"It’s not one hour twice a year. It’s a misalignment of our biologic clocks for eight months of the year. When we talk about DST and the relationship to light we are talking about profound impacts on the biological clock, which is a structure rooted in the brain. It impacts brain functions such as sleep-wake patterns and daytime alertness,”- Beth Ann Malow, MD, Burry Chair in Cognitive Childhood Development, and professor of Neurology and Pediatrics in the Sleep Disorders Division at Vanderbilt Univ. Medical Center
It is now two days and counting before we once again change the clocks - this time from Daylight Saving Time (DST) back to standard time. Why must we put up with this inane nonsense each year? We know the clock changes are bad for the health of millions, but still we do it. This is also in the news now because 19 states have evidently made legislative moves to have DST all year round. Six of them have already enacted legislation to that effect. But they'd do well to hit the pause button.
For my money we just need to stick with standard time, no more changing clocks back to DST in March. There are also good, sound scientific reasons for this. First and foremost our biological clocks - based on circadian rhythms - are attuned to standard time, which is also Sun time (following apparent solar time). This apparent solar time can easily be assessed using a simple shadow stick apparatus, i.e.
Thus, one hour of apparent solar time passes for every 15 degrees of longitude the Earth rotates on its axis. The length of the shadow cast by the vertical stick enables differences, e.g. hours, to be estimated. Thus, a unit of apparent solar time can be estimated by taking the angle between two equal shadow stick positions on either side of high noon (null or minimal shadow length) and divided by 2. (The sketch shows a setup for Barbados.)
One standard time zone is generated via (360 deg/ 24 hr) = 15 deg/h or 15 degrees of longitude per hour - so be 15 degrees of longitude in expanse. To be sure, the Sun's "natural time" (apparent solar) is slightly erratic (by minutes, not hours) because it’s based literally on sundial time, and what’s called the equation of time. E.g.
"Most of our physiology is governed by a circadian clock. This body clock synchronizes to sun time."
But what if DST is thrown into the mix? Well, in DST the dark-light cycle doesn't change but the time does. That's the core problem because it means the body clock of circadian rhythms is thrown off. So there is a discrepancy between your biological clock and social clock (which governs time to get up for work, eat, sleep etc.) This then creates what those like Prof. Roennenberg call a "social jet lag". (WSJ, 'Why Daylight Saving Times Is Bad For You', March 5, 2020, p. A12):
"Daylight Saving Time means that we virtually live in another time zone without changing the day-light cycle. The problem is the misalignment. The circadian clock is trying to optimize our physiology . Now suddenly we have to do things which are not at the biologically appropriate time. It's a general stress of the physiology."
"The acute effect of daylight saving time in the days after the change are an increased risk of heart attack and stroke, studies show. The risk is usually in the days following the switch, and not long term, raising questions about whether the time change is triggering heart attacks that would happen anyway."
Prof. Beth Ann Malow of Vanderbilt offers her own thesis that the year in and year out switching times is bad for the brain, e.g.
She may have a point. There is also good evidence it significantly lowers productivity which the economists are always fretting over. Thus, a survey conducted by the American Association of Sleep Medicine showed that 55 % of Americans reported feeling tired after the transition to DST. Further, "the group's health advisory says moving into and out of DST can adversely affect sleeping and waking patterns for 5- 7 days."
Well, think about it. Whereas before the DST switch you awakened at 7:15 a.m. to arrive at work by 8:00 a.m. that now becomes effectively a wake up time of 6:15 a.m. because the clock time is moved one hour ahead. Everything is shifted and you're trying to catch up to the change because of it, as well as having lost an hour of sleep - and also on successive days.
The usual response to that is: "Well go to bed an hour earlier!" But it's not so simple because you're body clock has already been set to a certain sleep time and wake up time. All going to bed an hour earlier will mean is lying awake for an hour and tossing unless you take an Ambien - which has its own effects .