The Role of Timing of Dim Artificial Light at Night (dALAN) on the Weight of Mus musculus

Light pollution at night is a growing issue in many suburban and urban settings, commonly referred to as artificial light at night (ALAN). Many studies have been conducted as to how the intensity or wavelength of this lighting can disrupt the circadian rhythm but none have evaluated how the timing of this light could affect it. It is hypothesized that those that chronically experience dim artificial light at night (dALAN) after biological day will lead to a more pronounced disruption in the metabolic system and therefore will cause an increased level of weight gain. Mice were used as test subjects and were split into four groups: 1) 12 light, 12 dark (L:N); 2) 12 light, 4 dim, 8 off (L:D:N); 3) 12 light, 4 off, 4 dim, 4 off (L:N:D:N); and 4) 12 light, 8 off, 4 dim (L:N:D). The weight of these mice was tracked weekly to obtain the necessary data. These data were then analyzed for percent body weight increase and an ANOVA was run, obtaining a p-value of 0.000053. A Scheffe test was then run, finding a significant difference between L:N and L:D:N, L:N and L:N:D, and L:D:N and L:N:D:N. These results support that chronic dALAN exposure can lead to increased percent body weight changes. Future studies can further examine the possibilities as to why this is