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A new survey from the American Academy of Sleep Medicine found that nearly 40 percent of people are sleep-deprived the Monday after the Super Bowl. Anna Bizon / Getty Images
- Last year, an estimated 14 million people were planning to take off work the day after the Super Bowl on what's become the most famous sick day of the year: #SuperSickMonday.
- A new survey finds that 40 percent of people say they're sleep-deprived the day after the Super Bowl.
- Even just one night of sleep deprivation can take a toll on your physical and mental health.
A new survey from the American Academy of Sleep Medicine (AASM) found nearly 40 percent of people are sleep-deprived the Monday after the Super Bowl.
<p>The game itself starts at 6:30 p.m. EST and can go well into the night. Most Super Bowls usually last around <a href="https://www.theverge.com/2017/2/4/14403598/how-long-is-the-super-bowl" target="_blank">3 hours and 45 minutes</a>, assuming the game doesn't go into overtime and there are no major costume malfunctions during the halftime show.</p><p>The whole shebang should wrap up at around 10:15 p.m. EST.</p><p>But many people keep the party going long after the winning team takes home the Vince Lombardi Trophy and end up getting a choppy night of sleep.</p><p>Last year, an estimated <a href="https://www.multivu.com/players/English/8254451-mucinex-supersickmonday/" target="_blank">14 million people</a> were planning to take off work the following day on what's become the most famous sick day of the year: #SuperSickMonday.</p><p>In fact, a survey from last year found that <a href="https://www.businessnewsdaily.com/11258-super-bowl-fever-employee-truancy.html" target="_blank">32 percent</a> of workers want the Monday after the Super Bowl to be declared a national holiday.</p><p>And a <a href="https://time.com/5771417/super-bowl-saturday/" target="_blank">16-year-old</a> in New York recently started <a href="https://www.change.org/p/nfl-change-the-superbowl-to-saturday" target="_blank">a petition</a> to move the Super Bowl to Saturday since so many people end up staying up late to watch the game.</p>
How much will one night of little sleep hurt you?
<p>Skimping out on sleep never feels good.</p><p>Sure, you might feel more grumpy than usual, but sleep deprivation — even just after one night — can take a toll on your <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5449130/" target="_blank">physical and mental health</a>.</p><p>"Even one night of missed sleep can cause irritability, dark circles, or puffy eyes (since missing a night of sleep can cause fluid to accumulate under your eyes), feeling forgetful the next day, or having slower reaction times, which can lead to making mistakes," said <a href="https://www.yalemedicine.org/doctors/lynelle_schneeberg/" target="_blank">Dr. Lynelle Schneeberg</a>, a sleep psychologist at Yale Medicine and author of "Become Your Child's Sleep Coach."</p><p>It can affect your judgment and mood and also up your risk for an accident or injury, according to <a href="http://healthysleep.med.harvard.edu/healthy/matters/consequences" target="_blank">Harvard Medical School</a>.</p><p>This is especially true for those driving while feeling drowsy. The Institute of Medicine estimates that drowsy driving is the cause of <a href="https://www.ncbi.nlm.nih.gov/pubmed/20669438" target="_blank">20 percent</a> of all motor vehicle crashes.</p><p>In the workplace, a lack of sleep can lead to <a href="http://healthysleep.med.harvard.edu/healthy/matters/consequences/sleep-performance-and-public-safety" target="_blank">impaired productivity and focus</a>. You're also more likely to feel stressed out, as fragmented sleep affects the stress hormones that control your ability to function.</p><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5449130/" target="_blank">Research</a> has also found it can worsen the symptoms of any underlying medical conditions.</p><p>But how much you'll feel these effects really comes down to how healthy you've been in the days leading up to the Super Bowl, according to <a href="https://med.nyu.edu/faculty/rebecca-j-scott" target="_blank">Rebecca Scott</a>, PhD, an assistant professor of neurology and sleep medicine specialist at NYU Langone Health.</p><p>"The better rested one is going into the shorter night of sleep, the less they will feel any impact," Scott told Healthline.</p><p>Humans are designed to be able to handle a night or two of less sleep without any major consequences, she adds. It's when it builds up that our health really starts to go downhill.</p>Alcohol and fatty foods can make it worse
