I can predict the future.
On Monday, March 13, 2023, more than any other day, significantly more people will suffer from heart attacks, or be involved in car accidents, in the United States and other parts of the world.
On Monday, March 13, 2023, people living in the United States, excepting those located in Hawaii and Arizona, will have advanced their clocks one hour. What began as an energy savings idea, proposed by Benjamin Franklin in the late 18th century, eventually became law in the United States in 1918.
By “springing forward” in March, people have an increase in daylight hours into the evenings, with expectations that people would enjoy more time out and about into the early evenings, that less energy would be needed in the evening, and that fewer hours of darkness would limit the dirty deeds of bad actors in our communities.
Alas, good ideas often have unintended consequences. When we lose an hour to implement Daylight Savings Time (DST), we lose an hour of sleep. Does one hour have an impact on our health? According to Matthew Walker, professor of neuroscience and psychology at the University of California Berkley, and author of bestselling book, “Why We Sleep,” the answer is yes. And the proof is in the results of an “experiment” governments run every year.
There is a global experiment that is performed on 1.6 billion people across 70 countries twice a year, and it’s called daylight savings time. Now in the Spring in the Northern Hemisphere, when we lose one hour of sleep, we actually see a subsequent 24% increase in relative heart attack rates the following day. Yet, in the Autumn, in the fall, when we gain an hour of sleep, we see a 24% reduction in heart attacks.
According to a study in Finland, strokes occur at a higher rate of 8% the first two days after moving the clock one hour later. In this article from the Diagnostic and Interventional Cardiology website, the president of the American Heart Association speculates that DST “has something to do with the disruption of the body’s internal clock, or its circadian rhythm.”
In other words, it’s not good to have our sleep interrupted or shortened. In addition to the risk to our heart, the hours and days after the loss of an hour of sleep impacts our mood, makes us grumpier. No kidding you say. Ah, but there are consequences to reporting to work on Monday after a crappy sleep.
In 2017, professors from the University of Washington and the University of Virginia published a study that concluded federal judges in the United States were likely to hand down harsher judgments in court proceedings held the Monday after daylight savings commences. They found that the average length of prison sentences were 5% longer on that particular day, compared to the Mondays prior or after the sleep-deprived Monday.
Who cares? You should. There is increasing and clearer evidence of the importance of sleep to our health.
Sleep expert Walker asks recommends that the average adult get between 7 to 9 hours a night. Getting fewer hours than that consistently is not healthy.
“What we certainly know from the evidence is that the number of people who can survive on, let’s say, less than six hours or five hours a night without showing any impairment, rounded to a whole number and expressed as a % of the population, is 0.”
In this video, Dr Charles Czeisler, Director of Sleep Medicine at Harvard Medical explains that ones ability to survive, literally, is diminished dramatically if we are driving while sleepy:
- One in five car crashes is the result of drowsy driving.
- Every month, about 56 million Americans admit that they’re having difficulty staying awake when they’re driving.
- About 8 million of them lose that struggle and actually fall asleep at the wheel. And that causes about a million crashes every year, 500,000 injuries every year.
- About 55,000 of those are debilitating injuries that leave people either quadriplegic or seriously injured in some way.
- And it causes nearly 7,000 deaths every year.
In the same video, Dr. Judith Owens, the Director of Sleep Medicine at Boston Children’s Hospital, says the consequences of poor sleep impacts the youth in particular, and may be related to the number one and number three causes of death for adolescents in the US: car accidents and suicide.
Motor vehicle crashes– two-thirds of accidental injury fatalities in adolescence are related to road crashes. And study after study has shown that adolescent drivers are more likely to report drowsy driving. And that is clearly a risk factor for becoming involved in car accidents.
And minority students were more likely to get insufficient sleep. 40% of the teens in the study who got six or less hours of sleep reported depression symptoms. And almost three times as many students getting less than six hours of sleep reported alcohol use in the past 30 days compared to those getting more than nine hours. So this risk taking, this emotional regulation, this poor decision making plays out in some very important health and safety outcomes.
The United States government has actually debated the necessity of changing the time twice a year. On March 15, 2022, the US Senate in fact passed legislation to put an end to clock-changing. However, the US House of Representatives also needs to approve of this legislation, which has yet to happen. If this law is eventually passed, the nation would have one more “Spring forward” in March – where days would be longer, and health risks will be greater for a few days – but no more “Fall backs” in November.
The grand experiment, at least in the US, may end soon.
But the evidence is clear.
You need your sleep.
Seven to nine hours a night.
Your life depends on it.
ARTICLE FAQS
1. Why does losing one hour of sleep for Daylight Savings Time matter?
Studies show that even a single lost hour raises health and safety risks. Heart attacks, strokes, car crashes, and workplace errors all increase in the days immediately after the spring clock change.
2. What does the research say about health impacts?
A large study found a 24% rise in heart attacks the day after clocks move forward, with a matching 24% drop when an hour of sleep is gained in the fall. Research in Finland also links the spring change to higher stroke risk.
3. How does sleep loss affect judgment and behavior?
Sleep-deprived people are more irritable and less able to regulate emotions. Research shows federal judges in the US issue sentences about 5% longer on the Monday after the spring change.
4. How is driving affected by poor sleep?
Drowsy driving is linked to about one in five crashes in the US each year. Roughly 7,000 people die annually in accidents caused by drivers who fall asleep at the wheel.
5. Why are teenagers especially at risk?
Lack of sleep among adolescents is associated with more car accidents, higher rates of depression, and increased risky behaviors such as alcohol use. Experts emphasize that teens need 8–10 hours of sleep, but many get far less.
6. How much sleep is considered healthy for adults?
Sleep experts recommend 7–9 hours each night. Fewer than six hours of consistent sleep leads to impairment, with essentially no segment of the population immune to the consequences.
