Time Change Could Prove Hazardous to Your Health

by William F. Shugart II

Although daylight-saving time was sold politically as an energy-conservation measure, it does no such thing. Studies conducted in Indiana prior to 2006, when that state operated under three different time regimes, show either no difference in energy consumption or a small increase in power usage during the months after clocks were moved one hour ahead.

The annual ritual of springing forward and falling back thus possibly produces no energy savings and may be counterproductive. It also requires those who live in places where daylight-saving time is observed to waste time twice a year adjusting their clocks and watches.

Yet the costs of switching between daylight-saving and standard time go far beyond the hassles of “losing” an hour in the springtime and “gaining” it back in the fall.

I am not a doctor and I do not play one on TV, but the medical profession – as Dr. Osvaldo Bustos of George Washington University's School of Medicine pointed out to me recently – has known for years that shifting time forward or backward has negative, and possibly deadly, health consequences.

A Swedish study published in The New England Journal of Medicine on Oct. 30, 2008, reports increases in the incidence of myocardial infarction (heart attack) after the beginning of daylight-saving time and the subsequent return to standard time. Depending on whether the shift occurred in the fall or spring, men and women were found to vary in the extent to which their heart attack risks were increased, but the study's authors concluded from the clinical evidence that time change triggered more myocardial infarctions in the two groups overall than they would have suffered otherwise.

The underlying causal mechanism has to do with how the hypothalamus regulates humankind's circadian rhythms. When the “clock” that governs those rhythms is abruptly shifted one hour forward or backward, it struggles to adjust the body's internal physical, chemical, electrical, hormonal and immunological environment to the new conditions.

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November 4, 2009

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