal physical activity.
Migraines could also include symptoms such as nausea, vomiting, or sensitivity to light and sound.
Other headaches that did not meet these criteria were recorded as non‑migraine headaches. These are usually milder and are often described as dull or aching pain. Participants also recorded how strong their headaches were and what medications they were taking to prevent migraines.
Because hormones can also trigger migraines, the researchers excluded migraine attacks that occurred close to participants’ menstrual cycles. Hormonal changes during this time are known to affect migraine risk, so the scientists wanted to remove this factor from their analysis.
Not every participant provided the same number of diary days. To make the results fair, the researchers calculated the number of migraine or headache days per 100 person‑days. This statistical method adjusts the results so that people who recorded fewer days did not affect the final findings.
When the researchers analyzed the data, they found a clear pattern. The number of migraine attacks increased noticeably after the daylight saving time change.
Before the clock shift, participants experienced about 7.76 migraine days per 100 person‑days. After the shift, the number rose to 13.35 migraine days per 100 person‑days. This nearly doubled the frequency of migraines.
Interestingly, the intensity of the headaches did not change significantly. In other words, the migraines were not necessarily more painful, but they occurred more often.
The study also found changes in sleep quality. Deep sleep dropped after the time change. Before the clock shift, participants averaged about 94 minutes of deep sleep each night.
After daylight saving time began, this number fell to around 84 minutes. Total sleep time stayed roughly the same, meaning people were sleeping about the same number of hours but getting less restorative sleep.
Deep sleep is an important stage of the sleep cycle. During this stage, the brain performs many important functions. It clears metabolic waste products, strengthens memory, and supports physical recovery. Losing deep sleep can affect many aspects of health, including brain function and pain sensitivity.
Dr. Gorantla explained that even a small disruption to the body’s internal clock can affect people who live with migraines. The increase in migraine attacks and the drop in deep sleep suggest that stable sleep patterns are important for managing migraine conditions.
The results also support growing concerns among sleep researchers about the health effects of daylight saving time. Circadian rhythm disruptions have been linked to many problems, including poor sleep, heart issues, and mental health challenges. Similar disruptions can occur during jet lag or when people frequently travel across time zones.
Although scientists do not yet fully understand how circadian disruption triggers migraines, the researchers believe deep sleep may play an important role. If deep sleep decreases, the brain may not be able to remove waste products as effectively. This could affect brain function and increase migraine risk.
To reduce the impact of the daylight saving time change, experts recommend preparing the body in advance. Gradually adjusting sleep schedules by going to bed slightly earlier each day can help the body adapt.
Keeping a regular sleep routine, reducing caffeine late in the day, limiting bright evening light, and getting morning sunlight exposure can also help reset the internal clock. Regular exercise and careful attention to common migraine triggers such as alcohol, dehydration, and stress may also help reduce attacks.
The American Academy of Sleep Medicine has suggested that the United States should consider staying on standard time year‑round. Experts believe this schedule better matches the body’s natural circadian rhythm and may support overall health.
Overall, this study highlights how sensitive the human brain can be to even small changes in daily timing. While daylight saving time may appear to be a simple clock adjustment, the research suggests it can have measurable effects on sleep and neurological health.
For people living with migraines, maintaining stable sleep patterns may be one of the most important strategies for reducing attacks and protecting brain health.
If you care about pain, please read studies about how to manage gout with a low-purine diet, and a guide to eating right for arthritis.
For more health information, please see recent studies about the link between processed foods and chronic diseases, and avoid these 8 foods to ease arthritis pain.
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