<p>The Super Bowl is often synonymous with a night of <a href="https://www.ecowatch.com/tag/drinking">drinking</a> <a href="https://www.ecowatch.com/tag/beer" rel="noopener noreferrer">beer</a> and eating unhealthy, fatty foods — two things that can further impair a good night's sleep.</p><p>Alcohol prevents us from getting into a restorative, deep sleep, which is necessary for learning, memory retention, and cognitive functioning.</p><p>"Although one might fall asleep more easily after having alcohol, alcohol prolongs the amount of time it takes to fall into a dream, reduces the overall amount of dream sleep across a night, and can result in several brief awakenings as we metabolize the sugar in the alcohol," Scott said.</p><p>In addition, it's harder for the stomach to digest fattier foods. "These foods can cause indigestion or stomach upsets, which can worsen sleep, of course," Schneeberg said.</p>Here’s how to avoid #SuperSickMonday
<p>Unless you've been pulling all-nighters for days in a row, one night of little sleep won't do much damage. Scott says you should take the night and enjoy yourself.</p><p>"We often put work and responsibilities first, so give yourself permission to take an evening off without guilt," Scott said.</p><p>There are some strategies for reducing your chances of feeling completely miserable the next day.</p><p>First, do your best to have healthy sleep habits for the 2 days before and after the Super Bowl. Aim for around 8 hours of sleep, avoid caffeine in the late afternoons, and make sure you're well hydrated.</p><p>"One missed night of sleep is not usually a significant problem as long as you get back on track the very next night," Schneeberg said.</p><p>If you're already running low on sleep and expect to feel even worse the Monday after the Super Bowl, Scott says to be patient with yourself.</p><p>"Know that you might have a harder time focusing or be a bit more irritable than usual, and plan around that to the extent you can," Scott said.</p><p>Sleep deprivation symptoms tend to be worse in the afternoon — between 1 p.m. and 4 p.m. — so maybe avoid big activities in that window.</p><p>As long as the Super Bowl is on a Sunday and the day after isn't a national holiday, the best you can do is take care of yourself in the days leading up to the big game and set an earlier bedtime the night after.</p>The bottom line
<p>A new survey from the American Academy of Sleep Medicine found that nearly 40 percent of people are sleep-deprived the Monday after the Super Bowl.</p><p>Even just one night of sleep deprivation can take a toll on your physical and <a href="https://www.ecowatch.com/tag/mental-health">mental health</a>.</p><p>But how much you feel those effects really boils down to how healthy you've been in the days before and after the Super Bowl.</p>From Your Site Articles
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Take a Nap or Two Every Week. Your Heart Will Thank You, New Study Says
11 September 2019
Health + Wellness
Catherine Delahaye / The Image Bank / Getty Images Plus
If you're feeling that mid-afternoon sluggishness, it may help to give into temptation and doze off for a little while. Just don't do it too often.
<p>That's the key findings from a new <a href="https://heart.bmj.com/content/early/2019/08/16/heartjnl-2019-314999" target="_blank">study</a> published in the BMJ publication <a href="https://heart.bmj.com/content/early/2019/08/16/heartjnl-2019-314999" target="_blank">Heart</a>. The study concluded that a daytime nap once or twice a week might reduce the risk of cardiovascular events, such as heart attacks, strokes and heart failure by half.</p>
<p>The research, which was published on Monday, followed more than 3,400 adults aged 35 to 75 of Lausanne, Switzerland for an average of five years. While 58 percent of the people in the study said they did not nap at all, nearly 20 percent said they took a nap once or twice a week. The rest napped more frequently.</p><p>"We looked at healthy adults and found that people who take occasional naps — once or twice a week — had a lower risk for cardiovascular disease compared to people who were not napping at all," said Nadine Häusler, an internist at University Hospital of Lausanne, and lead author of the new research, as <a href="https://www.nbcnews.com/health/heart-health/1-2-naps-week-may-help-keep-your-heart-healthy-n1051376" target="_blank">NBC News</a> reported.</p><p>How long people napped for did not seem to matter. Instead, it was the nap frequency that was the largest determinant of the outcomes.</p><p>The one to two naps per week seemed to be the sweet spot for cardiovascular outcomes. More frequent naps did not have the same pronounced effect.</p>Sleep deprivation is a known risk factor for conditions including obesity, diabetes, high blood pressure, stroke, heart disease and mental distress, according to the <a href="https://www.cdc.gov/media/releases/2016/p0215-enough-sleep.html" target="_blank">U.S. Centers for Disease Control and Prevention</a>. Therefore, a nap's ability to replace lost nighttime sleep may make them a heart healthy habit, as <a href="https://time.com/5672111/naps-heart-health-study/" target="_blank">Time</a> reported.
