Commentary
Video
The Health and Productivity Impacts of Time Changes in Different Populations
Experts discussed the negative health and societal effects of daylight saving time, advocating for a permanent switch to standard time to improve sleep, well-being, and productivity. [WATCH TIME: 6 minutes]
WATCH TIME: 6 minutes
Daylight saving time involves advancing clocks by 1 hour in the spring and returning to standard time in the fall, disrupting the alignment between the sleep-wake cycle and natural light exposure. This shift can negatively impact sleep health by reducing total sleep duration, altering circadian rhythms, and increasing sleep fragmentation. Research indicates that daylight saving time contributes to higher rates of sleep deprivation, particularly in individuals with preexisting sleep disorders, and is associated with increased risks of metabolic, cardiovascular, and cognitive impairments.1 The transition is especially challenging for those with rigid schedules, such as shift workers and students, who may struggle with prolonged circadian misalignment.
In collaboration with the American Academy of Sleep Medicine (AASM), NeurologyLive® held a roundtable discussion where sleep experts shared their clinical perspectives on the health impacts of the time change as well as solutions. The panelists in this conversation included clinical psychologist Jennifer Martin, PhD, who serves as professor of medicine at UCLA and was recently the past president of the AASM, neurologist and sleep medicine specialist Karin Johnson, MD, who serves as the cochair of the Coalition for Permanent Standard Time and the vice president of Save Standard Time, and pulmonologist Seema Khosla, MD, FCCP, FAASM, who practices sleep medicine in Fargo, North Dakota.
In this episode, sleep experts examined the significant health consequences of time changes, particularly for vulnerable populations such as shift workers, individuals with sleep disorders, and lower-income communities. They highlighted research linking daylight savings time to increased risks of cancer, heart disease, and mental health issues while emphasizing the benefits of standard time for circadian rhythm regulation. Citing global examples and historical data, they argue that maintaining standard time could enhance public health, improve workplace productivity, and reduce disparities in sleep-related health outcomes.
Transcript edited for clarity.
Isabella Ciccone, MPH: It's interesting that you all mentioned different types of patient groups—the teenagers versus the adults in the workforce. Are there any others that you think experience more pronounced disruptions with the time changes?
Seema Khosla, MD, FCCP, FAASM: Maybe. I would maybe offer the shift workers.
Karin Johnson, MD: I think anyone with an underlying sleep disorder. So here you go—yeah, sleep apnea, anyone who's already at risk with their sleep health—they're going to be more impacted.
Jennifer Martin, PhD: Yeah, and I think, I mean, the shift work group is a really vulnerable group because they have such a tendency to already be sleep-deprived that a little bit extra layered on top is really a challenge. And I—having worked with patients who are shift workers—one of them actually called it "the dreaded time change." He was already struggling and tired, and, you know, trying to manage having a family, getting his kids off to school, and all of those things, and then this on top of it. So I think that is across the board. And as Dr. Johnson mentioned, people with sleep apnea already have sleepiness and fatigue, along with a number of daytime symptoms that they struggle with. This just amplifies those problems.
Karin Johnson, MD: This is why the AASM, the American Academy of Neurology, CHEST, the American Medical Association—all these organizations have come together and said the data not only show we need to end time change to eliminate the harms of the acute switch, but that we really need to end it in favor of standard time. Because being on that more naturally aligned standard time does help long-term health. And we now have data showing that if you're delayed—like with daylight savings time—you have an increased risk of things like cancer, suicide, heart disease, and obesity. Circadian rhythms are just so important for all our body functions. They affect every cell in our body. And if we go to standard time, we can actually get the benefits—we get the power of the sun helping us be healthy without even having to do anything right away. Right now, we're causing this harm that we can't do anything about, and it's just another layer of negative effects.
As we talked about, there are populations that are affected more. This causes disparities—lower-income people who tend to have earlier jobs, people who are already sleep-deprived, people with medical problems. These are the people who are impacted the most, and we could significantly improve their health, well-being, and productivity at work. There’s even data showing that kids in school perform better—getting higher SAT scores—when they are on permanent standard time. That came out of Indiana when they used to do it. So,we know that we can help people feel better, improve mood. There's a lot of misconceptions—people think daylight savings time, because it's lighter at the end of the day, is better for mood. But the studies show the opposite—it actually worsens mood. So we can really help all these issues by going to standard time.
Seema Khosla, MD, FCCP, FAASM: It would be so lovely if we could learn from what we've done in the past, right? We've tried this—we tried it in the ‘70s, and it was supposed to last for a couple of years. But then they recognized that those dark mornings in the winter not only made children and adolescents more prone to depression, but it was also dangerous for them when waiting for the bus in the dark. So they had to end it before they had planned to because of these uncovered risks. Wouldn't it be lovely if we could just learn from that and maybe decide, "Okay, I think we are all in agreement that we don't like the switch, but perhaps now we could try permanent standard time."
Karin Johnson, MD: That’s what we’ve seen across the world. Mexico has just implemented permanent standard time and is now staying with it. Russia tried permanent daylight savings time for about three years and found it didn’t work, so they switched to permanent standard time. We have examples from across the world—there’s almost nowhere that is on a permanent daylight savings time schedule. But about 70% of the world is actually on standard time, and we know it can work.
Seema Khosla, MD, FCCP, FAASM: We also know there are a lot of pressures that our lawmakers face from different lobbying groups with financial interests. We would just ask that they pay attention to the health impacts—mental health, physical health. And we really want to emphasize that we need to ditch daylight savings time.
Karin Johnson, MD: I would argue that there is growing data on how sleep affects productivity—the workforce, and workforce health, and ensuring people show up to work and are productive. So there are economic reasons, too. If you want a healthy, productive workforce that shows up to work, your business—which is most businesses—should be in favor of standard time. Sure, some recreation and retail businesses may benefit more from daylight savings time. But for the majority of businesses, that’s not the case. Most people want their workers to be well, healthy, and productive—and those are the ones who benefit from standard time.
REFERENCES
1. Sleep experts push for adoption of permanent standard time for public health, safety, and efficiency. News Release. American Academy of Sleep Medicine. Published January 27, 2025. Accessed March 13, 2025. https://aasm.org/sleep-experts-push-for-adoption-of-permanent-standard-time-for-public-health-safety-and-efficiency
