How Daylight Saving Time Disrupts Sleep and Impacts Health

Except for a few locations in the U.S., most of the country follows seasonal Daylight Saving Time (DST). As a result, the majority of us are challenged to reset our master clocks one hour every spring and fall, either losing or gaining an hour of sleep. While an hour may not sound like a lot, those 60 minutes can have a big impact on our physical and emotional well-being. And we don't mean just one grumpy day.

Research has shown the following disturbing trends in the week following the time change:

• a 24% increased risk of heart attacks
• an 8% increased risk of stroke
• a 6% spike in fatal car accidents
• an 11% spike in depressive episodes

How Does Daylight Saving Time Impact Our Internal Clock?

According to Dr. Karin Johnson, the Medical Director for Baystate Regional Sleep Medicine Program, adequate and quality sleep is essential to our emotional and physical health. "When sleep cycles are interrupted, be it to a baby in the house or Daylight Saving Time, it has a ripple effect on our overall well-being," she says.

"Our bodies have an innate master clock, or circadian rhythm, that cycles us through daily periods of sleep and wakefulness. Light receptors in our eyes essentially set the clock each day, taking cues from sunlight. When it begins to get bright, we wake up. When it starts to grow dark, we grow sleepy. Our clocks and bodies are basically wired to be aligned with the sun."

In addition to triggering periods sleep and wakefulness, the master clock works to keep other bodily functions in check. These include:

• Heart rate
• Blood pressure
• Metabolism and energy levels
• Mood and alertness
• Cell growth and repair
• Memory and learning

Even the critical daily purging of toxins from our bodies is switched on and off by our master clock.

When our sleep cycle is disrupted, so are all the cues that keep the various systems running in good order. "Given that most people lose an average of 25 minutes of daily sleep in the first few weeks after DST," says Johnson, "it stands to reason that our health suffers." But, as she notes, there are other consequences to the time change.

The sleep-safety connection

Another result forcing our bodies out of alignment with their natural rhythms is the increase in accidents and injuries.

Johnson says, "Morning light is very important to mood and safety. The later sunrises and sunsets of DST can deprive us of this important effect causing our body rhythms to become misaligned with our social schedules affecting sleep and alertness. When we're forced to navigate life with too little sleep in the dark, bad things happen. In fact, one community in Florida lost eight kids to accidents at school bus stops in just one month in the morning hours when permanent DST occurred in the winter of 1974 and sunrises didn't occur until around 9 AM."

She adds that the number of workplace injuries, car accidents, and even sports injuries go up whenever a time shift occurs.

Preparing for the shift to Daylight Saving Time

While the merit of DST is being hotly debated across the country, for now, it's a part of our collective reality. But that doesn't mean you have to just suffer through it.

Johnson encourages people to use the weeks leading up to the time change to begin resetting their master clocks.

"You want to get your body ready for sleep either earlier or later, depending upon the time of year." She advises, "You can gradually change your sleep schedule by going to bed either 15 minutes earlier or later each night." Dr. Johnson provides additional tips on coping with the time change of Daylight Saving Time, or other sleep disruptions.

Johnson also recommends practicing good sleep hygiene. "A regular bedtime routine sends a signal to your brain that now is the time for sleep and can help you fall asleep faster and stay asleep. But, "she notes, "If the switch to DST causes sleep disruptions lasting longer than a few weeks, consider seeing your doctor who may recommend seeing a sleep specialist."

If you suspect that you may have a sleep disorder, speak to your physician and ask for a referral to the Baystate Regional Sleep Program. For more information, call 413-794-5600.