Linda Longo, at US Lighting Trends, summarized the issues involved in proposed legislation to make Daylight Savings Time permanent and year-round, in the US. As of today’s date, the Senate passed its version of the bill in March, while the House of Representatives has introduced its bill, but not acted on it.

Making Daylight Savings Time permanent has significant light and health consequences, as resetting clocks significantly impacts circadian rhythms and human health:

The American Academy of Sleep Medicine (AASM) – a professional society for the medical subspecialty of sleep medicine, which includes disorders of circadian rhythms – believes the U.S. should eliminate seasonal time changes in favor of a national, fixed, year-round time. According to the AASM, “current evidence best supports the adoption of year-round Standard Time, which aligns best with human circadian biology and provides distinct benefits for public health and safety.” (Read AASM’s full statement on the topic here)

Those opposed to DST are concerned by evidence that the body clock does not adjust easily to the seasonal time change even after several months. According to AASM, the worry is that “permanent DST could result in permanent phase delay, a condition that can also lead to a perpetual discrepancy between the innate biological clock and the extrinsic environmental clock, as well as chronic sleep loss due to early morning social demands that truncate the opportunity to sleep.”

There is concern that acute transition from standard time to DST could create public health and safety risks, including increased risk of adverse cardiovascular events, mood disorders, and motor vehicle crashes. The group added, “Although chronic effects of remaining in Daylight Saving Time year-round have not been well-studied, Daylight Saving Time is less aligned with human circadian biology — which, due to the impacts of the delayed natural light/dark cycle on human activity, could result in circadian misalignment, which has been associated in some studies with increased cardiovascular disease risk, metabolic syndrome, and other health risks. It is, therefore, the position of the American Academy of Sleep Medicine that these seasonal time changes should be abolished in favor of a fixed, national, year-round standard time.”

The full article is available here.