Fall Back to Standard Time: There Are Positive Implications for Health

By Dr. Coleen Andruss, Healthy Lifestyles

It’s that time of year when once again we go back to standard time. Which time of year do you like better? Most people would like to eliminate the time change altogether due to inconvenience. However, there are other implications that should be considered.

An hour may not seem like a big deal, but studies show that messing with the body’s internal clock twice a year does affect health. Fortunately, “falling back” to standard time is relatively benign. And while the negative effects are few, the positive effects are worth a close look. Consider the following studies:

• A study done at the University of Colorado demonstrated that during standard time in the fall, when we move the clocks back to gain an hour of sleep, the number of car accidents decreased by approximately 6 percent due to improvements in cognitive ability, alertness, and reaction time.

• Statistics published in the Journal of Clinical Medicine concluded that the extra hour of sleep gained at the onset of standard time caused a decrease in stress hormones. Even more important was the finding that the number of heart attacks decreased in the fall and winter when compared to the number of heart attacks in the spring and summer.

• A study by the American Heart Association showed that the Tuesday following the change to standard time in the fall, there was a 21 percent reduction in the number of heart attacks, and the Monday following the change to daylight saving time in the spring, there was a 24 percent increase in daily heart attack counts.

• The American Academy of Neurology demonstrated that there was an 8 percent overall decrease in ischemic strokes during standard time.

Interestingly, there are fewer human errors when we get more sleep. Studies show the risk of adverse medical events related to human error is 18 percent less in the fall. Productivity is higher after that extra hour of sleep as demonstrated by studies that indicate a decrease in non-work web browsing during standard time versus daylight saving time. When it comes to the effects that the time changes have on obesity and metabolic syndrome, the studies are a mixed bag. In the fall, diminished sun exposure causes serotonin levels to drop. Thus, mood can change, and the incidences of depression rise. Additionally, activity levels typically decrease during the fall and winter, and this can lead to weight gain.

On the flip side, moving that time clock and gaining an extra hour of daylight in the spring can cause difficulties with eating habits: you may get hungrier and become more irritable an hour earlier, and eating later than you are used to can result in overeating since hunger is driven by hormones. Therefore, the risk of weight gain leading to obesity and metabolic syndrome is higher in the spring and less likely during standard time.

Sunlight is critical for circadian rhythm, which is set by the timing and amount of bright light exposure a person gets during the day. During daylight saving time, your body is exposed to less morning light and more evening light. Morning light wakes us up and improves alertness; it is necessary to set our natural rhythms. When your internal clock is out of sync with the sun’s clock, you may feel tired in the morning and awake in the evening.

Sleep homeostasis is thrown off with this disruption of the circadian rhythm. This hormonal imbalance can lead to insomnia when the prolonged sunlight delays the production and release of melatonin. Melatonin promotes drowsiness, and because there is less exposure to sunlight in the evening with standard time, there is more melatonin and better sleep.

Germany was the first nation to fully adopt daylight saving time as an energy saving measure during World Wars I and II and during the energy crisis of the ‘70s. Currently, we have only four months of standard time, but we have eight months of daylight saving time. Legislators are looking at a permanent time change. Unfortunately, it leans in favor of daylight saving time instead of standard time. From a health standpoint, this is not in our favor. Standard time most closely approximates natural light with the sun directly overhead at noon.

The American Academy of Sleep Medicine has called for an end to daylight saving time because of its negative impact on health. Physicians have even testified at congressional hearings about the need to stay with standard time, citing the research that demonstrates its many benefits. So gear up to go back to standard time. Sweet dreams!

About the Author

Dr. Coleen Andruss practiced as an internist for ten years and has specialized in weight management for twenty-six years. She and her staff have personally experienced weight management issues and have a compassionate understanding of patients in the Healthy Lifestyles program. Dr. Andruss’s internal medicine background helps her to see underlying medical problems when formulating individual plans that work.