<p>But, before you decide to skip work this afternoon and jump back into bed, there in an important caveat. In an editorial that appears next to the study, Dr. Yue Leng and Dr. Kristine Yaffe of the University of California San Francisco point out that research in this area is constrained by the absence of a gold standard for defining and measuring naps, making it "premature to conclude on the appropriateness of napping for maintaining optimal heart health," according to a BMJ statement in <a href="https://www.sciencedaily.com/releases/2019/09/190909193219.htm" target="_blank">Science Daily</a>.</p><p>However, they do conclude their editorial, "The study of napping is a challenging but also a promising field with potentially significant public health implications. While there remain more questions than answers, it is time to start unveiling the power of naps for a supercharged heart."</p><p>It may also be that people who have one or two naps a week just have healthier and organized lifestyles.</p><p>"This means the former pattern of occasional napping is intentional and the latter of more regular napping likely represents sub-clinical illness linked to poorer lifestyle. This would then explain the differential risks," said Naveed Sattar, Professor of Metabolic Medicine at the University of Glasgow, as <a href="https://www.cnn.com/2019/09/10/health/nap-heart-health-wellness-intl-scli/index.html" target="_blank">CNN</a> reported.</p><p>Sattar was not sold on the conclusions of the study. Instead, as <a href="https://www.cnn.com/2019/09/10/health/nap-heart-health-wellness-intl-scli/index.html" target="_blank">CNN</a> reported, he said, "For now, [it is] far better to aim for regular good night's sleep and to follow usual lifestyle advice of good diets and decent activity levels."</p>
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A considerable portion of the population sleeps past sunrise. aphrodite74 / E+ / Getty Images
By Steve Calandrillo
In my research on daylight saving time, I have found that Americans don't like it when Congress messes with their clocks.
In an effort to avoid the biannual clock switch in spring and fall, some well-intended critics of DST have made the mistake of suggesting that the abolition of DST – and a return to permanent standard time – would benefit society. In other words, the U.S. would never "spring forward" or "fall back."
<p>
They are wrong. DST saves lives and energy and prevents crime. Not surprisingly, then, politicians <a href="https://www.krem.com/article/news/politics/washington-bill-proposes-year-round-daylight-saving-time/293-e6d4c3c1-1471-47a0-b2d8-585cb9bace13" target="_blank">in Washington</a>, <a href="https://www.theverge.com/2018/11/7/18071898/california-permanent-daylight-saving-time" target="_blank">California</a> and <a href="https://www.orlandosentinel.com/news/politics/political-pulse/os-daylight-saving-law-20180703-story.html" target="_blank">Florida</a> are now proposing to move to DST year-round.
</p><p>
Congress should seize on this momentum to move the entire country to year-round DST. In other words, turn all clocks forward permanently. If it did so, I see five ways that Americans' lives would immediately improve.</p><p class="shortcode-media shortcode-media-youtube">
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="87a595c943193f252a9b11f919271d67"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/br0NW9ufUUw?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
<small class="image-media media-caption" placeholder="add caption...">Daylight Saving Time - How Is This Still A Thing?: Last Week Tonight with John Oliver (HBO)</small>
<small class="image-media media-photo-credit" placeholder="add photo credit...">
<a href="https://youtu.be/br0NW9ufUUw" target="_blank">youtu.be</a>
</small>
</p><h2>1. Lives would be saved.<br></h2><p>
Simply put, darkness kills – and darkness in the evening is far deadlier than darkness in the morning.
