Daylight saving time is a solution for which many forgot the problems

Tradition is a set of solutions for which we have forgotten the problems. Throw away the solution and you get the problem back. Sometimes the problem has mutated or disappeared. Often it is still there as strong as it ever was.

—Donald Kingsbury, Courtship Rite, 1982

In “Permanent standard time is the optimal choice for health and safety: an American Academy of Sleep Medicine position statement” Rishi et al¹ yell at daylight saving time (DST, a tradition that has lasted for 100 years) and ignore the problem it helped to solve.

In the introduction, the authors state that

human activities are affected by three clocks: the internal biological rhythm, also known as the circadian clock; the solar clock; and the social clock.… Under ideal conditions, all three clocks would be aligned to allow for optimal health and performance. The human biological clock is regulated by the timing of light and darkness, which then dictates sleep and wake rhythms. In daily life, the timing of exposure to light is generally linked to the social clock.

Surprisingly, the position statement does not ponder the fact that sunrise times, sunset times, photoperiod, and scotoperiod seasonally change at the latitude of the contiguous United States. In other words, the 3 clocks are misaligned by nature at 40° latitude. How can activities such as school and work begin aligned with the sunrise if this stimulus changes by 3 hours in 6 months at this latitude? They cannot—unless we introduce seasonal variability in social time. DST addressed (and helped to solve) this social and circadian problem.²

Unaware of this, many medical associations and societies have long pushed for canceling DST. But now, they look surprised in seeing that many would rather choose permanent DST over permanent standard time. The authors include that the attempt to introduce permanent DST in the United States in 1973 was “short-lived due to overwhelming unpopularity.” We certainly endorse this point of view. Short-lived attempts at permanent DST were also observed in the United Kingdom, Portugal, and Ireland (1970s); in Russia (2010s); and in Chile (2015). In view of that, how should we assess the known evidence that the biannual changing of the clocks is extremely long-lived in comparison: 100 years in the United Kingdom, Ireland, Portugal and in the major cities of the United States? Is that not also evidence of the extreme unpopularity of permanent standard time?

A bold conclusion, like “permanent standard time is the optimal choice for health and safety,” requires a fair balance of the cons and pros of the practice. Rishi et al¹ thoroughly addressed the cons and opted to ignore the health and safety pros that the practice has brought in terms of the alignment of the 3 clocks.

DISCLOSURE STATEMENT

All authors have seen and approved the manuscript. The authors report no conflicts of interest.