So the study of how light and biology interact is called chronobiology: * https://en.wikipedia.org/wiki/Chronobiology https://en.wikipedia.org/wiki/Chronobiolo

So the study of how light and biology interact is called chronobiology: * https://en.wikipedia.org/wiki/Chronobiology https://en.wikipedia.org/wiki/Chronobiology AFAICT, all national (US, CA) and international (EU) chronobiology societies, as well as many sleep researchers, state that from a health perspective, we should (a) get rid of the twice-yearly DST switching, and (b) stay on Standard ("winter") Time year-round. > As experts in biological clocks and sleep, we have been following the initiatives of the European Commission and California Proposition 7 to abandon the annual clock-time changes in spring and autumn. Although we recognize that there are advantages/disadvantages associated with any choice, we emphasize that the scientific evidence presently available indicates that installing perennial Standard Time (ST, or ‘wintertime’) is the best and safest option for public health. The negative effects of maintaining Daylight Saving Time (DST) will be higher. * https://srbr.org/wp-content/uploads/2018/10/SRBR-Statement-on-DST.pdf https://srbr.org/wp-content/uploads/2018/10/SRBR-Statement-o... > The Canadian Society for Chronobiology is advocating for the elimination of twice-yearly time changes. These changes, particularly in the spring, are not only inconvenient and socially disruptive, but also are responsible for short-term negative impacts such as increases in acute health events and accidents. In place of the time changes, we advocate for year-round Standard Time (ST, winter time) rather than Daylight Saving Time (DST, summer time). ST puts the social clock closer to our intrinsic body clock, our circadian rhythm, which is set by the dawn. DST moves dawn later, and creates social jet-lag due to the mismatch between our biological drive to wake up near dawn and the social demands for us to stay up later. Year-round DST is predicted to increase rates of chronic diseases, decrease economic performance, and increase inequities in society. Putative advantages of year-round DST, such as energy savings and benefits for farmers, are not supported by evidence. Previous experiments with year-round DST have proven to be unpopular. Therefore, year-round ST should be adopted as a public health measure. * http://www.chronobiocanada.com/official-statements http://www.chronobiocanada.com/official-statements > Daylight saving time (DST) refers to the practice of advancing clock time by 1 h each spring, with a return (setting back) to standard time (ST) each fall. Numerous sleep and circadian societies other than the Sleep Research Society have published statements in support of permanent ST, and permanent ST has also received support from multiple medical societies and organizations. This perspective dis- cusses the positive and negative health and economic consequences of permanent DST, permanent ST, and maintaining the status quo (DST for part of the year). After a thorough review of the existing literature, the SRS advocates the adoption of permanent ST. * https://sleepresearchsociety.org/wp-content/uploads/2022/11/zsac236.pdf https://sleepresearchsociety.org/wp-content/uploads/2022/11/... > […] 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. * https://jcsm.aasm.org/doi/10.5664/jcsm.8780 https://jcsm.aasm.org/doi/10.5664/jcsm.8780 And this does take into account different chronotypes (e.g., "night owls"): * https://www.frontiersin.org/articles/10.3389/fphys.2019.00944/full https://www.frontiersin.org/articles/10.3389/fphys.2019.0094... Of course a lot of the general public seems to lean towards year-round DST (e.g., "so I can do stuff after work"): > The chronobiology community advocates ending the biannual practice in many countries of adjusting their clocks to observe Daylight Saving Time (DST). Many governments are actively considering abandoning this practice. While sleep and circadian experts advocate the adoption of year-round standard time, most jurisdictions are instead considering permanent DST. In guiding advocacy, it is useful to understand the factors that lead governments and citizens to prefer the various options. […] * https://pubmed.ncbi.nlm.nih.gov/35382618/ https://pubmed.ncbi.nlm.nih.gov/35382618/