Daylight Saving Time vs. Standard Time: Which Is Better for Your Health?

Israel recently switched to winter time, and the United States turned its clocks back a few days later. Every year, these changes reignite a familiar debate: Wouldn't it be better to keep the same time throughout the year? And if so, should we adopt permanent daylight saving time or standard time?

A new study from the University of Washington, published in the journal Current Biology, examined what would happen if the United States adopted permanent daylight saving time. Researchers analyzed school start times, student enrollment figures, and school locations across 14 states that had already approved legislation supporting such a change.

Their findings revealed a concerning consequence: At least two billion additional school commutes would take place before sunrise each year. Researchers emphasized that this figure is likely an underestimate, since their calculations assumed that students leave home at approximately 8 a.m.

"Nobody wants their children going to school in the dark," said Professor Horacio de la Iglesia, the study's senior researcher.

Why Morning Sunlight Matters for Sleep and Health

Beyond concerns about children's safety, the researchers highlighted the importance of morning sunlight in regulating the body's internal clock, known as the circadian rhythm. This biological system helps regulate sleep, mood, appetite, and other essential functions.

Morning light serves as a natural signal that helps synchronize our internal clock with the 24-hour day. As evening approaches, the body begins increasing its production of melatonin, the hormone that helps prepare us for sleep. Exposure to bright light late in the evening can delay this process, making it harder to fall asleep and potentially disrupting our natural sleep-wake cycle.

Sleep researchers at Stanford University have previously reached a similar conclusion: Maintaining a consistent time throughout the year is preferable for health to changing the clocks twice annually, with permanent standard time emerging as the healthiest option.

Four Simple Habits to Improve Your Sleep

Regardless of whether the clocks change, there are practical steps you can take to support your body's natural rhythm and improve sleep quality.

1. Get outside shortly after waking. Try to spend some time outdoors during the first hour after getting up. Even a few minutes on a balcony can help expose you to natural morning light.

2. Let daylight into your home. Open curtains and blinds as soon as you wake up. Natural daylight is significantly brighter than most indoor lighting and helps signal to your body that the day has begun.

3. Reduce bright light in the evening. Limit screen exposure and switch to softer lighting during the hour before bedtime. This can help your body prepare for sleep by supporting its natural melatonin cycle.

4. Maintain a consistent wake-up time. Try to wake up at approximately the same time each day, including Fridays and weekends whenever possible. A regular schedule helps reinforce your internal biological clock.

When Winter Fatigue May Be More Than Just Tiredness

For some people, the transition to shorter days brings more than an adjustment to their sleep schedule. Reduced daylight can affect mood and energy levels, and persistent changes may sometimes indicate a seasonal mood disorder. If you experience a significant decline in mood that lasts for several weeks, particularly during the winter months, consider speaking with your family doctor.

Although we may not be able to control national decisions about daylight saving time, we can take steps to support our body's natural rhythms. By prioritizing morning sunlight, reducing evening light exposure, and maintaining consistent sleep habits, we can make the seasonal transition easier on both our physical and emotional well-being.