Daylight saving time causes sleep disruption
Q: I hate switching to and from daylight saving time every year. My husband says it's just a nuisance, but it messes up my sleep, and I think it's affecting my health. Haven't there been some studies about that? We're both interested in your answer.
A: You're far from alone in your feelings about being forced to either lose or gain an hour as daylight saving time begins and ends each year. The energy-saving origins of the idea have since been disproved, as studies show that the drop in lighting demands is offset by air conditioning use during the longer summer days. Meanwhile, as you are experiencing, the practice has been shown to lead to widespread sleep disruptions.
Numerous studies have linked the time shift to increases in workplace and automobile accidents, heart attacks, depression and sleep disorders. Considering all that we continue to learn about the close link between the functioning of our bodies, and the daily cycle of light and dark, these findings don't come as a complete surprise.
A large new study into the health effects of daylight saving time, published last June, analyzed health data from 150 million patients in the United States and 9 million patients in Sweden. In addition to the ill effects we already mentioned, the researchers reported that the semiannual time shift also played a role in increases in digestive disorders such as noninfective enteritis and colitis, complications related to pregnancy and childbirth, and autoimmune and inflammatory disease. Some of these showed a modest uptick of about 3%, while others, such as car accidents that resulted in injury, spiked up to 30% on the day of the shift into daylight saving time.
It's important to note that, depending on your personal work and life schedules, daylight saving time affects everyone differently. People who have to be at work at an early hour suddenly find themselves waking up and commuting in the dark. Younger kids are being sent to bed while the sun is still in the sky. Location plays a role, as well, with people living farther south less affected by the time shift. And while it's true we do adapt, the research continues to suggest that even just a 60-minute realignment can have real repercussions.
Meanwhile, unless you live in Hawaii or Arizona, which don't switch their clocks, there are a few steps you can take to try to reduce the degree of disruption. Sleep specialists suggest planning ahead. Several weeks before daylight saving time begins, start going to bed a few minutes earlier each night and waking up a few minutes earlier each morning. This helps ease you into the one-hour loss of time. Then, make it a point to expose yourself to early morning daylight when the sun does rise, which can help your body clock to adjust. Keep the rest of your schedule as regular as possible, including exercise and mealtimes, so your body isn't dealing with additional change and stress. These won't erase the challenges caused by that lost hour, but they may make adjusting a bit easier.
Q: I have a question I'm sure is on the minds of others, as well — where is the flu this year? All we are hearing about is COVID-19. Did the flu vaccine they gave work that well? Is no one getting the flu anymore?
A: You've asked an excellent question with a somewhat complex answer. The short version is that, yes, incidence of influenza infection has been markedly lower for the flu season thus far. We're seeing that in our own practices. As of the middle of February, we have not had a single case of influenza. To say that's unusual is an understatement.
Our experience is reflected in the numbers the Centers for Disease Control and Prevention use to track the course of influenza infection in the United States. In the last week of 2020, for example, only 1% of samples tested positive for influenza. Typical results at that time of year are in the 20% to 30% range. Global tracking data also mirror this trend.
A number of factors are playing a role in this year's surprising flu season numbers. An important one is the many mitigation measures we're all taking in the fight against COVID-19. These include social distancing, wearing a mask, vigilant hand-washing and cleaning high-touch surfaces. Environments that act as natural petri dishes for the spread of respiratory infections, such as offices and classrooms, are either severely restricted or completely shut down. Ditto for group activities such as concerts, sporting events, travel, dining, bars and other recreational activities.
In physically protecting ourselves and limiting our potential exposure to the airborne coronavirus, we're also shielding ourselves from the coughs and sneezes and surface contamination that spread the flu. The influenza virus, less transmissible than the coronavirus, is proving no match for these multiple layers of precautions.
The differences in tracking methods for COVID-19 and the flu are playing a role. With the coronavirus, the goal is to count every possible case in order to understand the trajectory of the pandemic. To that end, many millions of coronavirus tests have been administered, and all of the resulting data collected and logged. Statistics about the number of cases each flu season, by contrast, are estimates. These are arrived at by analyzing testing data collected from designated public health and clinical laboratories, and from a network of medical practices and hospitals.
It's also important to note that people aren't visiting the doctor as much as in pre-pandemic days. When they do seek medical care, the respiratory illness they're most concerned with is COVID-19, so that's the test they're most interested in getting. There's evidence that a number of people are opting to treat suspected flu-related illnesses at home, which also lowers the reported influenza numbers. However, influenza-related hospitalization rates, with just 155 lab-confirmed admissions from Oct. 1 to Jan. 30, bolster the idea that this year's flu season is unusually mild.
If mask-wearing and other physical precautions continue after the epidemic, then we may continue to see lower influenza rates in the future.
• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.