</p><p>
The evening rush hour is twice as fatal as the morning for various reasons: <a href="https://dx.doi.org/10.1136%2Fip.2005.011056" target="_blank">Far more people are on the road</a>, more alcohol is in drivers' bloodstreams, people are hurrying to get home and more children are enjoying <a href="http://commdocs.house.gov/committees/science/hsy73325.000/hsy73325_0.HTM" target="_blank">outdoor, unsupervised play</a>. Fatal vehicle-on-pedestrian crashes <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1615292/" target="_blank">increase threefold</a> when the sun goes down.
</p><p>
DST brings an extra hour of sunlight into the evening to mitigate those risks. Standard time has precisely the opposite impact, by moving sunlight into the morning.
</p><p>
A meta-study by Rutgers researchers demonstrated that <a href="https://www.ncbi.nlm.nih.gov/pubmed/15003579" target="_blank">343 lives per year</a> could be saved by moving to year-round DST. The opposite effect would occur if the U.S. imposed year-round standard time.
</p><h2>2. Crime would decrease.</h2><p>
Darkness is also a friend of crime. Moving sunlight into the evening hours has a far greater impact on the prevention of crime than it does in the morning. This is especially true for <a href="https://www.ojjdp.gov/ojstatbb/offenders/qa03401.asp?qaDate=2016" target="_blank">crimes by juveniles</a>, which peak in the after-school and early evening hours.
</p><p>
Criminals strongly prefer to do their work in the darkness of evening and night. <a href="https://doi.org/10.1016/S0169-2070(03)00093-1" target="_blank">Crime rates are lower</a> by 30 percent in the morning to afternoon hours, even when those morning hours occur before sunrise, when it's still dark.
</p><p>
A 2013 British study found that improved lighting in the evening hours could <a href="http://library.college.police.uk/docs/what-works/What-works-briefing-improved-street-lighting-2013.pdf" target="_blank">reduce the crime rate by up to 20 percent</a>.
</p><h2>3. Energy would be saved.</h2><p>
Many people don't know that the <a href="http://wakeforestlawreview.com/2008/01/time-well-spent-an-economic-analysis-of-daylight-saving-time-legislation/" target="_blank">original justification for the creation of DST</a> was to save energy, initially during World War I and II and then later during the 1973 OPEC oil crisis. When the sun is out later in the evening, peak energy loads are reduced.
</p><p>
Virtually everyone in our society is awake and using energy in the early evening hours when the sun sets. But a considerable portion of the population is still asleep at sunrise, resulting in significantly less demand for energy then.
</p><p>
Having more sun in the evening requires not just less electricity to provide lighting, but <a href="https://www.energy.ca.gov/reports/2001-05-23_400-01-013.PDF" target="_blank">reduces the amount of oil and gas required to heat homes and businesses</a> when people need that energy most. Under standard time, the sun rises earlier, reducing morning energy consumption, but only half of Americans are awake to be able to use the sun.
</p><p>
This rationale motivated some in California to recommend permanent DST a decade ago, when the state experienced recurrent electricity shortages and rolling brown-outs. Officials at the California Energy Commission estimated that <a href="https://www.energy.ca.gov/reports/2001-05-23_400-01-013.PDF" target="_blank">3.4 percent of California's winter energy usage</a> could be saved by moving to year-round DST.
</p><p>
Similarly, DST resulted in 150,000 barrels of oil saved by the U.S. in 1973, which helped combat the effect of OPEC's oil embargo.
</p><h2>4. Avoiding clock switches improves sleep.</h2><p>
Critics of DST are correct about one thing: The biannual clock switch is bad for health and welfare.
</p><p>
It wreaks havoc with people's sleep cycles. Heart attacks <a href="https://healthblog.uofmhealth.org/heart-health/why-daylight-saving-time-could-increase-your-heart-attack-risk" target="_blank">increase 24 percent</a> in the week after the U.S. "springs forward" in March. There's even an uptick during the week in November when the clocks "fall back."
