The Dark Side of Switching to Daylight Saving Time

How Springing Forward Affects Your Sleep and Health

I’m generally a glass half full gal, so I try to look for the good in all situations. But I struggle to find the good in the semiannual time change. I abhor a thief—particularly one that steals my time. So, count me among those who detest the “spring forward” weekend when we switch to Daylight Saving Time (DST). Losing an hour of my valuable time is a major reason I loathe this practice; but other reasons include sleep disruptions and negative health consequences. It’s almost a week since the switch to DST, and I’m still feeling the effects.

Sleep Schedule Disruptions and Health Impacts

DST messes up my sleep schedule, which is not a small thing. I do what I reasonably can to live a long and healthy life, and sleep is a major contributor to health and longevity. Indeed, quality sleep and adherence to a regular sleep pattern has been associated with longevity and better health into old age.

So, I try to be consistent with my sleep schedule, which means I get out of bed in the morning at the same time, and go to bed every night at the same time—even the weekends. This practice is an important component of good “sleep hygiene,” which is something all of us should strive for. Research has shown that people with a consistent sleep schedule enjoy better sleep quality because it influences our circadian rhythm (internal clock) and reinforces our body’s natural sleep-wake cycle. Disrupting the circadian rhythm by having an inconsistent sleep cycle confuses our brains, and no one—especially not me—wants to have a confused brain.

My brain has definitely been confused! The first day of the switch was probably the hardest, and seemed to go by lightening fast. Suddenly it was time to go to bed and it felt like I’d just gotten up. My internal clock thought it was an hour earlier and told me I had another hour before bedtime. I was tempted to listen to my internal clock, but I knew I’d regret it if I did. After all, I had to get up regardless of what my internal clock said.

This time discombobulation extended beyond that first Sunday. For the past several days, when I looked at the clock and saw the time, it felt wrong. Unfortunately, my internal clock must defer to DST. One thing was very clear to me; the time on the clock didn’t sync with my internal clock. Another thing I’m sure of; no one cares. If I’m an hour late to a meeting, the excuse that, “My circadian rhythm told me it’s an hour earlier, so I’m not really late,” is not going to fly. By Wednesday I’d stopped the time charade and just accepted that my internal clock would take several more days to reset.

If like me you’ve felt a little off since the switch to DST, that may be because in addition to the fact that sticking to a set sleep and wake time is important for your brain, it also benefits your overall physical health and could extend your life. Recently, a study revealed that better sleep consistency was associated with a significantly lower risk for mortality. Those with the most consistent sleep schedule had a 30% lower mortality risk and a 38% lower cardiometabolic (common and often preventable chronic diseases that affect your cardiovascular system) mortality risk, marking sleep consistency as a more important factor than sleep duration for health.

Sleep irregularity has a detrimental effect on your long-term physical health. A 2023 study from the American Heart Association found that people who slept varying amounts each night and kept unpredictable bedtime schedules experienced an increased risk of hardened arteries. It echoed the findings of a 2019 report that found that inconsistent sleep schedules not only put you at a higher risk of hypertension and high cholesterol, but also increase your risk of experiencing a metabolic issue (like diabetes) by 27%.

A regular sleep schedule may even affect how long you live, according to a 2014 study on adults between 85 and 105 years old. It found that the oldest participants who maintained a strict bedtime and wake-up time had better measurements of cardiovascular health than other adults in the study, which may be a contributing factor to their longevity. For a deeper dive into sleep-related health and wellness issues, as well as ways to improve your sleep, check out Catherine Darley’s

Be A Skilled Sleeper

Substack.

Your body’s circadian clock responds to light as a signal to be awake, and dark as a signal to fall asleep. DST means there’s no sunlight in the early morning when I walk. Before DST, I got sun exposure during my morning walk, which has a powerful effect on the circadian clock, sleep, and alertness. Now I’m walking in the dark. My circadian clock is not receiving the light message that it’s time to wake up. Instead, the morning darkness signals that I should still be sleeping. So if you’ve been finding it harder to get out of bed this week, one reason may be that it’s still dark. Sun exposure within an hour of waking actually helps you sleep better at night and helps you to be more alert throughout the day. It’s no wonder I’ve been feeling lethargic since the switch.

A Brief History of DST

Why can’t the time just stay the same year-round? I wanted to know the origins of DST, so I did a some research, which I found enlightening (no pun intended). I thought that DST and the switching back and forth started during the energy crisis in the 1970s, but I thought wrong.

• The United States introduced Daylight Saving Time as a fuel conservation effort in 1918 during World War I (1914-1918) and adopted a year-round Daylight Saving Time policy during World War II for similar reasons. The idea was that Americans wouldn’t have to turn on their lights so early in the day, thereby conserving energy.

• In 1966 the Uniform Time Act made it U.S. policy to observe six months of Daylight Saving Time and six months of Standard Time.

• During the energy crisis in 1973, Congress passed a law reinstituting year-round DST. This experiment was supposed to last two years, but due to widespread unpopularity and public outcry, in the fall of 1974 Congress reverted to the six month split between Standard Time and DST.

• The U.S. started observing seven months of Daylight Saving Time in 1986, and has been observing eight months from March to November since 2007. Recent efforts to make DST permanent have been unsuccessful.

The sentiment expressed by people I’ve talked to is, “Let’s just pick one time and go with it. No more switching back and forth.” I haven’t found anyone who really likes the switch. Some people like having sunlight into the evening, but I didn’t find anyone who liked the process of switching to DST. No one likes losing an hour, not to mention that it muddles our brains and has the potential to decrease our overall wellness and longevity. What are your thoughts on the switch to DST?