Diabetes and daylight saving time

Red alarm clock showing 12 o'clock next to a bouquet of yellow and red tulips, with a blurred green background.

Key takeaways:

  • Daylight saving time can shift your blood sugar by disrupting your usual meal, exercise and sleep routines

  • Most insulin pumps and many CGMs don't update their clocks automatically—and a wrong clock can mean the wrong insulin dose at the wrong time

  • Research has found glucose control can slip in the weeks after both the spring and fall changes

  • What to do: Reset your device clocks by hand and check your blood sugar more often for the first week 

It happens twice a year, like clockwork: In spring, we jump forward and lose an hour. In the fall, we gain that precious hour back. You might be prepared for the calendar mix-ups that daylight saving time (DST) changes bring. But what you might not know is that time changes can have quite an impact on your diabetes too.

It’s possible that someday, twice-yearly time changes will become a thing of the past. Congress is debating whether to end the practice. The House passed a permanent DST bill in July 2026, but it hasn’t cleared the Senate. For now, the clocks are still changing. Here’s what to watch out for, plus tips to prepare.

Blood sugar bounce-arounds: How time changes affect glucose levels

When the time changes, your routines change too. And even small shifts can have a big impact on your blood sugar levels, especially in the days just after. For example, you might celebrate longer spring days with more indulgent meals. Those rich foods and extra treats can send your blood sugar soaring. Or when you wake up in the pitch dark, you may stay snuggled in bed instead of heading out on your daily walk. While skipping out on exercise one day isn’t the end of the world, a pattern of missed workouts can wreak havoc on your blood sugar levels.

Monitor mishaps: Why your insulin pump and CGM clocks matter

The clocks on some diabetes devices, like your insulin pump and your continuous glucose monitor (CGM), don’t automatically adjust for DST changes. And when your pump or CGM is set to the wrong time, you’re at an increased risk for both higher and lower blood sugar. 

Michigan State University clinicians have called for an end to DST specifically to protect insulin pump users, in a 2025 article in Clinical Diabetes, a journal of the American Diabetes Association. One of the authors, a nurse practitioner who uses a pump herself, accidentally flipped hers from a.m. to p.m. during a time change and developed hyperglycemia as a result.

Sleep struggles: How lost sleep raises blood sugar

When the time shift makes the days longer, your sleep can get disrupted. That’s because the extra light keeps your body from producing the melatonin you need to get a good night’s sleep. 

Sleep is important for pretty much every part of your life: mood, digestion, concentration, stress response. But it’s especially important for people with diabetes. Lost or poor-quality sleep can make your blood sugar levels rise. But sleep may not be the whole story. A 2024 study in Diabetes Research and Clinical Practice tracked CGM data from adults with type 1 diabetes across both time changes. In the weeks after each switch, participants spent less time in their target range and more time high. The effect showed up regardless of how well they slept, suggesting the circadian disruption itself plays a role.

Tips for managing your diabetes during daylight saving time

Whether you’re gaining an hour or losing it, here’s how to adjust your treatment plan and keep your blood sugar levels nice and steady:

Increase your blood sugar checks

Checking more often, especially in the first week after the time change, helps you stay on track while your body adjusts to the environmental changes, as well as shifts to your own schedule. And more frequent checks will help you catch any problems early.

Check the time on your devices

Make sure all your diabetes management devices are set to the correct time once a time change happens. To make sure you don’t forget, put alerts in your calendar for both the spring and fall time-change dates. Clocks fall back on Sunday, November 1, 2026, and spring forward again on Sunday, March 14, 2027.

Stay active

Regular exercise helps keep your blood sugar levels balanced. The longer days of spring give you more time to get out and get moving. Use that extra hour you get back in fall to find a new indoor workout you can do no matter the weather. 

Stick to your routines

There’s a lot of power in habits, so keeping to your regular exercise and eating schedules makes it easier to manage your diabetes no matter what’s happening with the clock. 

Keep bedtime consistent

Though you may be tempted to squeeze every minute of extra sunlight when DST comes, try to go to bed at about the same time as before the change. This helps regulate your sleep cycle and keeps your blood sugar steady. (Bonus tip: It also helps to keep your bedtime consistent whether it’s a weekday or the weekend).

Stay consistent

No matter what snafus a time change throws at you, our best advice remains the same. Make healthy food choices. Move your body every day. Keep your stress levels low. And keep up with your blood sugar checking habit.

Double-check a.m. vs. p.m.

When you adjust the time on your insulin pump or CGM, make sure it’s set correctly to a.m. or p.m. When your pump or CGM is set to the wrong time, you’re at an increased risk for both higher and lower blood sugar.

FAQs

  • Most don’t. Unlike your phone, most insulin pumps—and many CGMs—need to be reset by hand. Do it as soon as the time changes, and double-check that you haven't accidentally flipped a.m. and p.m. That's a common mistake, and it can mean getting the wrong amount of insulin at the wrong time of day.

  • It can. A 2024 study in Diabetes Research and Clinical Practice followed adults with type 1 diabetes through both time changes. Researchers found that people spent less time in their target glucose range, and more time above it, in the weeks afterward. Shifting routines, disrupted sleep and incorrect device clocks can all contribute.

  • Spring is usually the tougher one. You lose an hour of sleep, and the shift tends to be more abrupt. But research has found glucose control can slip after both transitions, so it’s worth paying closer attention either way.

  • Most people settle into a new rhythm within a week or so, though it varies from person to person. Studies have observed glucose changes over the weeks following a transition, so plan to monitor a little more closely than usual for at least the first week and look for patterns rather than reacting to any single reading.

  • Not on your own. Any change to your insulin should come from your diabetes care team, who can look at your readings alongside your full treatment plan. What you can do yourself: Reset the clocks on your devices and check your blood sugar more often for the first week.

  • Reset it as soon as you notice and confirm the a.m./p.m. setting is correct. Then check your blood sugar more frequently through the rest of the day. If your readings are unusually high or low, or you think you may have received the wrong dose, contact your care team.

  • Clocks fall back on Sunday, November 1, 2026, and spring forward again on Sunday, March 14, 2027. Congress has debated ending the twice-yearly switch. The House passed a permanent daylight saving time bill in July 2026, but it hasn’t become law, so the time changes are still on.

    • Aldasouqi S, Sullivan K, Teitelbaum HS. A call from health care providers and a patient to end daylight savings time. Clin Diabetes. 2025;43(1):125-127. doi:10.2337/cd24-0040. Accessed August 31, 2026.
    • Angelino S, Longo M, Caruso P, et al. Sleep quality and glucose control in adults with type 1 diabetes during the seasonal daylight saving time shifts. Diabetes Res Clin Pract. Published online September 17, 2024. Accessed August 31, 2026.
    • Malow BA. It is time to abolish the clock change and adopt permanent standard time in the United States: a Sleep Research Society position statement. Sleep. 2022;45(12):zsac236. doi:10.1093/sleep/zsac236. Accessed August 31, 2026.
    • Di Gioia L, Di Molfetta S, Giordano F, et al. 981-P: Transition from standard time to daylight saving time and vice versa: effects on FGM metrics in patients with autoimmune diabetes. Diabetes. 2023;72(Suppl 1):981-P. doi:10.2337/db23-981-P. Accessed August 31, 2026.
    • Sleep Foundation. Latest updates on daylight saving time legislation and change. Accessed August 31, 2026.

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This content is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

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