</p><p>
If that's not bad enough, a study from 2000 shows that the major financial market indexes NYSE, AMEX and NASDAQ <a href="https://www.jstor.org/stable/117321?seq=1#metadata_info_tab_contents" target="_blank">average negative returns</a> on the Monday trading day following both clock switches, presumably because of disrupted sleep cycles.
</p><h2>5. Recreation and commerce flourish in the sun.</h2><p>
Finally, recreation and commerce flourish in daylight and are hampered by evening darkness.
</p><p>
Americans are <a href="https://qz.com/1120488/daylight-saving-time-as-americans-know-it-was-instituted-by-corporate-lobbies-not-farmers/" target="_blank">less willing to go out and shop in the dark</a>, and it's not very easy to catch a baseball in darkness either. These activities are far more prevalent in the early evening than they are in the early morning hours, so sunlight is not nearly as helpful then.
</p><p>
Not surprisingly, the U.S. Chamber of Commerce as well as most outdoor recreational interests <a href="https://www.washingtonpost.com/opinions/five-myths-about-daylight-saving-time/2015/03/06/970092d4-c2c1-11e4-9271-610273846239_story.html?utm_term=.d446e4c4cf34" target="_blank">favors extended DST</a>.
</p><p>
Research shows that sunlight is far more important to Americans' health, efficiency and safety in the early evening than it is in the early morning. That's not to say there aren't downsides to DST – notably, an extra hour of morning darkness. But I believe the advantages of extended DST far outweigh those of standard time. It is past time that the U.S. sets the clocks forward forever, and never has to switch them again.</p><p class="shortcode-media shortcode-media-twitter_embed">
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</p><p><em>Steve Calandrillo is the </em><em>Jeffrey & Susan Brotman Professor of Law at the University of Washington.<br></em><em>Disclosure statement: Steve Calandrillo does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond his academic appointment.</em></p><p>
<em>Reposted with permission from our media associate <a href="https://theconversation.com/5-ways-life-would-be-better-if-it-were-always-daylight-saving-time-111506" target="_blank">The Conversation</a>.</em>
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Salting streets in Milwaukee. Michael Pereckas / CC BY-SA
By Jennifer Marie Hurley
Every winter, local governments across the U.S. apply millions of tons of road salt to keep streets navigable during snow and ice storms. Runoff from melting snow carries road salt into streams and lakes, and causes many bodies of water to have extraordinarily high salinity.
At Rensselaer Polytechnic Institute, my colleague Rick Relyea and his lab are working to quantify how increases in salinity affect ecosystems. Not surprisingly, they have found that high salinity has negative impacts on many species. They have also discovered that some species have the ability to cope with these increases in salinity.
<p>
But this ability comes at a price. In a recent study, Rick and I analyzed how a common species of zooplankton, <em>Daphnia</em> <em>pulex</em>, adapts to increasing levels of road salt. We found that this exposure affected an important biological rhythm: The circadian clock, which may govern <em>Daphnia</em>'s feeding and predation avoidance behaviors. Since many fish prey on <em>Daphnia</em>, this effect could have ripples throughout entire ecosystems. Our work also raises questions about whether salt, or other <a href="https://www.ecowatch.com/tag/toxics">environmental pollutants</a>, could have similar impacts on the human circadian clock.
</p><p class="shortcode-media shortcode-media-rebelmouse-image">
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xNzA0Mzc1Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTU5MTU3ODU2OH0.M6XY9NqWC5wy4say1iqdtM4x1PCMhTeAlQMrdg4Uq8k/img.jpg?width=980" id="b9120" class="rm-shortcode" data-rm-shortcode-id="ebb29a830f7bcc881d16fcad866b7e5a" data-rm-shortcode-name="rebelmouse-image">
<small class="image-media media-caption" placeholder="add caption...">Daphnia pulex</small><small class="image-media media-photo-credit" placeholder="add photo credit...">Brian Mattes, CC BY-ND</small>
</p><p>
<strong>Daily biological rhythms and the circadian clock<br>
</strong></p><p>
In studying how road salt affects aquatic ecosystems, the Relyea lab showed that <em>Daphnia</em> <em>pulex</em> can <a href="https://doi.org/10.1016/j.envpol.2016.12.024" target="_blank">adapt to handle moderate exposures</a> in as little as two and a half months. These levels ranged from 15 milligrams of chloride (a building block of salt) per liter of water to a high of 1,000 milligrams per liter—a level found in highly contaminated lakes in North America.
