Response to “Saving Daylight Savings Time”

My old friend Gary Gaddis makes some fair points on Daylight Savings Time. DST may indeed give people another hour of daylight in the evening, during which they may be able to do more exercise. Personally, I do my exercise regimen in the morning. We can certainly acknowledge that dedicated bicyclists are a group which may benefit from DST. However, as I noted, there is a body of evidence in the literature that DST is generally harmful, or at best not beneficial. Most of it has to do with ill effects of the twice-a-year transitions. There may be offsetting benefit from increased exercise during the summer months, but it hasn’t been shown in the literature. Nor have there been studies on any correlation between Standard Time and increased obesity.

In the U.S., obesity rates have been rising since around 1960, and began accelerating around 1980, with further acceleration after 1995. Only in the last decade or so has the rate of obesity begun to level off, but at a high level.¹ As noted in my article, DST became universal in the U.S. in 1966, and after some fluctuation settled at seven months per year after 1986. Now, this positive correlation of DST with obesity certainly does not indicate causation. But it does make one think.