The chronic effects of DST have not been studied directly, but we know that DST increases the time difference between the social clock and the body clock (
Borisenkov et al., 2017). More and more studies show that time differences between the social clock and the body clock challenge our health (
Koopman et al., 2017;
Mota et al., 2017;
Parsons et al., 2015;
Roenneberg et al., 2012;
Rutters et al., 2014;
Wong et al., 2015), are associated with decreased life expectancy (
Borisenkov, 2011), shorten sleep (
Borisenkov et al., 2017;
Wittmann et al., 2006), cause mental (
Foster et al., 2013;
Levandovski et al., 2011) and cognitive problems (
Díaz-Morales and Escribano, 2015;
Haraszti et al., 2014), and contribute to the many sleep disturbances in our societies that are estimated to cost approximately 2% of the gross domestic product (
Hafner et al., 2017). If we established DST throughout the year, the chronic effects would become more severe not only because we have to go to work an hour earlier for an additional 5 months every year but also because body clocks are usually later in winter than in summer with reference to the sun clock (
Kantermann et al., 2007). The combination of DST and winter would therefore make the differences between body clocks and the social clock even worse and would negatively affect our health even more.