Generally speaking, in what ways does the upcoming fall back time change impact people’s sleep and overall health?
With an hour “gained,” people will likely wake up at an earlier time and get sleepy at an earlier time. Maintaining a consistent sleep schedule is harder with this change, and the disruptions to sleep could end up decreasing sleep duration.
Sleep is regulated in our body, for one, by the body clock, which works with other physiological clocks that regulate other functions like hormones, body temperature, appetite, and metabolism. Disturbance in one will cause disturbances in other clocks.
Who is more vulnerable to being affected by the time change?
After fall back occurs, older adults generally have more sleep problems and people with depression have worse moods.
Evening chronotypes have more problems than morning types — less so than after the “spring forward” time change occurs, but it often still takes close to two weeks to adjust.
What recommendations do you have to lessen these impacts? What can people do to support their sleep amid the change?
In general, shifting sleep gradually is the most effective strategy. For the first few days, I recommend bright light exposure in the evening while limiting it in the early morning to help shift the body clock to later, although this is more helpful for people who tend to wake up too early. Most people adjust to the change within one to two weeks.
I also recommend moving bedtime and wake time 10-15 minutes later each day for a few days before and after the change. After work, take a 30-minute walk or have 30 minutes of light exposure. Avoid things that disrupt sleep like caffeine and alcohol around the fall back time change.
Do you have any tips for parents as they help their children navigate the time change?
Additional tips for parents are to keep their children’s bedtime, meal, and morning routines stable, even if the times are shifting. Outside playtime in the late afternoon or early evening could be helpful. Maintain overall sleep practices for the bedroom environment with respect to light and noise, so ensure electronics are off at least one hour before bed and devices kept out of the bedroom.
Are there differences in how spring forward versus fall back affects our sleep schedules? Is one easier to adjust to?
With spring forward, you are losing time and morning light as well as delaying melatonin release because of the evening light, which can disrupt sleep and daytime alertness. Some studies have found a 4% higher risk of heart attack as well as increased workplace and traffic accidents in the week after the change.
During fall back, there is mixed data, although it is overall more positive compared to spring forward. A 2025 publication comparing the two transitions found fewer incidents of cardiovascular disease and psychiatric emergency visits for several weeks after fall back and little changes after spring forward. This is corroborated by other recent studies, but it is contrasted by a Canadian aging study which found more self-reported sleep dissatisfaction, insomnia, and daytime sleepiness after fall back compared to after spring forward.
An ongoing debate is whether there should be an end to changing the clocks and instead have permanent daylight saving time or permanent standard time. From a health and sleep perspective, do you see benefits to having a permanent time rather than changing the clocks?
There are arguments for keeping a permanent time rather than changing the clocks twice a year. Stanford researchers created a model and analyzed county-level data which anticipated that changing to either permanent standard time or permanent daylight saving time could decrease obesity and stroke prevalence — to a greater degree for permanent standard time compared with permanent daylight saving time. Other experts cautioned that this approach has limitations and its prediction is therefore incomplete.
To what extent do you agree that permanent standard time is a healthier choice compared to permanent daylight saving time?
The consensus favors permanent standard time. Most sleep and medical societies cite the better alignment of the solar cycle with the human circadian cycle, as well as a link between permanent daylight saving time with depression, cardiovascular disease, metabolic syndrome, and other disorders.
However, one systematic review found some evidence that in the summer, daylight saving time is associated with lower all-cause mortality and fewer traffic accidents.
Keep in mind, though, that most of the evidence is gathered from studies of acute clock changes or from modeling data. There are some conflicting results, and actual permanent time studies have not been done long term.
In this debate, people often discuss the importance of sunlight. How does sunlight impact our sleep and circadian rhythm?
Light is one of the major signals to the brain that sets the circadian clock. It is conveyed through the eyes to regions of the brain in the regulatory pathway that involves melatonin and other neurotransmitters. Sunlight is highly effective because it is very bright, and in the early morning, exposure helps to set earlier sleep timing and better sleep quality.
On the other hand, artificial lighting exerts a crucial influence on our society. Its effect is particularly noticeable in teens. Ordinary room light and light-emitting electronic devices delay melatonin release, which can delay the sleep phase and cause social jet lag.
One of the deliberations is the value of having more sunlight earlier versus later in the day. From a sleep perspective, which do you think may be more valuable?
Having more morning light helps with waking and alertness for daytime function. Light later in the day generally delays sleep and worsens sleep quality.
Standard time better matches the circadian clock to the solar day.
Are there additional factors that you think both legislators and the public should consider when it comes to weighing these different options?
Other factors at play are individual differences in circadian rhythm and chronotypes. For example, evening chronotypes generally are more affected by spring forward, according to a 2025 systematic review, getting less sleep, poorer sleep quality, and increased sleepiness in the spring.
The latitude and longitudinal position of a community within a time zone should also be considered. Other variables include interactions between urban and rural communities, age, behavioral patterns, and disease-specific effects with sleep.
