It’s 7 a.m. on a winter day, and your alarm is blaring. If you’re in eastern Maine, sunlight is already streaming through your bedroom windows. If you’re in western Michigan, the sun won’t make an appearance for another hour. Although both locations fall in the Eastern time zone, they have very different daylight patterns—with implications for your well-being.
“Where you’re located in a time zone can have a surprising effect on your body’s rhythms,” says Jennifer M. Burgess, D.O., a primary care physician at Henry Ford Health.
At the easternmost edge of a time zone, the sun rises early and sets early. On the far western end, sunrise and sunset are both shifted later. Those differences can affect your mood, your energy levels and even your health.
Time Zones, Sunlight and Circadian Rhythms
Exposure to light plays a key role in your body’s sleep-wake cycle, also known as a circadian rhythm. “Sunlight is a really important cue that tells our body when it’s time to wake up and time to sleep,” Dr. Burgess explains.
When light gets low, your body produces melatonin, a natural hormone that makes you feel sleepy. Bright light in the morning, by contrast, causes melatonin levels to dip, helping you feel more alert. A daily schedule that’s mismatched with your spot on the map can lead to groggy mornings and trouble sleeping at night.
Sunlight and Health
Mood changes are some of the most obvious effects of a time-zone mismatch, Dr. Burgess says. “Less exposure to sunlight, especially in the winter, can lead to seasonal affective disorder,” she says. Seasonal affective disorder (SAD), sometimes called the “winter blues,” is a type of depression triggered by shorter, darker days.
Being out of sync with your sleep-wake cycle can also lead to sleep troubles like insomnia. A bad night’s sleep can cause you to feel sluggish and moody. You might have trouble making decisions or paying attention.
Over the longer term, sleep deprivation can increase the risk of health problems such as:
- Dementia
- Depression
- Heart disease
- High blood pressure
- Kidney disease
- Obesity
- Stroke
- Type 2 diabetes
Tips for Healthy Sleep-Wake Cycles
What can you do if your zip code is at odds with your circadian rhythm? Fortunately, you don’t have to move to the opposite side of the time zone to get a good night’s rest. Dr. Burgess offers tips to support a healthy sleep cycle. “These are good habits that support healthy sleep regardless of the time of year or the place where you live,” she says.
- Stick to a schedule: Encourage healthy sleep patterns by going to bed and waking up around the same time each day.
- Lighten up: Expose yourself to bright light first thing in the morning. If the sun is shining, open the windows or go for a walk. When sunlight is in short supply, consider getting a UV lamp that mimics natural sunlight. “LED lightboxes can be so helpful for telling your brain it’s time to wake up and start the day,” Dr. Burgess says.
- Unplug: In the evening, bright light from your phone or other electronic devices can trick your brain into thinking it’s still daytime. To get your brain and body ready for sleep, turn off devices an hour or two before you plan to go to bed. Try dimming the lights and engaging in a quiet activity, like reading a book or doing a crossword puzzle.
- Be careful with supplements: Many people are tempted to take over-the-counter melatonin supplements if they have trouble sleeping. While supplements can be helpful in certain short-term situations—such as dealing with jet lag on an overseas trip—they aren’t recommended as a long-term fix, Dr. Burgess says. “It’s important to ask your doctor for guidance about taking supplements like melatonin,” she adds.
If you’re still waking up sleepy or struggling to fall asleep at night, Dr. Burgess encourages talking to a doctor. While the timing of sunset and sunrise can have small effects on your sleep-wake cycle, there are many other causes of restless sleep.
A sleep study can help diagnose the problem and point to solutions—whether you struggle with insomnia as you age, wake up exhausted because of a disorder like obstructive sleep apnea or have some other type of sleep difficulty.
“Bottom line, you should be able to get a good night’s sleep no matter where you live or what part of the time zone you’re in,” Dr. Burgess says. “If you’re struggling, treatments are available.”
Reviewed by Jennifer M. Burgess, D.O., a family medicine doctor at Henry Ford Health. She sees patients at the Henry Ford Center for Athletic Medicine in Detroit.