</p><p>
However, an organism's ability to adapt to something in its environment can also be accompanied by negative trade-offs. My lab's collaboration with Rick's began in an effort to identify these trade-offs in salt-adapted <em>Daphnia</em>.
</p><p>
In <a href="http://homepages.rpi.edu/~hurlej2/" target="_blank">my lab</a>, we study how our circadian rhythms <a href="https://doi.org/10.1016/bs.mie.2014.10.009" target="_blank">allow us to keep track of time</a>. We investigate how the molecules in our cells work together to tick like a clock. These circadian rhythms allow an organism to anticipate 24-hour oscillations in its environment, such as changes from light (daytime) to dark (nighttime), and are <a href="https://doi.org/10.1177/074873098129000309" target="_blank">essential to an organism's fitness</a>.
</p><p>
Rick and I hypothesized that adaptation to high salinity could disrupt <em>Daphnia's</em> circadian rhythms based on recent evidence showing that other environmental contaminants can disrupt <a href="https://doi.org/10.1016/j.aquatox.2016.11.007" target="_blank">circadian behavior</a>. One important behavior in <em>Daphnia</em> that <a href="http://dx.doi.org/10.1016/j.cub.2017.06.025" target="_blank">may be controlled by the circadian clock</a> is the <a href="http://www.cell.com/current-biology/pdf/S0960-9822(14)01067-7.pdf" target="_blank">diel vertical migration</a>—the largest daily biomass migration on Earth, which occurs in <a href="http://www.ecowatch.com/tag/oceans">oceans</a>, bays and lakes. Plankton and fish migrate down to deeper water during the day to avoid predators and sun damage, and back up toward the surface at night to feed.
</p><p class="shortcode-media shortcode-media-rebelmouse-image">
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xNzA0Mzc2Mi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0MDc5MTMxOH0.6dtVKxz8U43B95hiHJlaE9wZmlWaSLRqabBYiJxFT6o/img.jpg?width=980" id="48e3f" class="rm-shortcode" data-rm-shortcode-id="b9eaa9ca2858f843e617bc5c3087dfbc" data-rm-shortcode-name="rebelmouse-image">
<small class="image-media media-caption" placeholder="add caption...">Echogram illustrating the ascending and descending phases of diel vertical migration, in which organisms ascend and descend through the water column. The color scale reflects acoustic scattering by concentrations of organisms at different depths. </small><small class="image-media media-photo-credit" placeholder="add photo credit...">DEEP SEARCH—BOEM, USGS, NOAA</small>
</p><p>
Given what we know about circadian function, it would be logical to assume that exposure to pollution would not affect an organism's circadian rhythms. While circadian clocks can incorporate environmental information to tell the time of day, they are <a href="https://doi.org/10.1007/978-3-642-45218-5_6" target="_blank">heavily buffered against most environmental effects</a>.<br>
</p><p>
To understand the importance of this buffering, imagine that the timing of an organism's day length responded to environmental temperature. Heat speeds up molecular reactions, so on hot days the organism's 24-hour rhythm could become 20 hours, and on cold days it might become 28 hours. In essence, the organism would have a thermometer, not a clock.
</p><p><strong>Adaptation to pollution affects key circadian genes</strong></p><p>
To determine whether clock disruption is a trade-off to pollutant adaptation, we first had to establish that <em>Daphnia</em> is governed by a circadian clock. To do this, we identified genes in <em>Daphnia</em> that are similar to two genes, known as <em>period</em> and <em>clock</em>, in an organism that serves as a circadian model system: <em>Drosophila melanogaster</em>, the common fruit fly.
</p><p>
We tracked the levels of <em>period</em> and <em>clock</em> in <em>Daphnia</em>, keeping the organisms in constant darkness to ensure that a light stimulus did not affect these levels. Our data showed that the levels of <em>period</em> and <em>clock </em>varied over time with a 24-hour rhythm—a clear indication that <em>Daphnia </em>have a functional circadian clock.
