Ask people’s opinions about Daylight Savings Time (DST) and you will receive a variety of responses. Some love it, others dread it, some don’t care either way; however, one thing most will agree on is that they don’t look forward to that fateful weekend when we “lose an hour”. Humans are creatures of habit and changing clocks an hour forward (or back in the fall) can really mess with our routines.
We know that the human body uses daylight to synchronize to the environment. It’s so specific that people in different areas of the same time zone will adjust to their specific location. A large survey conducted in 2007 revealed that the timing of sleep on free days will naturally adjust to the dawn.
However, this does not occur during DST. The researchers continued that in a second study, they looked at timing of sleep and activities for 8 weeks around the transition to DST. Again, they found that the human body adjusts easily during standard time. Those who are part of the “night-owl” population tended to adjust somewhat easier than their early-riser “lark” counterparts for the fall change, but this was not a significant difference.
Across the board, adjustment to the timing of sleep and activity typically occurs within a week after the fall transition back to standard time. By contrast, the full transition after the spring change to DST can take as long as 5 weeks of gradual adjustment. There was a significant difference between the larks and owls after the spring change with larks tending to adjust their sleep time by about 40 minutes, and the owls failed to make the adjustment.
It appears that while the human body’s internal clock naturally advances from autumn to spring with the dawn, it stalls and remains in that time between spring and autumn.
It doesn’t sound like a great deal of time – 1 hour. However, this shift can have considerable effects on the human body. In an interview for an article posted on Health.com, Sandhya Kumar, MD, assistant professor of neurology and medical director of the Sleep Disorders Center at Wake Forest Baptist Medical Center in North Carolina states:
“With the spring time change, you essentially have to go to bed earlier and get up earlier, which is difficult for many of us to do…Most of us end up losing 40 to 50 minutes of sleep those first few days—and as a nation that’s significantly sleep deprived to begin with, even that little change can impact health.”
Generally, when the “Spring Forward” weekend occurs, many people feel like they have jet lag for a few days. Research shows that the change to DST in the spring can have significant effects on our health – and while a few are positive, generally speaking, it’s not for the good.
Researchers have investigated multiple facets of the impact the time change has on our health. For the spring time jump forward, the effects include not only the obvious disrupted sleep, but also increases in accidents, injuries, heart issues, strokes and even fertility. In a new study just published in June 2020, researchers state that while the majority of these increases are fairly small (only a few percentage points), “a considerable number of diseases exhibit an approximately ten percent relative risk increase” and they “estimate that each spring DST shift is associated with negative health effects–with 150,000 incidences in the US, and 880,000 globally.” Some of their findings for the effects of the Spring change to DST included:
- Decreased risk of a certain set of infectious and inflammatory diseases
- Increased risk of disorders involving the digestive system (such as noninfective enteritis and colitis). +3% for females over 60 and +6% in males under ten.
- Significant increased risk of complications related to pregnancy, childbirth, and puerperium (PCP)
- Significant increased risk of injuries of the head, wrist, and hand among children (0–10) and teenagers/young adults (11–20)
- Significant increased risk injuries to the lower torso or thorax among older adults (41 and older)
- Significant increased risk of immune disorders
- Significant increased risk of ischemic heart disease rates in males and females older than 60
- Possible increase in risk of urinary system-related renal failure
- Possible increase in risk of circulatory/cognition symptoms and signs
- Up to 9% increase in use of psychoactive substance use among males age 20 or above
- Those who were very young (0–10, or 11–20) or older patients with chronic diseases seemed to be the most affected by the time change.
Regarding the decrease in some infectious and immune diseases, authors surmise that the spring time shift could act as a “short-term stressor” and other research has demonstrated that a brief, mild stress event can actually enhance the immune system.
A 2017 study published in The Journal of Biological and Medical Rhythm Research looked at the impact the time change has on fertility. They conducted a retrospective cohort study in 1,654 autologous in vitro fertilization cycles (2009 to 2012). They discovered that while overall pregnancy rates (41.4%, 42.2%) and loss rates (15.5%, 17.1%), were comparable, there was a significantly higher rate of loss in spring when DST occurred within 21 days after embryo transfer (24.3%). This loss rate was even greater among patients with a history of prior spontaneous pregnancy loss (60.5%).
Similarly, researchers examined claims from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) database for the weeks immediately following fall and spring time changes that occurred between March 2010 and September 2013. They evaluated changes in admissions for cardiac patients undergoing percutaneous coronary intervention (PCI). They found that while the total per week remained fairly consistent, there was a marked difference in the daily rates. While the Tuesday following the fall transition off DST had a 21% reduction in the procedures, the Monday after Spring transition to DST was associated with a 24% increase! Heart attacks aren’t the only cardiovascular events that seem to be affected by changing to or from DST. A preliminary research paper presented at the 2016 American Academy of Neurology’s annual meeting reported that stroke rates in Finland increase by as much as 8% in the 2 days following a time change – in either direction. Older adults, and people with cancer were the most susceptible to this risk increase.
What do people do when they are sleep deprived from the change to DST? The internet is now available to many people even when they are at work. However, this easy access has at times, led to “cyberloafing” with people surfing the internet when they are supposed to be actually working. This leads to a loss of productivity for the company. According to a study in the Journal of Applied Psychology, cyberloafing behaviors dramatically increase nationwide after the spring transition to DST.
Some research suggests that teens may be especially sensitive to DST related sleep loss. With all the changes occurring in their body, they may have a harder time shifting their sleep patterns. A natural experiment design was used to evaluate baseline and post-DST sleep and vigilance among high school students. Results showed that students on average, slept 32 minutes LESS per night in the days following the spring transition to DST, leading to a cumulative sleep loss of 2h 42m. Additionally, vigilance was down significantly and daytime sleepiness was up. This combination led to longer reaction times and increased lapses. Not only is this concerning for athletics, but also for automobile accidents, since teens have less experience driving. Multiple studies report an increase in fatal automobile accidents following the spring time change.
Rest assured there are ways to handle the time change in order to minimize the negative effects.
- If your family’s schedule allows, start going to bed a little earlier and earlier each night leading up to the change.
- Get as much light as possible when you get up in the morning. The light is a large part of what triggers your body to adjust. If natural sunlight isn’t possible, consider using a light box or dawn simulator may help you trick your internal clock into believing that it’s time to get moving.
- Exercise in the morning. This gets you up and moving, exposes you to light and raises your body temperature, all of which are great ways to help your body wake up.
- Don’t rely on caffeine to get you through the transition. That boost will be followed by a slump, potentially setting you back further than you were when you started.
- Be careful about napping. While a brief nap can help some people get a 2nd wind to round out the day, it can cause others to have difficulty falling asleep or staying asleep come nightfall. Be realistic with yourself and about if that nap will help you or not.
If you are having trouble sleeping or if you feel like your body is not adapting to the time change or to other aspects of your daily life, talk to your doctor of chiropractic at your next visit. Whether you need an adjustment to help your body function optimally or need help knowing what type of pillow or mattress is best suited for you, your chiropractor is trained and knowledgeable in helping you sleep better and stay healthy. Additionally, your doctor of chiropractic can provide a referral to another health care provider, if appropriate.
Knowing how to approach our annual leap into Spring and being aware of the ways DST impacts our sleep, habits and mood, is the best defense against the negative effects the time change can have on our wellbeing. Don’t let DST keep you from springing forward to better health!
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