Woman Waking Up to Alarm Clock

Daylight Savings Time starts in the spring and ends in the fall for many people across the world and all across the United States.  Daylight Savings Time, or DST, began in the U.S. in 1918, two years after much of the world had already adopted it in 1916 after Germany and Austria started the trend.  The idea behind DST was to conserve energy consumption by providing as many hours of daylight in each time zone.  Unfortunately, while DST does help with energy conservation, it can wreak havoc on the body.

Disrupting the Circadian Rhythm

DST causes disruptions in each person’s Circadian rhythm.  Circadian rhythm is the proper name for the body’s internal clock.  It is a 24-hour cycle that the body uses to determine when to eat, when to sleep, when to get up, and to regulate other internal functions like digestion, repair and more.  In the spring, DST starts, and we put our clocks ahead one hour in most places across North America.  Other countries have different schedules for when DST begins and ends.

When the clock goes ahead one hour, it is said that we "lose an hour."  When the clock goes back by an hour in the fall, it is said that we "gain an hour."  However, even though timepieces say that is the case, the body really feels it.  The internal clock is a precision instrument, and like many other precision instruments, the most minute of changes can cause it to malfunction.

Many studies have been done since DST went into widespread when the U.S. Congress passed the Uniform Time Act in 1966, and nearly all of them report some sort of devastating effect on the body’s internal clock.  DST can cause major sleeping problems, sleep quality issues, and it can alter eating patterns in unfavorable ways.

DST Effects in Detail

It takes most people about a week to adjust to a DST change.  In the fall, when DST ends for the winter, people often find it easier to adjust their sleeping pattern, because it is easier to gain an hour.  If a person usually gets up at 6:00 a.m., the body decides it is time to wake up when the clock says it is only 5:00 a.m.  Unfortunately, most people tend to take the opportunity to stay up an hour later the night of the change, which causes a disruption, even if minor, in the body’s internal clock.  That causes tiredness to set in.

When people are tired, they tend to overeat and choose foods that provide short-term energy and fewer quality calories.  Furthermore, people who are predisposed to being "morning" people have a harder time adjusting to the fall time change than those who identify as being "evening" people.  One study also found that those with Seasonal Affective Disorder (SAD) or those who have a high global seasonality score, which is one of the determining factors in diagnosing SAD, have even more trouble adjusting to the time change.  DST changes also contribute to an increase in traffic accidents, especially in the fall.  While it is not yet known what the exact reason is, these accidents look like they are a result of a systematic loss of at least one hour of sleep for many people.

Compensating for the Loss

If at all possible, try going to bed 5 - 10 minutes later each night for the week leading up to the change.  These gradual increments may result a little less sleep each night when waking up at the regular time.  However, it is easier to change the internal clock gradually than it is to put it into overload and deal with the aftermath all at once.  Be prepared with healthy snacks that provide energy with fewer calories.  That way, you compensate for any overeating that may happen.

Alternatively, rather than forcing your internal clock to adjust, simply go to bed at the usual time and get up an hour earlier in the morning.  You will then have more time to relax in the morning or incorporate a more healthy breakfast before heading to work or school without causing your body to get out of sync with itself!

Last Updated: Wednesday, October 31, 2012