The debate over daylight saving time has resurfaced, with lawmakers considering making it permanent. While the idea of not changing clocks twice a year is appealing to many, sleep experts caution that permanent daylight saving time could have serious health consequences. The American Medical Association, the American Academy of Sleep Medicine, and the National Sleep Foundation all support eliminating clock changes but advocate for permanent standard time instead.
The body’s internal clock, or circadian rhythm is deeply influenced by light exposure. Morning light, with its shorter blue-green wavelengths, is crucial for regulating these rhythms. It enhances mood and alertness, while the longer orange-red wavelengths of evening light are more relaxing. Disrupting this natural cycle can lead to sleep disturbances and long-term health issues.
How Permanent Daylight Saving Time Disrupts Circadian Rhythms
The current system of switching between standard time and daylight saving time aims to balance bright mornings in winter with sunny evenings in summer. However, sleep experts warn that this practice comes with a cost. Research shows that heart attacks, strokes, traffic accidents, and workplace injuries increase in the days following the time change, particularly in the spring when people lose an hour of sleep.
The negative effects are most pronounced in the spring, when the time change can cause people to lose an hour of sleep. “The risk to any individual is small,” said Jamie Zeitzer, professor and co-director of the Center for Sleep and Circadian Sciences at Stanford University. “But when 300+ million people do this on the same day, you can see the effect.”
The Benefits of Permanent Standard Time
Following standard time aligns the body’s internal clock with natural light patterns. Our bodies are designed to wake up to morning light and embrace darkness in the evening. “Bright light in the morning actually helps us fall asleep at night,” said Dr. Beth Malow, a neurologist and sleep researcher at Vanderbilt University. “It seems kind of paradoxical, but by resetting our clocks, we’re ready to go to sleep at night.”
Shifting to daylight saving time in winter would mean many Americans wouldn’t experience sunrises until after 8 a.m. Waking up in darkness leaves the body without the light signal it needs to start its daytime routine. In contrast, bright evenings under standard time provide the necessary cues for a healthy sleep-wake cycle.
The Impact on Different Regions
Permanent daylight saving time would have varying effects across the country. For example, Los Angeles would see its latest sunrise at 8 a.m., while Sacramento and San Francisco would experience sunrises as late as 8:24 a.m. and 8:25 a.m., respectively. In the Northeast, cities like New York and Boston would see sunrises around 8:20 a.m. and 8:13 a.m., respectively.
The trade-off for later sunrises would be earlier sunsets. For instance, Los Angeles would enjoy sunsets at 5:44 p.m. shortly after Thanksgiving, compared to 4:44 p.m. under standard time. While this might seem beneficial, the health risks associated with disrupted circadian rhythms outweigh the benefits of longer evenings.
Sleep experts strongly advocate for permanent standard time to maintain the body’s natural circadian rhythms and promote
