The Health Impacts of Daylight Saving Time and the Rise of Permanent Standard Time

As many Americans prepare to “spring forward” and lose an hour of sleep on March 10th, a growing body of evidence suggests that the twice-yearly ritual of changing clocks is detrimental to public health. Whereas the debate over daylight saving time (DST) continues, a shift towards permanent standard time is gaining momentum, supported by sleep scientists and public health experts. British Columbia recently made headlines by adopting permanent daylight saving time, a move that, while popular with residents, is viewed with caution by many in the medical community.

Why Daylight Saving Time is Detrimental to Our Health

Our bodies operate on an internal circadian rhythm – a natural, internal process that regulates the sleep-wake cycle and influences various physiological functions, including cardiac and metabolic pathways. This rhythm is heavily influenced by light exposure. When we wake up and are exposed to sunlight, it signals the brain to initiate wakefulness and prepare the body for the day.

According to Emily Manoogian, a senior staff scientist at the Salk Institute and an executive member of the Center for Circadian Biology at University of California, San Diego, disrupting this natural alignment with artificial time changes has negative consequences. “Light is the largest cue to coordinate behavior,” she explains. When morning light is absent, the body struggles to recognize it as morning, leading to difficulties waking up and potential disruptions to metabolic processes.

The consequences extend beyond simple sleepiness. Research indicates that the spring forward to DST is associated with an increase in adverse health events, including:

• Increased risk of heart attacks and strokes
• Higher rates of car accidents
• Worsened metabolic function

A study published in the Proceedings of the National Academy of Sciences in September 2025 found that switching clocks twice a year takes a significant public health toll, primarily by increasing the number of strokes and obesity cases. The study also suggested that adopting permanent standard time could prevent 300,000 strokes and over 2 million cases of obesity annually.

Permanent Standard Time: A Healthier Option?

The growing consensus among health professionals is that aligning our clocks with our natural circadian rhythms through permanent standard time offers substantial health benefits. “When we can realign better to our environment, we get better sleep,” says Manoogian. “We have lower risks of almost any chronic disease you can imagine – cardio-metabolic, cancer, even depression, bipolar disorder.”

While permanent daylight saving time might seem appealing – offering more daylight hours in the evening – research suggests that permanent standard time is the more beneficial option. The Stanford study mentioned previously found that permanent daylight saving time reduced strokes and obesity, but to a lesser extent than permanent standard time.

Mitigating the Impact of Daylight Saving Time

If you are concerned about the health effects of the upcoming time change, here are some strategies to help your body adjust:

• Maximize Morning Light Exposure: If the sun is shining, spend time outdoors in the morning. If it’s dark, use bright lights indoors.
• Prioritize Sleep: Aim for 7-9 hours of quality sleep each night, maintaining a consistent sleep schedule.
• Consistent Meal Times: Eat meals at regular times each day to support metabolic regulation.
• Gradual Adjustment for Children: Shift children’s bedtimes and wake-up times by 20 minutes each day for three days leading up to the time change.

Looking Ahead

The debate surrounding daylight saving time is far from over. As more research emerges highlighting the health risks associated with clock changes, the movement towards permanent standard time is likely to gain further traction. Prioritizing our natural circadian rhythms is not just about getting a good night’s sleep; it’s about safeguarding our overall health and well-being.