How does time change affect diabetes?

Changes in time due to seasonal time changes or changes in time zones resulting from travel may present unique challenges in managing diabetes.

This article explores how seasonal time changes, such as daylight saving time, and traveling across time zones can impact your health. It also offers tips for managing diabetes during these changes.

Our bodies function like highly tuned machines. When it’s time to wake up in the morning, our body knows to release cortisol, a stress hormone. In ancient times, this stress hormone was vital in helping us escape a dangerous situation, but today, cortisol helps us get out of bed. 

That release of cortisol triggers an increase in glucose (sugar) production by the liver. When this happens for people with diabetes, it creates a need for an increase in insulin to adjust glucose levels. Optimally performing cortisol follows a pattern called the ‘cortisol curve’. In a healthy curve, cortisol is high in the morning and tapers off through the day and evening, like a slow-release energy pill that wears off just in time before going to sleep.¹ 

Once we are in a routine of waking up and going to bed around the same time each day, our bodies know when to release these stress hormones, and our diabetes medication has been timed accordingly. But when we experience a time change, our bodies can feel disoriented, especially in the first week, and it may take some time to get back in balance

Your body may need some time to adjust to a seasonal time change or a change in time zones. However, if your energy starts to run low during familiar activities, it could be a warning that your cortisol pattern is disrupted. Catching more colds or experiencing mood swings more frequently, as well as having a shorter emotional fuse, are other early signs.¹ Talk to your healthcare team if you are experiencing any of these signs.

Daylight savings time (DST) is done in many parts of the world where clocks are adjusted forward in the spring and backward in the fall to make better use of daylight. The time changes as part of daylight savings can disrupt sleep patterns,² potentially affecting the delicate balance in your diabetes management and normal blood sugar levels.

Spring

In spring, many people around the world set their clocks forward, which means more sunlight and longer days ahead. But the first few weeks following this time change can be challenging. Losing an hour can make you feel a little drowsy over the next few days, and your glucose levels may be affected.

Fall

While gaining an extra hour of sleep in the fall sounds fantastic, this time change can also affect people with diabetes. The shift might lead to changes in insulin requirements and timing, as well as fluctuations in blood glucose levels.⁴ You may sleep more, but there is also a potential adjustment period for diabetes management.

Time zone changes or daylight savings time can disrupt your morning routine. When dealing with these adjustments, you’ll want to keep an eye out for the dawn phenomenon. 

The dawn phenomenon, often referred to as the “morning rise” in blood sugar levels, is a notable factor in diabetes management. In type 2 diabetes, the body becomes even less sensitive to insulin, which leads to higher blood sugar levels in the morning. Blood glucose levels tend to increase from their lowest point during the night to the level right before breakfast. New research using continuous glucose monitoring (CGM) shows that this phenomenon is quite consistent.³ 

To manage the dawn phenomenon, it's essential to find a personalized solution with the guidance of your healthcare team. Solutions may include adjusting your diet, incorporating extra exercise in the morning and evening, or considering medication.⁴

Travel

When you travel with diabetes , crossing time zones can be a bit more complex. Adjusting to a new time zone can disrupt meal and medication schedules, impacting your blood sugar levels. Because the body's internal clock can struggle to keep up with the time changes, diabetes management requires extra attention. This shouldn’t deter people with diabetes from enjoying travel, but rather serve as a reminder to plan ahead to carefully maintain glycemic control.

Jet lag is another factor that can impact your glucose levels and sleep. Jet lag is a result of crossing multiple time zones,⁵ and disrupts your body's internal clock. Jet lag symptoms and effects increase based on the number of time zones crossed, especially when traveling eastbound. Changes in lighting, meal timing, and exposure to artificial light can contribute to fatigue, low mood, and sleep issues. To deal with jet lag symptoms and effects:⁶

• Drink plenty of water instead of alcoholic or caffeinated drinks.

• Eat the normal amount at your normal meal times.

• Stay awake while it’s still light out and try to sleep when it gets dark. 

• Avoid artificial lights when possible.

Summary

Here are some key takeaways to help you manage the effects of time zone changes and daylight saving time on your sleep and diabetes:

• Adjust your blood glucose meter: Ensure your blood glucose meter reflects the correct time after a seasonal time change.
• Maintain routine: To stay physically and mentally healthy during a time change, it's important to maintain a consistent daily routine. When your daily rhythms are off track, it can lead to a variety of physical and mental health issues. Stick to your usual daily routine as closely as possible, including meal times, exercise, and sleep schedules.
• Monitor blood sugar levels: Keep a close eye on your blood sugar levels during the transition period and be prepared to make necessary adjustments to your diabetes medication or insulin dosages in consultation with your healthcare provider.
• Prioritize sleep: The importance of sleep cannot be overstated. Pay extra attention to your sleep schedule and try to get adequate rest during this adjustment period.
• Stay connected: Keep in touch with your healthcare provider or team if you experience persistent disruptions in your diabetes management or sleep patterns. Reach out to your healthcare team for guidance on how to improve your sleep, meal timing, or other health-related concerns. They can offer personalized advice to help you get back on track.

Sources:

1. How to balance your cortisol levels naturally [Internet]. Experience Life. 2023 Mar 7 [cited 2025 Jul 9]. Available from: https://experiencelife.lifetime.life/article/the-cortisol-curve/
2. Manfredini R, Fabbian F, Cappadona R, Modesti PA. Daylight saving time, circadian rhythms, and cardiovascular health. Intern Emerg Med. 2018;13(5):641-646.
3. Monnier L, Colette C, Dejager S, Owens D. The dawn phenomenon in type 2 diabetes: How to assess it in clinical practice? Diabetes Metab. 2015;41(2):132-137.
4. Zheng X, Qi Y, Bi L, et al. Effects of Exercise on Blood Glucose and Glycemic Variability in Type 2 Diabetic Patients with Dawn Phenomenon. BioMed Res Int. 2020;2020:e6408724.
5. Mason IC, Qian J, Adler GK, Scheer FAJL. Impact of circadian disruption on glucose metabolism: implications for type 2 diabetes. Diabetologia. 2020;63(3):462-472.
6. Herxheimer A, Waterhouse J. The prevention and treatment of jet lag. BMJ. 2003;326(7384):296-297. 

_{Before making any changes to your lifestyle or medication, please speak to your healthcare professional to check that it is suitable for you.}

_{This content is provided for general information only. It is not intended to amount to advice on which you should rely – you must obtain professional or specialist advice from your healthcare professional before taking, or refraining from, any action on the basis of the content. Although we make reasonable efforts to ensure that the content is up to date, Roche makes no representations, warranties or guarantees, whether expressed or implied, that the content is accurate, complete, up-to-date or that it should be relied upon.}