</p><p>
We also tracked the same genes in populations of <em>Daphnia</em> that had adapted to increased salinity. Much to my surprise, we discovered that the daily variation of <em>period</em> and <em>clock</em> levels deteriorated directly with <a href="http://dx.doi.org/10.1002/ece3.3490" target="_blank">the level of salinity the <em>Daphnia</em> were adapted to</a>. In other words, as <em>Daphnia </em>adapted to higher salinity levels, they showed less variation in the levels of <em>period</em> and <em>clock</em> over the day. This demonstrated that <em>Daphnia</em>'s clock is indeed affected by pollutant exposure.
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We currently don't understand what causes this effect, but the relationship between salinity levels and decreased variation in the levels of <em>period</em> and <em>clock</em> offers a clue. We know that exposure to pollutants causes Daphnia to undergo <a href="http://onlinelibrary.wiley.com/doi/10.1002/etc.2887/abstract" target="_blank">epigenetic regulation</a>—chemical changes that affect the function of their genes, without altering their DNA. And epigenetic changes often show a gradual response, becoming more pronounced as the causal factor increases. Therefore, it is likely that high salinity is inducing chemical changes through these epigenetic mechanisms in <em>Daphnia</em> to suppress the function of its circadian clock.<br>
</p><p><strong>The broad effects of circadian clock disruptions</strong></p><p>
We know that environmental conditions can affect what the clock regulates in many species. For example, changing the sugar that the fungus <em>Neurospora crassa</em> grows on <a href="http://dx.doi.org/10.1073/pnas.1418963111" target="_blank">changes which behaviors the clock regulates</a>. But to our knowledge, this study is the first to show that genes of an organism's core clock can be directly impacted by adapting to an environmental contaminant. Our finding suggests that just as the gears of a mechanical clock can rust over time, the circadian clock can be permanently impacted by environmental exposure.
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This research has important implications. First, if <em>Daphnia's</em> circadian clock regulates its participation in the diel vertical migration, then disrupting the clock could mean that <em>Daphnia</em> do not migrate in the water column. <em>Daphnia</em> are key consumers of <a href="http://www.ecowatch.com/tag/algae">algae</a> and a food source for many fish, so disrupting their circadian rhythms <a href="http://dx.doi.org/10.1073/pnas.1600366113" target="_blank">could affect entire ecosystems</a>.
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Second, our findings indicate that environmental pollution may have broader effects on humans than previously understood. The genes and processes in <em>Daphnia's</em> clock are very similar to those that regulate the clock in humans. Our circadian rhythms control genes that create cellular oscillations affecting cell function, division and growth, along with physiological parameters such as body temperature and immune responses.
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<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xNzA0Mzc3Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyOTY5Nzc3Mn0.S6YYPWYdhtLUOWvVk7v6lPv3z1gp1ZMuV_ggjMFo9Ic/img.jpg?width=980" id="32423" class="rm-shortcode" data-rm-shortcode-id="7534b85ae6fd97335865781f898f26fd" data-rm-shortcode-name="rebelmouse-image">
<small class="image-media media-caption" placeholder="add caption...">The human circadian clock regulates the cycles of many bodily functions.</small><small class="image-media media-photo-credit" placeholder="add photo credit...">NIH</small></p><p>
When these rhythms are disrupted in humans, we see increased rates of <a href="https://doi.org/10.1016/B978-0-12-396971-2.00010-5" target="_blank">cancer, diabetes, obesity, heart disease, depression and many other diseases</a>. Our work suggests that exposure to environmental pollutants may be depressing the function of human clocks, which could lead to increased rates of disease.<br>
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We are continuing our work by studying how the disruption of <em>Daphnia</em>'s clock affects its participation in the diel vertical migration. We are also working to determine the underlying causes of these changes, to establish whether and how this could happen in the human brain. The impacts we have found in <em>Daphnia</em> show that even a simple substance such as salt can have extremely complex effects on living organisms.
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<em>Reposted with permission from our media associate <a href="https://theconversation.com/can-road-salt-and-other-pollutants-disrupt-our-circadian-rhythms-89211" target="_blank">The Conversation</a>.</em>
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